Beluga whale (Delphinapterus leucas), St. Lawrence Estuary population, recovery strategy: chapter 2
- 1.1 COSEWIC assessment summary
- 1.2 Species description
- 1.3 Populations and distribution
- 1.4 Needs of the St. Lawrence Estuary Beluga population
- 1.5 Threats
- 1.6 Actions already completed or underway
1.1 COSEWIC assessment summary
Committee on the Status of Endangered Wildlife in Canada (COSEWIC) Assessment Summary, as presented in the Assessment and Update Status Report (COSEWIC, 2004)Footnote 1:
Date of Assessment: May 2004
Common Name (population): Beluga (St. Lawrence Estuary population)
Scientific Name: Delphinapterus leucas
Reason for Designation: The population was severely reduced by hunting, which continued until 1979. High contaminant loads may have also contributed to the population decline. Aerial surveys since 1973 suggest that the decline has ceased, but do not provide clear evidence of a significant increase in numbers. Levels of many contaminants remain high in beluga tissues. The whales and their habitat are threatened by contaminants, vessel traffic, and industrialization of the St. Lawrence watershed.
Range in Canada: Quebec, Atlantic Ocean
Status History: Designated Endangered in April 1983 and in April 1997. Status re-examined and designated as ThreatenedFootnote 2 in May 2004. Last assessment based on an update status report.
1.2. Species description
The beluga is a small, toothed whale of the Monodontidae family, found in the northern hemisphere and adapted to Arctic and subarctic conditions. The species is characterized by the absence of a dorsal fin, a thick skin and tough dorsal ridge (used to break ice), and a rounded structure, called a melon, on the dorsal surface of the head, which is filled with lipids and facilitates echolocationFootnote 3. Adults are distinguished by their white skin. An adult beluga can weigh up to 1900 kg and grow to between 2.6 and 4.5 m in length, the female adult attaining only 80% of the male's length, or up to 3.5 m (Vladykov, 1944; Lesage and Kingsley, 1998; COSEWIC, 2004).
Calves are a greyish brown colour with occasional darker markings. Newborn calves measure 150 cm in length, nearly half the size of the mother, and weigh approximately 78 kg. At two years of age, they reach 60% to 65% of the mother's length (Brodie, 1971; Lesage and Kingsley, 1998). Older juveniles gradually become lighter coloured up to the age of sexual maturity, when they are completely white (Sergeant, 1973; Heide-Jørgensen and Teilmann, 1994; Lesage and Kingsley, 1998).
1.3. Populations and distribution
1.3.1 Global distribution and populations
The global beluga population can be grouped into 29 different populations spread throughout the circumpolar region between latitudes 47° N and 80° N (Martin and Reeves, 2000). Belugas are found in the waters of Alaska, Canada, Greenland, Norway, and Russia (Figure 1). These populations migrate between habitats, depending on the season and their biological requirements (for example, feeding, calving, or wintering). In summer, belugas show high site fidelity, gathering in specific estuaries and glacier fronts.
There is no reliable estimate of the total numbers of belugas globally. However, Martin and Reeves (2000) gave estimates of the 29 populations that have been identified, which could total between 98 000 and 120 000 individuals. In comparison, according to the COSEWIC status report (2004), beluga stocks in North America could total more than 100 000 individuals, of which 85 000 are in Canadian waters. Based on their summer distribution, belugas in Canadian territory have been grouped into seven populations, as illustrated in Figure 2 (COSEWIC, 2004; MPO, 2005b). COSEWIC assessed all the Canadian populations and designated their status (endangered, threatened, special concern, not at risk). Currently, only the St. Lawrence Estuary population is listed in Appendix 1: List of Wildlife Species at Risk.
Figure 1. Global distribution of belugas
Description of Figure 1
Global distribution of belugas (adapted from Reeves, 1990). The map represents the Arctic ocean surrounded by Russia, Scandinavia, Canada, and Alaska; the beluga is found off the coasts. Belugas are found in the waters of Alaska, Arctic Canada, Western Greenland, Northern Norway, and Northern and Western Russia.
This distribution of the North American beluga population may change as further genetic information becomes available. Nuclear and mitochondrial DNA studies have shown that the North American beluga population is not homogeneous (Brown Gladden et al., 1997; Brown Gladden et al., 1999b; de March et al., 2002; de March and Postma, 2003). In fact, it is divided into two different evolutionary units (east and west) and sub-divided into eight management areas according to their summer distribution.
Figure 2. Location of the seven Canadian beluga populations
In grey is the distribution area and in black are the main summering areas.
Description of Figure 2
Location of the seven Canadian beluga populations. The map represents the distribution of the seven beluga population found in the waters of Greenland, Canada and Alaska. 1) St. Lawrence Estuary population: summering area: St. Lawrence Estuary, distribution area: St. Lawrence Estuary and Gulf; 2) Ungava Bay population: summering area: southwest Ungava Bay, distribution area: Ungava Bay and Hudson Straight; 3) Eastern Hudson Bay population: summering area: central Eastern Hudson Bay, distribution area: Eastern Hudson Bay; 4) Western Hudson Bay population: summering area: Eastern Manitoba and Northern Ontario, distribution area: Western Hudson Bay; 5) Eastern High Arctic and Baffin Bay population: summering area: around Sommerset Island, distribution area: from Western Baffin Island to Western Greenland; 6) Cumberland Sound population: summering area: Cumberland Sound, distribution area: Eastern Baffin Island; 7) Eastern Beaufort Sea population: summering area: Beaufort Sea, distribution area: Northern Canada and Northern and Western Alaska. Adapted from COSEWIC, 2004.
1.3.2 Distribution of the St. Lawrence population
The St. Lawrence Estuary belugas live downstream of the densely populated, highly industrialized Great Lakes Region, along a major marine navigation corridor containing a wide range of pollutants. Mitochondrial and nuclear DNA analyses and functional genomic studies reveal that the St. Lawrence belugas are genetically isolated from other populations (Brennin et al., 1997; Brown Gladden et al., 1997; Brown Gladden et al., 1999a; Murray et al., 1999; de March and Postma, 2003). They constitute a lineage whose closest relatives are the belugas of the east coast of Hudson Bay (Brown Gladden and Clayton, 1993; Brown Gladden et al., 1997; Brown Gladden et al., 1999a; COSEWIC, 2004). However, genetic analyses suggest that these two groups have been separate for approximately 8000 years (de March et al., 2002).
The St. Lawrence belugas are also geographically isolated from other populations in the eastern Arctic, even though the distance that separates them is theoretically not insurmountable. Belugas are occasionally sighted in the northeast and south of the Gulf of St. Lawrence, along the Labrador coast, and close to Newfoundland, Nova Scotia, and the eastern coast of the United States (Reeves and Katona, 1980; Michaud et al., 1990; Curren and Lien, 1998). Vladykov (1944) suggested that the St. Lawrence population was not completely isolated from the more northern populations, and that northern belugas might have immigrated to the St. Lawrence. Nevertheless, it is impossible to accurately evaluate the magnitude of these migrations or to ascertain whether Arctic belugas have penetrated the St. Lawrence Estuary in recent history.
The distribution of the St. Lawrence belugas was first reported by Vladykov (1944). The area covered in summer extended east along the North Shore to Natashquan and along the south shore to Grande-Vallée (Figure 3). Spring distribution extended further west, around l'Île aux Coudres and further east and south to the coastal waters of the Gaspé Peninsula and the north shore of the Bay des Chaleurs. Autumn distribution included the Saguenay Fjord and extended west past Quebec City.
Figure 3. Historic distribution area of the St. Lawrence beluga
Description of Figure 3
Historic distribution area of the St. Lawrence beluga, adapted from Vladykov, 1944. The map represents the historic distribution area of the beluga in the St. Lawrence Gulf and Estuary, including the Saguenay River. The area covered in summer extended east along the North Shore to Natashquan and along the south shore to Grande-Vallée. The total distribution area extended to Québec and south of the Gaspé Peninsula.
Although the total distribution area is smaller than it used to be, the St. Lawrence beluga still covers a territory of over 8000 km2 in the St. Lawrence Estuary, the Gulf of St. Lawrence, and the Saguenay River (Michaud, 1993a; Fisheries and Oceans Canada (DFO) and World Wildlife Fund (WWF), 1995). The current summer distribution zone, which has changed very little in the last 20 years, is only a portion of what it was historically (Michaud et al., 1990; Lesage and Kingsley, 1998; Gosselin et al., 2007). The population is concentrated at the mouth of the Saguenay River, where it occupies an area of 2000 km2 extending from the Battures aux Loups Marins across from Saint-Jean-Port-Joli to Rimouski on the south shore of the St. Lawrence River and Forestville on the North Shore (Figure 4). In the last few years, almost thirty belugas have been sighted in the Estuary east of Rimouski and Forestville and in the area of Sept-Îles, suggesting a wider distribution than was previously thought (Kingsley and Reeves, 1998; Gosselin et al., 2007). The summer distribution also extends into the Saguenay River, from the mouth of the river to Saint-Fulgence.
Figure 4. Present distribution area of the St. Lawrence beluga
Description of Figure 4
Present distribution area of the St. Lawrence beluga, adapted from Michaud, 1993a. The map represents the present distribution area of the beluga in the St. Lawrence Gulf and Estuary, including the Saguenay River. The summer distribution area extends from Saint-Jean-Port-Joli to Forestville, including the Saguenay River up to Saint-Fulgence, and the total distribution area extends to Sept-Îles.
The beluga distribution outside of summer is not well known. Sightings are rare in spring and fall, and the distribution in these seasons is thought to be similar to that for summer (Boivin and Michaud, 1990; Michaud and Chadenet, 1990; Michaud et al., 1990). This population is partially migratory, moving to the northwest sector of the Gulf of St. Lawrence in the winter (Michaud et al., 1990; Lesage and Kingsley, 1998; Kingsley, 1999). Occasional sightings, along with aerial surveys conducted in 1989 and 1990, suggest that the winter distribution area extends downstream into the Gulf, all the way to Sept-Îles on the North Shore (Sears and Williamson, 1982; Boivin and Michaud, 1990). Small groups have also been sighted in the Estuary up to Rivière-du-Loup. It is likely that the winter distribution varies from year to year, depending on ice conditions (Vladykov, 1944; Boivin and Michaud, 1990). In early spring, belugas can be found off the Gaspé Peninsula, all the way upstream to the Battures aux Loups Marins (Michaud and Chadenet, 1990).
1.3.3 Abundance and trends of the St. Lawrence population
From an estimated historical population of between 7 800 and 10 100 whales (DFO, 2005b; Hammill et al., 2007), the St. Lawrence belugas dropped to a low of approximately 1 000 whales in the years following the ban on hunting in 1979 (Hammill et al., 2007). It is difficult to compare pre-1998 population estimates with later estimates because early aerial counts did not factor in submerged, non-visible animals. A correction factor of 209% must therefore be used to account for submerged whales (Kingsley and Gauthier, 2002). This correction factor is similar to those obtained in telemetry surveys of Arctic belugas, from 180 to 290% (Kingsley and Gauthier, 2002).
Since 1988, abundance surveys based on aerial photographs have been standardized to allow both accurate comparison of population estimates and the monitoring of trends. However, the reduced number of belugas, their gregariousness, their uneven spatial distribution, and the time they spend submerged can account for some of the variability in population estimates across surveys (Gosselin et al., 2007). Aerial survey data between 1988 and 2005 indicate that the population increased slightly, but not statistically significantly, from 900 whales in 1988 to just over 1200 in 2005, or approximately 12% of historical levels (Hammill et al., 2007) (Figure 5). The population growth rate has been estimated, with a great deal of uncertainty, at 1%. This is very slow for a population that is no longer being harvested (DFO, 2005b). Normally, an unexploited population of belugas whose numbers do not exceed the environmental carrying capacity should grow at an annual rate of 2.5% to 3.5% (COSEWIC, 2004) and up to a maximum of 4% (DFO, 2005a). Note that, given the uncertain estimates of the current beluga population, it should take several years of monitoring to detect any change in size. Michaud and Béland (2001) estimate that with a steady 3% annual growth rate, it will take 20 years to detect a trend using aerial surveys every 2 to 3 years, and at only 1%, this should take 40 years, not 24 years, as suggested by the St. Lawrence Beluga Recovery Team (DFO and WWF, 1995).
Figure 5. Population estimates for the St. Lawrence beluga from 1988 to 2005, corrected index and standard error
Description of Figure 5
Population estimates for the St. Lawrence beluga from 1988 to 2005, corrected index and standard error (adapted from Gosselin et al., 2007). The figure is a line graph showing population estimates and their standard errors. The population increased slightly, but not statistically significantly, from 900 whales in 1988 to just over 1200 in 2005.
Since 1982, the causes of beluga deaths have been monitored under the carcass monitoring program carried out by DFO, Parks Canada, the St. Lawrence National Institute of Ecotoxicology (SLNIE), the Faculty of Veterinary Medicine of the University of Montreal, and several other partners (for a review of publications, see Measures, 2007a). The program provides for the transportation of carcasses for post-mortem examination, when possible, or for sampling individual data and tissues.
Between 1983 and 2008, according to the database of the Canadian Cooperative Wildlife Health Centre, 389 beluga carcasses were found along the St. Lawrence, ranging from 9 to 24 each year, for an average of 15 per year. Beluga age was estimated in 296 carcasses: 9% were calves (less than one year), 12% were juveniles (from 1 year to sexual maturity, around 10 to 14 years), and 79% were adults (more than 10 to 14 years). Mean age of the stranded belugas was estimated at 34 years. Most dead individuals were between 41 and 50 years of age. One 80-year-old beluga carcass was found (Yves Morin, DFO, unpublished data). However, the early-age mortality is probably higher than the stranding data suggest, because carcasses of juveniles, which are greyish-brown in colour, are more difficult to spot on shore and less buoyant (Measures, 2007a). There has been no change in the age distribution of stranded whales over the years, and a high proportion are adults (Kingsley, 2002). Both the average age at death and the life expectancy once maturity is reached appear reasonably high, and there are no indications of mass mortality events or unusual mortality rates in belugas of reproductive age (Lesage and Kingsley, 1998; Kingsley, 1999).
Concerning calf production, Béland et al. (1988) calculated that immature animals (not counting yearlings) should account for 28% to 30% of the St. Lawrence belugas to enable the population increase required for recovery. Gray beluga counts based on aerial photographs and the proportion of juveniles observed during a ship survey indicate that juveniles make up approximately 30% of the population (Michaud, 1993b; Desrosiers, 1994; Kingsley, 1996, 2002), a high enough percentage to allow for recovery of the population. The calves counted in aerial surveys amounted to 8% of all the belugas counted, but this proportion varies considerably across surveys (from 2% to 16%). This may reflect a variability in calf production in St. Lawrence belugas, or it may simply be due to the difficulty in spotting calves at their mother's side from the air (Kingsley, 1993, 1996; Hammill et al., 2007). The carcass-based reproductive rate estimates are slightly below the expected rates for a species with a three-year reproductive cycle, but a sample bias could have caused underestimations (Béland et al., 1993).
Nothing in the overall findings suggests either a high mortality rate in adults or a significant deficit in the number of new calves (Lesage and Kingsley, 1998; Hammill et al., 2007). Hammill et al. (2007) hypothesized that the St. Lawrence beluga population has not recovered following the hunting ban because high juvenile mortality rates are preventing individuals of reproductive age from entering the population. Better estimates of reproductive and mortality rates will be needed to confirm this hypothesis.
1.4 Needs of the St. Lawrence estuary beluga population
1.4.1 Habitat and biological needs
Biology and reproduction
In the St. Lawrence Estuary, belugas appear to mate between April and June (Vladykov, 1944). After a gestation period of about 14.5 months, females give birth to a single calf sometime between June and August (Béland et al., 1990; Béland et al., 1992). The nursing period lasts an estimated 20 to 32 months (Brodie, 1971; Sergeant, 1973; Seaman and Burns, 1981). Females can therefore produce a young about every three years, during which gestation and lactation overlap for a variable period.
Beluga age is determined by counting the number of growth-layer groups in their teeth. Radiocarbon dating has recently demonstrated that growth-layer groups form only once a year in belugas and not twice a year as was previously believed (Stewart et al., 2006; Lockyer et al., 2007; Luque et al., 2007). Females are now believed to reach sexual maturity at between 8 and 14 years of age, and males slightly later, at between 12 and 14 years (Brodie, 1971; Sergeant, 1973; Heide-Jørgensen and Teilmann, 1994). The longevity of the beluga is estimated at between 30 and 60 years, and possibly more than 80 years, but because their teeth wear down, stop growing, and fall out, it is difficult if not impossible to determine the maximum lifespan (Lesage and Kingsley, 1995; DFO, 2005b). Females can probably continue to reproduce throughout their entire life, although the gestation rate in older females appears to diminish (Burns and Seaman, 1985). McAlpine et al. (1999) discovered the carcass of a 68-year-old female beluga from the St. Lawrence Estuary population that showed signs of recent reproductive activity and was in the final stages of lactation.
The beluga is a typical cold-water marine mammal. In winter its distribution is associated with areas of fast ice where open water provides air access (Barber et al., 2001). In the summer, beluga whales concentrate in specific estuaries, with high site fidelity (Fraker et al., 1979; Finley, 1982). In the St. Lawrence Estuary, belugas gather in certain areas more regularly (Pippard and Malcolm, 1978; Michaud, 1993a; Lemieux Lefebvre, 2009).
In summer, the St. Lawrence Estuary belugas break up into herds that are distinguished by age and sex (Sergeant, 1986; Michaud, 1993a, 1996). Groups of adults accompanied by juveniles inhabit mainly the upstream portion of the summer habitat, in the brackish, relatively warm waters of the Middle Estuary and the Saguenay Fjord (Michaud, 1993a). Along with the variability in salinity and temperature that characterizes these two parts of the Estuary, there are substantial differences in structural parameters such as total breadth, the presence of numerous islands, bathymetric configurations, and complex current flow patterns, all of which combine to create a mosaic of highly varied habitats (Michaud, 1993a). Despite the low proportion (less than 5% on average) of belugas sighted in abundance surveys in the Saguenay River, the regular summer frequentation by these whales makes this area particularly important (Michaud, 1993a; Chadenet, 1997; Gosselin et al., 2007). Groups composed of adults only, on the other hand, prefer the central, downstream sectors of the summering area, in the colder, deeper, more saline waters of the Estuary (Michaud, 1993a). Michaud (1993a) provides a more precise description of the summer distribution of the different beluga herds, defined by the percentage of juveniles included (Figure 6).
Figure 6. Summer distribution of St. Lawrence belugas by herd composition
Description of Figure 6
Summer distribution of St. Lawrence belugas by herd composition, adapted from Michaud (1993a). The map shows the St. Lawrence Estuary where are located summering areas for the different types of herds of belugas. Herds of adults with young are found around Île aux Coudres, Îles de Kamouraska, Rivière-du-Loup, and Saint-Siméon. Herds of adults only are found in the Laurentian channel off Les Escoumins. Mixed herds (lone adults and young with adults) are found in the Saguenay River, the head of the Laurentian channel and southern portion of the estuary. Inset: the location of the sector in Quebec.
In terms of the food chain (trophic level) the beluga is a predator, similar to certain seals and sea birds, other cetaceans, and fishermen (Lesage et al., 2001). Its diet consists of approximately 50 different species of fish and invertebrates (Vladykov, 1946; Kleinenberg et al., 1964; COSEWIC, 2004). Vladykov (1946) was the first to document the beluga's diet by analyzing the stomach contents of 165 whales. He identified mainly the following species: capelin (Mallotus villosus), American sand lance (Ammodytes americanus), cod (Gadus morhua, G. ogac), polychaetes (Nereis sp.), and cephalopods, including squid (Illex illecebrosus). The author found no trace of American eel (Anguilla rostrata) or rainbow smelt (Osmerus mordax) in his samples, but he did document reports that these two species had served as beluga prey. More recently, observations of belugas feeding and analyses of stomach contents have shown that belugas also prey on eels, herring (Clupea harengus), tomcod (Microgadus tomcod), and smelt (Bédard and Michaud, 1995; Bédard et al., 1997).
Two recent methods use biological markers such as stable isotopes in muscle tissue and fatty acids in the subcutaneous layer of fat to more accurately describe the beluga's place in the food chain with respect to its competitors (Lesage et al., 2001; Nozères, 2006). Researchers have found that belugas are generally at an intermediate trophic level, but that male and female belugas do not share exactly the same trophic level, females being at a lower level. This difference may be explained by differences in their consumption of benthic organisms (a lower trophic level) and by segregation of the sexes in different habitats, as females feed in less saline, more estuarine waters than males do.
Kastelein et al. (1994) studied the feeding habits of belugas in captivity. They concluded that, at temperatures ranging between 10 and 12 degrees Celsius, a juvenile beluga weighing 200 kg consumes the equivalent of 4.5% of its body weight per day, whereas an adult beluga weighing 1400 kg consumes 1.2%. Thus, in the wild, an adult female weighing between 600 and 700 kg would consume approximately 4900 kg of fish per year. Kingsley (2002) estimated that if a beluga population of about 1240 whales consumed 2% of their combined body weight a year, the total would come to 4500 metric tons. It is currently impossible to determine the quantity of food available for belugas in the St. Lawrence Estuary due to insufficient information about their diet and the lack of reliable estimates of prey populations.
1.4.2 Ecological role and anthropogenic value
The St. Lawrence Estuary belugas are part of the estuarine food web. Although highly placed predators on the food chain, they are also potential prey for killer whales (Orcinus orca) and some shark species such as the Greenland shark. Given the population size changes since the 1930s, the ecological role of the beluga appears to have diminished over the years (DFO, 2005a; Lawson et al., 2006).
In the 1970s, the vulnerable status of the beluga helped raise awareness of the contamination of the St. Lawrence and Saguenay Rivers and the need to protect marine diversity (Ménard et al., 2007). The beluga has become a Canadian symbol of wildlife threatened by industrialization and the over-exploitation of natural resources. Because belugas inhabit a relatively southern region where they are easily accessible to whale watchers, ecologists, and research scientists, they have received considerable attention. Moreover, the high levels of contaminants found in belugas have highlighted the issue of toxic chemical bioaccumulation in the St. Lawrence River (DFO and WWF, 1995). Consequently, the beluga has become an indicator of environmental quality (including human health, Measures, 2007a), and has heightened awareness of the importance of restoring the St. Lawrence ecosystem (DFO and WWF, 1995; Ménard et al., 2007). A recent survey polled Canadians on the economic benefits of rehabilitating marine mammal populations in the St. Lawrence Estuary. The results showed that Canadian citizens were concerned about protecting marine mammals and that they wanted Canada to invest more in protecting the St. Lawrence belugas, for instance, by establishing the St. Lawrence Estuary Marine Protection Area (Olar et al., 2007).
1.4.3 Limiting factors
Belugas have a long life expectancy, delayed sexual maturity, and low reproductive rate. In the event of mass mortality, the St. Lawrence beluga population would take a long time to return to its current level, compared to species with a shorter generation time.
Beluga hunting drastically reduced the population to a genetic bottleneck (Reeves and Mitchell, 1984; Patenaude et al., 1994; Murray et al., 1999). The number of mature belugas has been estimated at 660, or 60% of the total estimated population of 1100 whales (DFO 2005a). This is less than the minimum of 1000 mature animals required to maintain genetic diversity, as determined by COSEWIC. Greatly reduced populations can lose their genetic diversity, either by random allelic loss, known as genetic drift, or by reproduction between related animals, known as inbreeding. The genetic diversity of the St. Lawrence belugas is low compared to other Canadian beluga populations, which suggests that either genetic drift, inbreeding, or both have influenced the genetic characteristics of this population (Patenaude et al., 1994; Mancuso, 1995; Murray et al., 1999; de March and Postma, 2003). In addition, because this population is isolated from other beluga populations, 'genetic rescue' from other populations is unlikely (Pippard, 1985b; Sergeant and Hoek, 1988; Lesage and Kingsley, 1998).
Low genetic diversity can hinder population recovery by decreasing reproductive rates, increasing mortality rates, or both. Reproductive rates may diminish when genetically similar individuals mate, resulting in greater risk for unsuccessful fertilization or foetal loss, and therefore overall lower reproductive performance (e.g. Knapp et al., 1996). Individuals with low genetic variability also have compromised immune systems, higher vulnerability to pathogens and chemical products, and therefore higher mortality rates as demonstrated in other species (e.g. Paterson et al., 1998; Siddle et al., 2007). The low genetic diversity of the St. Lawrence beluga population, when compared to Arctic populations, could be involved in the lack of recovery.
In 1995, when the first St. Lawrence beluga recovery plan was being drawn up, members of the Recovery Team considered the possibility of introducing Arctic belugas into the St. Lawrence Estuary to increase the population's genetic diversity. They concluded that the St. Lawrence belugas were threatened more by demographic and ecological than genetic factors. It was also believed that introducing Arctic belugas would involve substantial risks, such as introducing new diseases, thereby outweighing the benefits. The current Recovery Team concurs with these conclusions.
Natural factors can cause the loss of a few individuals, and thus contribute to limit the recovery of the beluga population. Killer whales are natural predators of the beluga (Heide-Jørgensen, 1988), but no cases have been reported in the St. Lawrence Estuary in the last few decades. Predation does not appear to be a significant limiting factor for the recovery of the St. Lawrence beluga. Belugas may become trapped by ice and unable to swim to open water. Although no cases have been reported in the St. Lawrence beluga population, entrapment causes the deaths of many whales in northern populations. Belugas can also become trapped in smaller rivers and narrow waterways, and be unable to make their way back to the sea. Each year, some belugas migrate outside their normal distribution area, and some make it all the way south to the New Jersey coast (Reeves and Katona, 1980; Michaud et al., 1990). Although only one to three individuals might emigrate to other regions per year, the long-term cumulative effect on the population is negative (Sergeant and Hoek, 1988; Hammill et al., 2007). It is not known whether these whales ever return to the St. Lawrence.
1.5.1 Causes of mortality in St. Lawrence belugas
A threat is a factor, natural or anthropogenic (man-made), that affects or could affect the recovery of the St. Lawrence belugas. Causes of mortality are studied to better understand the factors that threaten this population. According to data gathered under the beluga carcass monitoring program, infectious diseases caused by parasites (20.0%) or bacteria (17.7%) were the most frequent causes of death found in beluga necropsies (Table 1). Some of the diseases are discussed in detail in the section Epizootic disease.
|Cause of Mortality||Age Group||Total
|Bacterial Infection||2 (13%)||2 (9.5%)||27 (19.4%)||31 (17.7%)|
|Dystocia (difficult delivery)||10 (67%)||0 (0%)||4 (3%)||14 (8%)|
|Parasitic Infection||2 (13%)||14 (66.7%)||19 (13.6%)||35 (20%)|
|Trauma||0 (0%)||0 (0%)||10 (7%)||10 (5.7%)|
|Tumors||0 (0%)||0 (0%)||28 (20%)||28 (16%)|
|Unknown||0 (0%)||4 (19%)||42 (30%)||46 (26.3%)|
|Other||1 (7%)||1 (4.8%)||9 (7%)||11 (6.3%)|
|Total number of carcasses||15||21||139||175|
Necropsies also revealed the presence of one or several terminal malignant tumours (cancer) in 20% of the 139 adults examined between 1983 and 2006. Tumour formation would be attributable to exposure to one or more carcinogens, weakened resistance to tumour growth due to viral or bacterial infection, or genetic predisposition (De Guise, 1998; Martineau et al., 1999; Martineau et al., 2002a; Martineau et al., 2002c; Measures, 2007a). The section Contaminants and Appendix 2 describe the carcinogens in greater detail. Cancer is most often found in older animals (Martineau et al., 2002a; Lair, 2007; Measures, 2008).
Traumatic lesions (for example, vertebrae fractures, deep lacerations in the skin and lungs), possibly caused by ship strikes, were found in 5.7% of cases (Table 1). Details are provided in the section Ship Strikes.
1.5.2 Classification of threats
According to the latest COSEWIC status report (2004), the St. Lawrence Estuary beluga population was massively depleted by hunting, which was banned in 1979, and is now being threatened by
- Industrialization and pollution, which may be responsible for the high rates of chronic diseases such as cancer observed in stranded animals
- The small population size and low genetic diversity (consanguinity), which may affect the reproductive rate
- Habitat loss and disturbance, especially anthropogenic noise caused by marine navigation and whale watching activities
- Competition for food resources with commercial fishermen and increasing populations of certain marine mammals, including some seal species.
The St. Lawrence belugas live downstream of the Great Lakes and the St. Lawrence fluvial section, a densely populated, highly industrialized region of Canada and the United States. Although no single factor has been directly linked to the lack of recovery, this population inhabits a highly polluted ecosystem in the middle of a busy commercial shipping corridor. Belugas are consequently exposed to a number of human activities that may cause deaths directly, such as ship strikes and entanglement in fishing nets, or indirectly, such as contaminants, which may increase rates of chronic diseases such as cancer, disrupt immune system efficiency, and increase vulnerability to pathogens. The smaller population and its geographical isolation increase these risks for extinction.
Ten threats to population growth have been identified (Table 2), four of which affect the population as a whole. These are (1) contaminants, (2) anthropogenic disturbances, (3) reduced abundance, availability, and quality of prey, and (4) other degradation of habitat. Three threats can affect or cause the death of several individual animals yearly: ship strikes, entanglement in fishing gear, and scientific research. Three additional threats can limit the recovery of the St. Lawrence beluga population when they occur: toxic spills, harmful algal blooms, and epizootic (animal) diseases. To this list we may add an historical threat: hunting. This list is based on current information, which remains limited and is subject to change as data and the situation evolve.
Because of the reduced size of the population, even activities that affect only a few individual belugas can have serious repercussions on the entire population. It is also important to take into account the cumulative and synergistic effects of these threats on the St. Lawrence beluga population. Furthermore, climate change will most certainly weigh on the impacts of identified threats to the St. Lawrence beluga, and will alter its habitat. The beluga is essentially an Arctic species that is confined to a boreal environment. The semi-arctic conditions of the Estuary have maintained the population since its separation from the Arctic populations 8000 years ago.
Global warming, which is occurring at a faster rate than was initially forecast, should increase mean temperatures by 1.5° C to 5.5° C by 2050 in central and southern Quebec (Bourque and Simonet, 2008). Between 1960 and 2003, temperature increases of 0.4°C to 2.2°C were recorded in several regions of southern Quebec (Yagouti et al., 2006). Although temperature increases in eastern Quebec have been less than in western Quebec, the impact of this warming trend on the upstream section of the St. Lawrence River basin and in northern Quebec and the Arctic will be felt all the way into the Estuary and the Gulf of St. Lawrence.
Climate change is not considered a threat but rather a factor influencing the impact of other threats. Interaction between climate change and each threat will be discussed below, when applicable.
|Threat||Extent||Occurrence||Frequency||Causal certainty||Severity||Level of concern|
|Hunting and harassment||Widespread||Historical||Nil||High||High historically||Nil|
|Reduction in the abundance, quality, and availability of prey||Widespread||Imminent||Continuous||Low||Medium||High|
|Other habitat degradation||Localized||Current||Continuous||High||High||High|
|Entanglement in fishing gear||Localized||Current||Seasonal||Medium||Medium||Medium|
|Toxic spills||Widespread||Anticipated||Recurrent||Medium||Low to high||Medium|
|Harmful algal bloom||Localized||Anticipated||Recurrent||Medium||Medium to high||Medium|
|Epizootic diseases||Widespread||Anticipated||Recurrent||Medium||Low to high||Medium|
1.5.3 Description of threats
1) Hunting and harassment
Hunting is considered the main cause of the decline of the St. Lawrence beluga population, which was estimated at several thousand at the end of the 19th century (Vladykov, 1944; Reeves and Mitchell, 1984; Hammill et al., 2007). Commercial whaling began in the 1600s and continued almost uninterrupted until the 1950s. From 1880 to 1950, the period of the most intensive whaling, up to 15 000 belugas were killed (Reeves and Mitchell, 1984). In the 1920s, commercial fishermen considered the belugas competitors, so the government of Quebec offered a $15 bounty for each animal killed and subsidized the use of bombs to drive belugas out of fishing areas (Anon., 1928; Grenfell, 1934; Scharrer, 1983). Subsistence and sport hunting continued into the 1970s. Due to the dramatic decline in beluga stocks and a shrinking distribution area, hunting was officially banned in 1979 under the federal Fisheries Act. Some cases of poaching were reported after the ban on hunting came into force (N. Ménard, Parks Canada, pers. comm.). The hunting ban remains in effect today, and poaching is no longer considered a problem.
Current threats to the population
Contaminants, anthropogenic disturbances, reduction in the abundance, quality, and availability of prey, and other degradation of habitat are currently considered the most serious threats to the recovery of the St. Lawrence beluga. These threats affect the overall population, and their impacts may be difficult to detect.
Contamination of the aquatic environment has a number of different sources (for example, agricultural, industrial and municipal waste, maritime shipping, dredging operations, oil and gas development, aquaculture), and it can also affect marine mammals and their prey in many different ways (Colborn and Smolen, 1996; Aguilar et al., 2002). Water, sediments, and organisms in the St. Lawrence contain a wide variety of contaminants. Consequently, the resident beluga population has been exposed to numerous toxic chemicals for many years (a summary of the main types of contaminants is presented in Appendix 2). The various toxic chemicals that make their way into the St. Lawrence Estuary are present in the water column, and can accumulate in both living organisms and the sediment.
The beluga occupies a high position in the food chain, which means that certain contaminants in their diet can be concentrated within their bodies, a phenomenon known as biomagnification. Concentrations of persistent contaminants increase with increasing level of the food chain. The beluga's tissues therefore contain higher concentrations of contaminants than both its prey and the environment (DFO, 2002). The beluga's thick layer of subcutaneous fat stores persistent contaminants, and due to its longevity, the beluga can accumulate contaminants over a long period of time. Finally, historical data show that belugas feed in part on benthicFootnote 4 prey, which are more susceptible to contamination from pollutants that have accumulated in the sediment. Belugas are therefore particularly at risk for the effects of long-term contamination. Belugas are also exposed to contaminants that do not accumulate in tissues but could nevertheless impact their health.
Even after a ban on their use or a reduction in emissions, many contaminants can persist in the environment for decades. A decreasing trend has been observed in the concentrations of some contaminants, notably dichlorodiphenyltrichloroethane (DDT) and polychlorinated biphenyls (PCBs) (Lebeuf et al., 2007; Lebeuf, 2009). Other contaminants are either unregulated or have been regulated only recently. For example, the use of polybrominated diphenyl ethers (PBDEs) in the 1990s led to their exponential increase in beluga tissues and the environment (De Wit, 2002; Lebeuf et al., 2004).
Generally speaking, contaminants can significantly disrupt endocrine, reproductive, immune, and nervous system functioning in animal species (Martineau et al., 1987; Béland et al., 1993; Colborn et al., 1993). Some researchers suspect that contaminants contribute to the high rates of cancer and other diseases in the St. Lawrence belugas (Martineau et al., 1999; Martineau et al., 2002a; Lair, 2007), as well as alterations in the reproductive system (Martineau et al., 1988; Béland et al., 1992; Béland et al., 1993; De Guise et al., 1995; De Guise et al., 1996; Martineau et al., 2002a; Martineau et al., 2003). Between 1983 and 2006, 16% of the 175 St. Lawrence belugas that were stranded and examined had at least one terminal cancerous tumour (Table 1).
Unfortunately, toxicological studies on belugas and the identification of causal relationships are hampered by difficulties in sampling fresh tissues and conducting experiments. Although the critical thresholds at which these contaminants become toxic in belugas are not known, certain thresholds have been identified in other marine mammal species, such as the harbour seal (Ross et al., 1996). Meanwhile, the Great Lakes Water Quality Agreement, ratified by Canada and the United States, established concentration thresholds for organochlorinated compounds and mercury in prey animals to safeguard the health of fish-eating birds and mammals (International Joint Commission [IJC], 1978). PCB and mercury concentrations in some potential beluga prey have decreased in recent decades, but remain above the protection threshold for predators (Couillard, 2009). For more information about each group of contaminants, see Appendix 2.
It is important to consider that the toxicity of chemicals may also be augmented by the synergistic effect between the various contaminants. For example, De Guise et al. (1998) showed that in vitro exposure to certain mixtures of PCB congeners leads to lower production of beluga splenocytes (a type of white blood cell that plays an important role in the immune system), whereas individually and in equal concentrations, the same congeners have no discernable effect. Eriksson et al. (2006) demonstrated that PCBs and PBDEs have cumulative effects on behaviour in mice. Contaminants may also interact with other environmental factors (reviewed in Couillard et al., 2008a; Couillard et al., 2008b). For example, a reduction in prey availability at a critical time of the year could lead to the release of contaminants accumulated in the beluga's fatty tissue, and consequently increase the risk of toxic effects. Climate change and pathogens could also amplify the effects of these contaminants. Changes in temperature, pH, and salinity due to climate change could affect the toxicity and bioavailability of contaminants (reviewed in Schiedek et al., 2007).
In short, contamination in the St. Lawrence beluga population is considered a serious threat to its recovery. Despite reductions in discharges of some toxic chemicals, contaminant concentrations in beluga tissues are not decreasing very quickly. Moreover, new persistent contaminants have been introduced into aquatic habitats, and they are accumulating in beluga tissues (see Appendix 2). Belugas could therefore continue to be affected by contaminants for decades to come. Juveniles and adults continue to be exposed through their diet, and calves receive high doses directly from their mothers, which extends the time required for contamination levels to drop. Because some pathologies associated with contaminants require several years to develop (15 to 25 years), past contamination is cause for concern about the health of the current population. In addition, if contaminants are negatively affecting the reproductive system of the belugas, the already low population growth rate of the species would be further reduced.
3) Anthropogenic disturbances
Marine traffic and marine life observation activities
In order to survive and reproduce, whales must rest, search for food, eat, avoid predators, communicate and socialize with other whales, mate, and raise their calves. If these activities are disrupted, the animal cannot carry out its vital functions and its survival is jeopardized (Kraus et al., 2005; Bejder et al., 2006b; Williams et al., 2006). If the disruption is recurrent and affects several animals, then the survival of the entire population is at risk. Navigation is a source of disturbance because of the presence of vessels and the noise they generate in the beluga habitat. Marine life observation activities (MLOA) and marine traffic are potential sources of disturbance for the St. Lawrence belugas (DFO and WWF, 1995; Lesage and Kingsley, 1995; Lien, 2001). The St. Lawrence Estuary is a major shipping corridor, and in summer, an area of intense MLOA. Since the early 1980s, MLOA has grown spectacularly, and specifically in vital beluga habitats (Ménard et al., 2007). The danger of collisions with ships and other water craft is dealt with below in the section on Ship Strikes.
The St. Lawrence Seaway is an exceptionally busy shipping corridor that accommodates all vessels entering or leaving the freshwater reaches of the river and the Great Lakes. Different types of vessels travel through the territory frequented by belugas: freighters, commercial vessels, ferries (approximately 90 ferry crossings per day between Tadoussac and Baie-Sainte-Catherine), icebreakers, excursion and cruise ships, Coast Guard and Parks Canada patrol boats, National Defence ships, and research vessels. Pleasure craft, inflatable boats, and personal watercraft add to the list. Approximately 52 000 boats trips of all types were counted in the Saguenay-St. Lawrence Marine Park (SSLMP) from May to October 2007 (Chion et al., 2009). Any form of ship traffic can affect belugas, and the greater manoeuvrability and speed of smaller craft creates an additional problem (Lesage et al., 1999).
St. Lawrence belugas are susceptible to MLOA disturbance from various commercial and pleasure watercraft or aircraft (planes and helicopters). MLOA have become an important component of the regional tourism industry in the St. Lawrence Estuary (Tecsult Environnement, 2000; Lien, 2001). A study on MLOA published in 2001 revealed that over 85% of marine mammal observation tours offered in Quebec were conducted in this area (Hoyt, 2001). In 2005, more than one million people visited the SSLMP and the observation and interpretation sites around this marine protected area. (SOM, 2006). Even though belugas are not generally targeted by MLOA, monitoring of these activities using excursion boats indicated that up to 5% of MLOA specifically target belugas from mid-June to September (Michaud et al., 2003). MLOA are also concentrated in an area that contains 50% of the beluga population, and these areas are heavily used by adult females and their young (Michaud, 1993a; Kingsley, 1999; Gosselin et al., 2007).
Exposure to noise and other sources of disturbance can produce behavioural reactions such as subtle changes in diving patterns, brief or prolonged interruptions in normal activities (rest, feeding, socialization, raising young, vocalization, breathing, diving), and even short- or long-term abandonment of disturbed areas (Richardson et al., 1995; National Research Council [NRC], 2003; Bejder et al., 2006a; Weilgart, 2007). The belugas' reaction depends on the predictability of vessel transit, the approach type, and the length and frequency of the disturbance, combined with the activity level and behaviour of the belugas at the time of the disturbance (for a review, see Lesage, 1993). Blane and Jackson (1994) observed that belugas showed ship avoidance behaviour by prolonging the intervals between surface breathing, increasing swimming speed, and forming tighter groups. It has been suggested that belugas have abandoned the Bay of Tadoussac and altered their movements at the mouth of the Saguenay River as a result of increased marine traffic in that area (Pippard, 1985a; Caron and Sergeant, 1988). Although belugas retain a certain amount of fidelity even to high-use areas (Lesage, 1993), this fidelity may simply be an indication of the importance of these sites for the species and the lack of alternate sites (Brodie, 1989). In the northeast Atlantic, it has been shown that cetaceans avoid ships that use air guns for seismic surveys used to prospect for oil and gas (Stone, 2003). It has also been shown that seismic exploration causes odontocetes (toothed whales) to alter their migration routes, swimming speed, diving patterns, and feeding habits (Stone, 2003). Cases of disturbance caused by low-flying aircraft have also been recorded along the St. Lawrence (Sergeant and Hoek, 1988). The long-term effects on the beluga population of behavioural changes in response to disruption are unknown, but these disturbances may diminish their capacity to maintain the energy reserves required for successful reproduction and survival in times of food scarcity. Disruptions that cause the separation of a mother from her calf may seriously affect the calf's chances of survival and limit potential population growth. This threat is of particular concern for the St. Lawrence belugas, because whale watching activities, which increase noise and marine traffic, peak during the summer months when whales are calving and nursing.
Noise disturbance is a problem in the St. Lawrence Estuary, and is more problematic in certain sectors, for instance, at the head of the Laurentian Channel, located at the confluence of the Saguenay and St. Lawrence Rivers (Scheifele et al., 1997; Simard et al., 2006). The bandwidth of noise produced by motorized vessels is very broad, ranging from just a few Hz to over 100 kHz. The maximum energy frequency depends on the vessel's size and propulsion type. For large merchant ships navigating the Saint Lawrence Seaway, this frequency oscillates between 0.02 and 0.20 kHz, whereas the frequency for smaller craft such as inflatable boats is much higher, ranging between approximately 0.5 and 6 kHz (Richardson et al., 1995; Lesage et al., 1999; Simard et al., 2006). In any case, all vessels produce noise at higher frequencies, up to 100 kHz (Simard et al., 2006). Odontocetes produce three different types of sound: whistles, rapid sounds used for echolocation, and a variety of cries, grunts, and barks. They use these sounds to identify themselves, to coordinate their hunting, to maintain social cohesion, and to detect, locate, and identify prey and obstacles by echolocation (Richardson et al., 1995). Belugas use whistles and pulsed tonal signals for communication, generally at frequencies between 0.5 and 3.5 kHz. For echolocation, they use clicks and pulsed tones emitted at much higher frequencies, between 30 and 60 kHz (Bédard and Simard, 2006).
In the last fifty years, anthropogenic noise has increased significantly in oceans around the world. Besides all manner of ship traffic, various industrial and military activities have added to the background noise (Richardson et al., 1995; NRC, 2003; Tyack, 2008). For example, the oil and gas industry generates high noise levels in the ocean, particularly during seismic surveys, when the highest noise levels for oil and gas exploration and development activities are recorded (Richardson et al., 1995).
This higher noise level can be exacerbated by declining pH in the water column. The Intergovernmental Panel on Climate Change has released scenarios showing that the pH in the surface waters of the world's oceans will decrease by 0.3 units by 2050 (Brewer, 1997). Climate change combined with eutrophicationFootnote 5 has already created a reduction of 0.2 to 0.3 pH units in the deep waters of the St. Lawrence Estuary (M. Starr, DFO, unpublished data). Hester et al. (2008) showed that a decrease of 0.3 pH units leads to a 40% reduction in the capacity of the water mass to absorb sound at frequencies less than 10kHz. This would allow anthropogenic noise to travel greater distances and further interfere with whale communication in the Estuary.
An important effect of increased ambient noise in oceans is sound masking, which interferes with the beluga's ability to accurately echolocate and communicate with other belugas (NRC, 2003). The intensity and frequency of a sound, combined with the animal's hearing capability (auditory threshold level), determine how well that sound is heard. Species like the beluga, whose hearing is highly directional, have other means of dealing with masking (Erbe and Farmer, 1998; Mooney et al., 2008). In the presence of vessels, belugas reduce the number and variation of sounds they produce, increase the duration and intensity of certain signals, and repeat sounds more often and at frequencies that are subject to less interference from the noise of the vessel (Lesage, 1993; Lesage et al., 1999). Accordingly, higher volume sounds or else a complete cessation of vocalization have been observed in St. Lawrence belugas in the presence of high ambient noise (Lesage et al., 1999; Scheifele et al., 2005; Erbe, 2008).
Lastly, anthropogenic noise can also cause temporary or permanent changes in hearing thresholds, trigger stress hormone production, lead to physical injury such as air bubble formation due to rapid ascent to escape noise (decompression), and even result in death (Ketten et al., 1993; Crum and Mao, 1996; Evans and England, 2001; Finneran, 2003; Jepson et al., 2003; NRC, 2003). Sounds generated by marine traffic in the St. Lawrence Estuary create a disturbing level of noise pollution that threatens to injure belugas' ears, which are critically vital for communication, navigation, and hunting. Furthermore, if this noise creates chronic stress in the animal, the adverse effects could affect many functions, including reproduction, metabolism, growth, immunity, and resistance to certain diseases (Lesage, 1993; NRC, 2003; Tyack, 2008). The ears of marine mammals share structural similarities with those of other vertebrates (Fay and Popper, 2000), and several studies on different vertebrate species have demonstrated that exposure to the intense noise produced by air guns during seismic surveys could injure whales' ears if they cannot avoid the sound (reviewed by Ketten and Potter, 1999; McCauley et al., 2003; Lawson and McQuinn, 2004; Southall et al., 2007).
Little is known about the effects of marine traffic on the St. Lawrence beluga population. Elsewhere in the world, these effects have been studied in several populations of cetaceans, including dolphins, killer whales, and North Atlantic right whales (Kraus et al., 2005; Bejder et al., 2006a; Williams et al., 2006). These studies suggest that high levels of marine traffic and MLOA are a threat to the recovery of the St. Lawrence beluga. Continued monitoring of the effects of these anthropogenic activities on the beluga population is required, along with the ongoing implementation of measures designed to mitigate their impact.
4) Reduction in the abundance, availability, and quality of prey
Reduced fish abundance
In recent decades, several fish populations in the Estuary and the Gulf of St. Lawrence have declined significantly. A number of factors can be blamed for this: overfishing, habitat degradation, pollution, and barriers to migration. For example, in the Upper St. Lawrence, the abundance index for American eels that migrate upstream at the Moses-Saunders Dam was reduced by over 99% between 1980 and 2000, and total catches in the Estuary declined from 452 tonnes in 1980 to 82 tonnes in 2004 (COSEWIC, 2006). The cod population of the Northern Gulf dropped from 559 million in 1980 to 43 million in 2008 (DFO, 2009b). The Atlantic halibut, despite a marked increase in the past decade, remains at a low level compared to stocks in the first half of the 20th century (DFO, 2007). The rainbow smelt population has also declined considerably over the past 30 years (Équipe de rétablissement de l'éperlan arc-en-ciel du Québec, 2008). Despite the belugas' varied diet and their adaptability, changes in the specific composition of fish stocks in the Estuary could affect the nutritional quality and energy content of the available prey species.
Climate change could also affect fish stocks in the St. Lawrence Estuary. Currently, the water masses of the St. Lawrence are cooling as its cold intermediate layer is growing wider and colder (Galbraith et al., 2008). Changes in the abundance and distribution of certain species have been observed: the distribution area of capelin has drifted south and west, and macrozooplankton is less abundant than it was in the early 1990s (Harvey et al., 2005; DFO, 2008). Many fish species are sensitive to water temperature, which impacts their survival, spawning, and growth (Gilbert and Couillard, 1995; Minns et al., 1995; Gilbert, 1996; Gilbert and Pettigrew, 1996). Water temperature also determines the migration periods and routes of several fish species (Narayana et al., 1995). As the ice cover in the Gulf of St. Lawrence is closely related to air temperature, climatic models predict that the Gulf will be ice-free within 50 years (Dufour and Ouellet, 2007). A change in the ice cover can impact the food chain.
In the St. Lawrence Estuary and Gulf, lower proportions of well-oxygenated water of the Labrador current, combined with nutrients from agriculture, industry, and municipal waste in the Estuary, have caused oxygen concentrations in the deep waters of the Estuary to fall (Gilbert et al., 2005). Hypoxia (oxygen deprivation) affects several estuaries around the world, and usually results in significant changes in biodiversity and productivity (Diaz, 2001).
Finally, the tributaries of the Estuary and the coastal marshlands where several species of fish breed and grow have been polluted and degraded. Taken together, these changes could affect the abundance and distribution of species at every level of the food chain, including the beluga's prey.
Competition with other predators
The Gulf of St. Lawrence and the Estuary are inhabited by four seal species and 13 cetacean species (8 species of Odontocetes and 5 species of Mysticetes), including the beluga. Whereas cetaceans other than the beluga frequent the area from spring to fall, seals are either year-round residents, such as the gray seal (Halichoerus grypus) and the harbour seal (Phoca vitulina), or they are winter transients, such as the hooded seal (Cystophora cristata) and the harp seal (Pagophilus groenlandica). In winter, up to a million harp seals live in the Estuary and the Gulf (Roff and Bowen, 1983; Sergeant, 1991; Hammill and Stenson, 2005), and the resident gray seal population numbers approximately 50 000 (Hammill, 2005). Large populations of several marine bird species also compete with whales for food. These include the razorbill (Alca torda), the double-crested cormorant (Phalacrocorax auritus), the herring gull (Larus argentatus), the ring-billed gull (L. delawarensis), and the great black-backed gull (L. marinus) (Lesage and Kingsley, 1995).
Several studies have documented the distribution of food resources among species in the St. Lawrence River, but it is difficult to evaluate the degree of competition among these species. Lesage et al. (2001) showed that harbour seals and hooded seals are at the top of the food chain, while gray seals, harp seals in the Gulf, and male belugas are at an intermediate level, and the harp seals in the Estuary and female belugas are at a lower level. It may be that St. Lawrence belugas are less susceptible to competition for food resources because their diet, like the diet of other beluga populations, is diversified (opportunistic) (Vladykov, 1946; Lowry et al., 1985).
It is also possible that climate change will lead to a lengthening of the season most suitable for marine birds and animals that are not adapted to the icy conditions of the St. Lawrence, thereby increasing competition during winter (Kingsley, 2002; Measures et al., 2004). Ice cover, which determines the winter distribution of marine mammal species in the Estuary, is expected to diminish gradually (Bourque and Simonet, 2008).
Competition with commercial fisheries
In addition to potential competition from other species, belugas must compete with the commercial fishing industry for food. In the wake of recent declining stocks of certain ground fish, the growing interest in the exploitation of smaller pelagic fish, including the capelin, may intensify the current competition between belugas and other marine species in the St. Lawrence. Little is known about the effects of commercial fishing on the beluga population. Because capelin are an important prey for many marine mammals and bird species that summer in the Estuary, they are a key species for the entire Laurentian system (Ménard, 1998; Grégoire, 2005).
Note that no cases of starvation have been reported in retrieved carcasses, aside from two dead belugas found in the Saint-Paul River in 2001 (Lair, 2007). Although there is no direct proof that the recovery of St. Lawrence belugas is limited by prey availability, declining fish stocks could negatively impact this population and pose a serious threat to beluga recovery.
5) Other habitat degradation
In the summer, belugas consistently return to their summering habitats in the Estuary and the Saguenay River. This distribution pattern exposes belugas to inshore and offshore human activities such as the construction of docks, marinas, and hydroelectric dams, the expanding tourism industry, and dredging operations. An additional factor is the introduction of exotic species, which can contribute to habitat change and degradation. Certain habitat changes can become problematic for both the belugas and their food sources.
Inshore and offshore development
Construction and dredging
Shoreline projects such as the construction of harbour infrastructures, bridges, and roads can alter the beluga's environment, especially by noise pollution and the destruction of prey habitats. Each year, sediments are dredged up during maintenance operations on the St. Lawrence River's navigable waterway, in ports, and in marinas. Dredging operations designed to maintain or increase the depth and width of navigation corridors or as part of port infrastructure projects, including relatively modest projects such as marina construction, disturb the sediment and resuspend contaminants into the water column. The head of the Laurentian Channel is an area where sediment is deposited and persistent pollutants from the Great Lakes and the St. Lawrence drainage basin accumulate (Lebeuf and Nunes, 2005). Furthermore, one disposal site for dredged sediment islocated near Cacouna in beluga habitat and another one between Les Éboulements and Aux Coudres Island. However, concentrations of several contaminants in surface sediment in the St. Lawrence basin, especially in freshwater reaches, have diminished in recent decades, thanks to the deposit of a new layer of less contaminated sediment (Carignan et al., 1994; Lebeuf and Nunes, 2005). Under the Fisheries Act, each dredging project involving contaminated sediments is assessed for its impact on the fish habitat.
Dams have been built on several tributaries of the St. Lawrence River, and some can form barriers to fish migration and alter habitats used by potential beluga prey. For example, although an increasing number of migrating American eels have been observed recently going up the St. Lawrence River at the Beauharnois and Moses-Saunders dams (Bernard and Desrochers, 2007), the hydroelectric turbines of these dams are an important cause of death for mature American eels migrating downriver (Caron et al., 2007). It is also possible that physical and biological changes (in flow rates, temperature, salinity, water levels, and currents) are caused by hydroelectric installations on the estuary ecosystem downstream. The effects of such changes on belugas have not yet been documented. According to some researchers, the building of hydroelectric dams on the Manicouagan and des Outardes Rivers in the 1960s may have caused belugas to abandon the Manicouagan Banks (Sergeant and Brodie, 1975; Pippard, 1985a; Caron and Sergeant, 1988). However, other authors believe that the site was abandoned due to the decline in the beluga population following a period of intensive commercial hunting from 1965 to 1970 (Reeves and Mitchell, 1984; Michaud et al., 1990). Noise associated with the development and energy production of potential tidal power plants is also cause for concern, although no studies have yet assessed its impact on marine mammals.
Oil and gas
Seismic surveys and oil and gas developments are being carried out in coastal regions all over the world, including the east coast of Canada, east of Newfoundland and in the Scotian Shelf (Nieukirk et al., 2004). This activity creates high levels of noise in the ocean and is potentially harmful to belugas insofar as it provokes changes in behaviour, masks communication between whales, and physically impacts the hearing mechanism of the animals. Of all the stages involved in oil and gas exploration, seismic surveys create the highest level of noise (Richardson et al., 1995). Operating oil drilling platforms can also release in the environment several toxic substances such as metals, various alkyl phenols and toxic mud (Holdway, 2002; Meier et al., 2007). Seismic surveys and oil and gas developments are banned in the St. Lawrence Estuary. However, they can occur in the Gulf of St. Lawrence where belugas are likely to be present during winter.
Introduction of exotic species
The introduction of invasive exotic species is a global environmental issue. The establishment of non-indigenous species can alter the species assemblage and trophic chain of ecosystems. Although this threat is not considered serious at this time, as a precautionary measure, it is necessary to prevent the introduction of new species.
Ballast waterFootnote 6 discharge can introduce exotic species into the waters of navigation corridors. The ballasts, hulls, and sea-chestsFootnote 7 of foreign ships entering the St. Lawrence River contain assemblages of living organisms (including non-indigenous taxa, toxic or pest taxa, and potentially threatening taxa) from all over the world (Gauthier and Steel, 1996; Bourgeois et al., 2001; Simard and Hardy, 2004). The invasive exotic species found in the St. Lawrence basin are primarily freshwater species. Nevertheless, it is possible that certain invasive species could colonize environments to the detriment of the beluga's prey species.
The American Coast Guard Regulations, the Ballast Water Control and Management Regulations (2006) of Transport Canada, and the Canadian ballast water management guidelines require all ships entering Great Lakes ports from outside the exclusive economic zone to change their ballast water at sea. These regulations reduce the risk of introducing exotic species into the Great Lakes and St. Lawrence ecosystem through ballast waters.
Current threats to individual whales
This section describes the threats that disturb or kill only a small number of whales each year, but which cumulatively increase the mortality rate in a population with low recruitment.
6) Ship strikes
The St. Lawrence Estuary is used by an increasing variety of vessels, and the threat of ship strikes by belugas is correspondingly high. Although ship strikes can be fatal, they can also wound belugas, thereby reducing their survival rate. This danger is magnified by the occasionally risky behaviour of belugas, such as approaching vessels out of curiosity and engaging in playful behaviour close by (Blane and Jackson, 1994; DFO, 2002).
Belugas are probably at greater risk for ship strikes with tourist vessels and pleasure craft, which travel at higher speeds and in unpredictable directions. Since 1992, Parks Canada has compiled all cases of injury reported within the SSLMP (Laist et al., 2001). Since the entry into force of the Marine Activities in the Saguenay-St. Lawrence Marine Park Regulations, all ship strikes must be reported. In addition, from 1983 to 2006, the carcass monitoring program identified in 11 belugas different types of trauma (including cutaneous lacerations, internal haemorrhages, and fractures) that were probably caused by ship strikes (Lair, 2007; Database of the Canadian Cooperative Wildlife Health Centre). However, it was not confirmed whether ship strikes were the main cause of the deaths or whether a disease could have made these individuals more susceptible to collision. Several belugas in the St. Lawrence Estuary have injuries or scars that may be attributable to ship strikes (R. Michaud, Groupe de recherche et d'éducation sur les mammifères marins [GREMM], unpublished data). In fact, these markings are used to differentiate belugas in photo-identification surveys.
Laist et al. (2001) analyzed historical data on ship strikes involving baleen and sperm whales. They showed that juveniles are particularly vulnerable because they spend more time near the surface and lack the experience to avoid ships. Furthermore, Blane and Jackson (1994) showed that juvenile belugas interact more with vessels than adults do. Belugas have a highly developed hearing capacity and an excellent echolocation system that help them detect ships. However, anthropogenic noise (from ships, sonar, and seismic surveys) can cause hearing impairment, making it harder to detect approaching vessels, thereby increasing the risk of collision. Unfortunately, injuries to the auditory mechanism are difficult to identify in a necropsy due to the decomposition of the carcass and other interfering factors (Faulkner et al., 1998; Measures, 2007a).
7) Entanglement in fishing gear
Fishing activities, especially when fixed gear or gillnets are used, are a potential cause of death for the St. Lawrence Estuary beluga. Once a beluga becomes entangled in fishing gear, it may injure itself, develop an infection, or even die of anoxia (lack of oxygen). There is not much fishing activity in the St. Lawrence Estuary, and gillnets are rarely used. Only a few cases of belugas being caught or entangled in fishing gear or other rope have been reported. In Quebec, five cases of entanglements have been reported since 1979 (DFO and WWF, 1995; Incident Recording System, Parks Canada; L. Measures, DFO, unpublished data). The risk of entanglement in fishing gear is greater when whales venture out of their regular distribution range into areas of greater fishing activity. Between 1979 and 1991, there were several reports of belugas tangled in gillnets or cod traps off the coast of Newfoundland and Labrador (Curren and Lien, 1998). Ghost fishingFootnote 8 poses an additional potential threat. Of the 30 000 gillnets set every year in Quebec, between 600 and 2 000 are abandoned or lost. In 1991, in an effort to recover lost fishing gear, 28 172 metres of net were retrieved from the waters between Matane and Forillon (Drolet, 1998). A similar operation was carried out in Côte-Nord in 2005, where a substantial number of nets were removed from the water (Laberge, 2005).
Accidental entanglement in fishing gear does not appear to be a limiting factor for the recovery of the St. Lawrence beluga population. Very few belugas bear scars caused by fishing gear (DFO and WWF, 1995; Lair, 2007). The echolocation skills of these odontocetes may allow them to detect the presence of fishing gear and avoid entanglement. However, given the low recruitment rate of this population, any source of mortality is cause for concern.
8) Scientific research
Because it has been listed as a threatened species, the St. Lawrence beluga has been the object of many scientific studies. Fisheries and Oceans Canada, Parks Canada, various universities, and the GREMM have studied diverse aspects of the St. Lawrence Estuary beluga population for many years. Studies use data logger tags, photo identification, biopsies, and herd monitoring from boats and from the coast. Although information gathering would benefit the recovery of St. Lawrence belugas, these research projects are liable to disturb the animals. For example, boats must approach the whales to within 25 m to take photographs to identify individual animals, and within 10 m to perform biopsies using a dart shot from a crossbow (for a description of sampling methods, see Michaud, 1996).
Before any scientific study liable to disrupt marine mammals can be undertaken, a permit from DFO must be obtained, and if the research is to be conducted in the SSLMP, a permit from Parks Canada is also required. In order to obtain a permit, the research protocols and potential effects must be evaluated by an animal care committee established according to the requirements of the Canadian Council on Animal Care.
Occasional and sporadic threats
The following threats are occasional, arising only at particular times and places. However, when they do occur, they can cause the death of a significant number of belugas and threaten their recovery.
9) Toxic spills
Many ships traveling through the St. Lawrence Estuary carry petroleum products and other toxic substances. The prevailing oceanographic conditions in the Estuary and Gulf, such as very strong tides and currents, the presence of ice, and the high frequency of fog, combined with continuous marine traffic through the St. Lawrence Seaway, increase the risk of accidents. To date, there have been very few major spills in the St. Lawrence, and most of those have occurred in ports (Villeneuve and Quilliam, 1999). Nevertheless, oil exploration and development can considerably increase the risk of accidents and spills (Kingston, 2005). For example, in November 2004, a large oil spill offshore of St. John's, Newfoundland, was caused by equipment breakdown on a drilling platform. Avian and marine fauna within a radius of 5 km were affected by the spill. In addition, on April 20, 2010, an oil drilling platform in the Gulf of Mexico exploded, causing a major oil spill. The well, located at a depth of 1.5 km, spewed out approximately 780 million litres of oil into the Gulf over 11 weeks. The oil reached the coastlines of Louisiana, Alabama, and Florida. Given the relatively limited habitat available in the St. Lawrence Estuary and Gulf, a large oil spill poses a serious risk for the beluga population.
The top layer of the beluga's skin provides an effective barrier against harmful substances, and may provide some protection from oil slicks (Geraci, 1990). Nevertheless, oil spills may still pose a risk for marine mammals due to the toxic vapours that emanate from crude oil, or volatile distillates, which can damage sensitive tissue such as eye, mouth, and lung membranes (Geraci and St. Aubin, 1990). Marine mammals can also ingest spilled material or its metabolites directly or indirectly in contaminated prey. Matkin et al. (2008) have shown how the increased mortality of killer whales off the coast of Alaska was directly linked to the Exxon Valdez oil spill of 1989. The risk of contact increases in winter because oil tends to accumulate along the edges of the ice cover, where belugas spend much of their time. Site fidelity, which is well documented in St. Lawrence belugas, could also be a factor, as it brings the whales in proximity to oil slicks. Furthermore, toxic spills could have long-term consequences on the Estuary ecosystem, for example, by reducing prey abundance through higher fish mortality or through the degradation of spawning and feeding areas (Peterson et al., 2003). Climate change is expected to produce more frequent and severe extreme weather conditions, which could in turn increase the risk of toxic spills. This threat is therefore considered very dangerous for the St. Lawrence beluga population.
10) Harmful algal blooms
In the summer of 2008, a red tide covering 600 km2 appeared in the St. Lawrence Estuary. It was thought to have caused the death of 10 belugas. Proliferation of the toxic alga Alexandrium tamarense was responsible for the death of several cetaceans, dozens of seals, and thousands of birds, invertebrates, and fish (Database of the Canadian Cooperative Wildlife Health Centre). The neurotoxin produced by this alga, saxitoxin, causes paralysis in animals, including in the respiratory system, ending in asphyxia. Belugas ingest this neurotoxin through their prey. The effect of chronic exposure to saxitoxin on the health of belugas is unknown. The increase in scope of this natural phenomenon is probably due to the particularly abundant precipitation during the summer of 2008 (M. Starr, DFO, unpublished data). Eutrophication, climate change, and the ensuing change in rainfall regime may lead to an increase in harmful algal blooms, which would be a serious threat to St. Lawrence belugas. There is evidence that the frequency and geographic distribution of toxic algal blooms are increasing worldwide (Van Dolah, 2000). Although the explanations for this increase and its effects on marine mammals are still unclear, high mortality rates are increasingly associated with algal blooms (Scholin et al., 2000).
11) Epizootic disease
Many factors (small population, gregarious behaviour, limited distribution area, isolation from neighbouring populations, and depressed immune system owing to chronic exposure to contaminants) have combined to make the St. Lawrence belugas more vulnerable to infectious diseases that can become epizooticFootnote 9. A variety of marine mammal species share the relatively restricted habitat of the Estuary, living there permanently or migrating through. They are therefore liable to be exposed to a large number of pathogens (Measures, 2007b). Some of these pathogens are contained in sewage waste or runoff from agricultural land and boats (Measures and Olson, 1999). In addition, climate change could amplify the impact of these pathogens on the St. Lawrence beluga population. Global warming could increase pathogen survival during winter or lead to an influx of new marine mammal species into the Estuary, which would expose belugas to more exotic pathogens (DFO, 2002; Measures, 2004; Burek et al., 2008; Measures, 2008). Moreover, the immune system of belugas may be weakened by contaminants and stress caused by human activity (De Guise et al., 1996; De Guise, 1998), reducing their resistance to pathogens and parasites. Juveniles, with their underdeveloped immune system, are most at risk, which could greatly affect recruitment levels.
Epizootic diseases are caused primarily by viruses. The MorbillivirusFootnote 10 poses a particular threat to the St. Lawrence belugas, having caused the death of somewhere between hundreds and thousands of seals and whales worldwide in recent years. The Morbillivirus is particularly dangerous because it very rapidly reaches epidemic proportions, causes broncho-pneumonia and encephalitis, and generally results in death (Kennedy, 1998; Di Guardo et al., 2005). Belugas can become infected with the Morbillivirus through contact with terrestrial or marine mammal carriers (Mamaev et al., 1996; Barrett, 1999). If the St. Lawrence belugas were to become infected with the Morbillivirus virus, to which they have never been exposed, the consequences could be disastrous for the population: their gregariousness would facilitate propagation of the virus, and given their restricted distribution area, a great number of whales would be exposed to infection (Nielsen et al., 2000).
Other pathogens, such as the Brucella bacteria and the protozoa Toxoplasma gondii, can cause infectious diseases in belugas (Measures, 2007b). Brucellosis is a concern because it affects the reproductive system, causing mastitis, abortions, neonatal mortality, and infertility (Tryland, 2000; Nielsen et al., 2001). Despite the presence of several pathogens in the St. Lawrence beluga population, no severe epizootic outbreak has been reported.
Albeit hypothetical for the time being, the threat of epizootic disease remains worrisome because a reduced St. Lawrence beluga population would be vulnerable to extinction in the case of an outbreak. Due to the risk of transmitting exotic pathogens to the St. Lawrence beluga, there is currently a moratorium on the rehabilitation of marine mammals in Quebec, particularly seals (Measures, 2004, 2007a).
1.6 Actions already completed or underway
1.6.1 Protective laws and regulations
International legal protection
The beluga is listed as a vulnerable species by the International Union for Conservation of Nature, and it is protected under the Convention on International Trade in Endangered Species of Wild Flora and Fauna (CITES). The signatory countries, including Canada, monitor international trade in products derived from wild animal and plant species in order to ensure the survival of these species. In Canada, CITES is administered and enforced under the Wild Animal and Plant Protection and Regulation of International and Interprovincial Trade Act. The St. Lawrence Estuary beluga population is listed in Schedule II of the Convention, which stipulates that a permit is required to import or export a beluga specimen.
Federal and provincial legal protection
Hunting of the St. Lawrence beluga has been prohibited since 1979 by the Beluga Protection Regulations (1979) under the Fisheries Act (1985). In 1993, these regulations were replaced with the Marine Mammal Regulations (1993), and the regulations concerning marine mammal observation in Canadian waters became more specific. These regulations stipulate that it is unlawful to disturb a marine mammal. The Regulations are currently being revised with a view to adapting them to the different regional requirements across Canada. The Fisheries Act protects marine mammal habitat by prohibiting the carrying out of works or undertakings that may entail the alteration, disruption, or destruction of fish habitat, which, as defined by the Act, includes marine mammal habitat. In addition, section 36 of the Fisheries Act is designed to control the introduction of toxic substances into the habitat. Additionally, according to DFO's internal policy, fishing with mobile gear is not allowed in the Upper Estuary and the Saguenay Fjord. Although not specifically aimed at protecting belugas, this measure provides some protection for its prey.
Moreover, since 2005, the St. Lawrence Estuary beluga population has been listed as a threatened species under the Canadian Species at Risk Act. Consequently, it is prohibited to kill, harm, harass, capture, or take any individual animal of this species, or to damage or destroy the residence of one or more individuals. The Act also prohibits the destruction of any part of the critical habitat of the species.
The regional community's concern to protect the beluga and its habitat was a determinant factor in the creation of the Saguenay–St. Lawrence Marine Park (SSLMP) (Figure 7). The Marine Park was officially established on June 10, 1998 under the so-called "mirror" laws enacted by the Canadian and Quebec government, the Saguenay–St. Lawrence Marine Park Act and the Act respecting the Saguenay–St. Lawrence Marine Park. The Marine Park, which spans 1245 km2, is administered jointly by the two governments, through Parks Canada and the Ministère du Développement durable, de l'Environnement et des Parcs du Québec (MDDEP). The Marine Activities in the Saguenay-St. Lawrence Marine Park Regulations (2002) are derived from the federal Act. These Regulations set out protective measures for endangered or threatened species, for example, prohibiting any approach within 400 m of the animal. In addition, the number of tour boats allowed to operate as well as their speed and length of stay at the observation sites within the Park are limited and controlled by a permit system. Seismic surveys and oil and gas development are prohibited within the Park under provincial law.
The SSLMP regulations also call for the implementation of zoning. Zoning will be a vital management tool to achieve conservation objectives and ecologically sustainable use of the Marine Park. In 2006, the Sainte-Marguerite Bay Beluga Whale Committee was formed with a mandate to define protective measures for this habitat and implement actions to preserve the bay, an important summering ground for the beluga. In 2008, a management plan for marine activities was initiated in the Marine Park. Both projects aim in particular to develop specific management strategies for marine activities in the Marine Park, which is an important beluga habitat as well as a site of considerable vessel traffic of all kinds.
Furthermore, the beluga could be protected by Canadian and Quebec laws providing for the creation of marine protected areas (MPAs) in the future. The Oceans Act (1996) gives DFO the authority to establish MPAs in order to protect one or more components of an ecosystem where species are at risk. Quebec's Natural Heritage Conservation Act (R.S.Q. chapter C-61.01) grants the MDDEP the authority to designate protected areas in its territory in order to protect the diversity and important components of the marine ecosystem. Since 2007, the Bilateral Group on Marine Protected Areas (BGMPA) made up of representatives from the two governments has coordinated efforts to establish a network of marine protected areas in Quebec. This group is currently working to develop an MPA approximately 500 km2 in size in the Manicouagan sector. This proposed MPA will cover the territory that the beluga occupies from fall to spring. In the past, belugas occupied this territory in summer. A protected marine space around the Manicouagan peninsula will ensure good quality habitat for belugas from the St. Lawrence should they widen their summer distribution area. The BGMPA will then examine the St. Lawrence Estuary Marine Protected Area Project, which covers a 6000 km2; area adjacent to the SSLMP and is occupied by belugas in summer (Figure 7). This project specifically aims to protect and conserve marine mammals, their habitats, and their food sources over the long term, while maintaining sustainable economic activities. The area under consideration covers the sector where human pressures on marine mammals (MLOA, maritime traffic) are the strongest outside the Marine Park.
Figure 7. Map of the Saguenay-St. Lawrence Marine Park and the two proposed marine protected areas (MPAs), the proposed Manicouagan Aquatic Reserve and the proposed St. Lawrence Estuary Marine Protected Area.
Description of Figure 7
Map of the Saguenay-St. Lawrence Marine Park and the two proposed marine protected areas (MPAs), the proposed Manicouagan marine protected area (at the mouth of the Manicouagan River) and the proposed St. Lawrence Estuary Marine Protected Area (from the Battures des Loups Marins to Métis-sur-Mer). Inset: the location of the sector in Quebec.
Other federal regulatory or legislative measures to control activities liable to impact the St. Lawrence Estuary beluga population include the 2001 Canada Shipping Act, the Canadian Environmental Assessment Act (1992), and the Canadian Environmental Protection Act (1999). Certain provisions in the 2001 Canada Shipping Act provide the framework for the activities of a Regional Response Team, whose role is to initiate cleanup operations in case of a spill. Environment Canada, DFO, the Ministère des Ressources Naturelles et de la Faune du Québec, and some non-governmental organizations are required to work together to rescue animal species in case of a spill. The SSLMP has developed its own emergency response plan in cooperation with emergency coordination agencies (Auger and Quenneville, 2001). Response capabilities to an accidental oil spill in the Saguenay Fjord were tested and a number of recommendations were issued (Dinel and Duhaime, 1997; Auger and Quenneville, 2001). However, implementing an effective contingency plan to preventing belugas from being exposed to toxic spills is a challenge, given the numerous constraints in real situations.
The Statement of Canadian Practice with respect to the Mitigation of Seismic Sound in the Marine Environment (in PDF Format, 388 KB) specifies “the mitigation requirements that must be met during the planning and conduct of marine seismic surveys, in order to minimize impacts on life in the oceans. These requirements are set out as minimum standards, which will apply in all non-ice covered marine waters in Canada”.
St. Lawrence belugas are also protected under the Act respecting threatened or vulnerable species (L.R.Q., c.E-12). Other provincial laws can contribute to the protection of belugas, particularly by controlling pollutant emissions: the Environment Quality Act (L.R.Q., c. Q-2), the Act respecting the conservation and development of wildlife (L.R.Q., c. C-61.1), and the Water Act (L.R.Q., c. R13).
1.6.2 Water quality improvement programs in the St. Lawrence estuary
In 1972, the Quebec Legislature passed the Environment Quality Act (EQA). In 1978, as part of the EQA, the government launched a wastewater treatment program called the Programme d’assainissement des eaux du Québec (PAEQ). This program invested almost seven billion dollars into the construction of municipal sewage treatment plants across the province. The PAEQ also required industries not linked to municipal sewage plants to build their own wastewater treatment facilities. The result was a significant decrease in wastewater discharge into waterways across the province. The Programme de réduction des rejets industriels, or industrial waste reduction program, also a part of the EQA, targets Quebec’s main industrial sectors in an attempt to reduce polluting emissions. In 1988, the Quebec and Canadian governments joined both efforts and investments to launch the St. Lawrence Action Plan (SLAP) in an attempt to clean up the St. Lawrence River. The primary objective was the elimination of chemical pollution from the river. Fifty major enterprises were targeted and required to reduce their toxic liquid waste by 90% over five years. In 1993 and 1998, two new phases of the program were initiated, called St. Lawrence Vision 2000, in which 56 more plants were added to the priority list for reducing toxic emissions. At the end of this campaign, measurable improvements were noted and concrete measures had been taken, and most of the targeted plants reduced their toxic effluents (Dartois and Daboval, 1999). Among others, the SLAP led to a reduction in polycyclic aromatic hydrocarbon (PAH) emissions from aluminum smelters, which led in turn to lower concentrations of these contaminants in the surface sediments of the Saguenay River (Gearing et al., 1994; White and Johns, 1997). In addition, Priority Intervention Zone (PIZ) Committees were set up during the second phase. The action plan also includes strategies for biodiversity conservation, clean agricultural practices, public protection, and the management of water levels and ship traffic. The discharge of toxic chemicals has decreased immensely since the implementation of the PAEQ, the SLAP, and the application of regulations for the reduction of polluting emissions from pulp mills and refineries (Rondeau, 2002; Painchaud and Villeneuve, 2003; Pelletier, 2005).
Furthermore, in 1996, a committee was formed to define issues in contaminated aquatic sites and to identify sites requiring immediate attention due to their impact on the St. Lawrence beluga. Based on the information available at the time, they identified 38 sites where high toxic chemical concentrations in sediment posed a potential threat to belugas (Gagnon and Bergeron, 1997).
Several Canadian and American programs have been set up to improve water quality in the Great Lakes, which flow into the St. Lawrence: the Canada-Ontario Accord, the Great Lakes Water Quality Accord, the Great Lakes Binational Toxics Strategy, the federal Great Lakes Program, and Lakewide Management Plans. Canada has also made international commitmentsFootnote 11 to effectively control the trade of hazardous chemical products.
1.6.3 Ban on oil and gas exploration and development
Following a 2004 Bureau d'audiences publiques sur l'environnement (BAPE) inquiry and public consultation concerning seismic surveys and a strategic environmental assessment, started in 2009 to assess the environmental, social, and economic issues surrounding oil and gas exploration and development in the St. Lawrence Gulf and Estuary, the Government of Quebec banned drilling in the lower estuary and northwest Gulf of St. Lawrence. This ban covers the greater part of the St. Lawrence beluga’s distribution area.
Quebec Marine Mammal Emergency Response Network (QMMERN)
From 1982 to 2002, DFO and the SLNIE monitored stranded marine mammals in the St. Lawrence Estuary. Groupe de recherche et d'éducation sur les mammifères marins (GREMM) took over this project in 2003, and in 2004 created the Quebec Marine Mammal Emergency Response Network to help distressed animals, in collaboration with thirteen partners, including DFO and Parks Canada. The mandate of this network is to organize, coordinate, and implement measures to reduce accidental marine mammal mortalities, to rescue distressed animals, and to gather information from animals that are dead, stranded, or adrift in the Quebec waters of the St. Lawrence. GREMM coordinates the network and runs the call center.
Awareness raising at the SSLMP
Each year, the SSLMP offers a training course for tour boat operators to familiarize them with good practices in marine mammal observation (including the regulations for activities at sea, biology, and tips on how to diversify tours). Since 2008, this course has been mandatory for anyone wishing to obtain a permit to operate in the Park. Parks Canada plans to expand this training to cover kayaking guides and naturalists. Parks Canada and Parcs Québec are also carrying out a number of initiatives in the park, such as educational tours and patrols designed to raise the awareness of recreational boaters about Park regulations. A pamphlet outlining the current Park regulations is also available to the general public. In 2007, DFO and Parks Canada, in collaboration with the marine mammal observation industry, published guidelines for best practices for watching marine mammals in Quebec.
Habitat Stewardship Program
Several different projects have been initiated as part of the Canadian Habitat Stewardship Program (HSP) for Species at Risk:
- In 2003, the PIZ Committee for the north shore of the Estuary created a network for shore-based whale observation and interpretation sites. An awareness project was also initiated to inform kayakers of appropriate boating behaviour around endangered marine mammals.
- The Marine Mammals Ecowatch Network has launched an awareness project to encourage tourism employees and directors to rethink their approach to whale watching activities. The Network has been monitoring MLOA in Gaspésie since 2006, and has been visiting public schools since 2005 to raise youth awareness of endangered species.
- The Corporation PARC Bas-Saint-Laurent has designed and implemented a school program to raise awareness of marine mammals.
- GREMM publishes a weekly newsletter called Whale Echo during the tourist season. Aimed at boat captains and naturalists, it provides the latest news on current projects and initiatives to protect whales.
- The coordination centre for the QMMERN also receives support from the HSP.
1.6.5 Measures to mitigate disturbance by scientific activities
There are many ways of minimizing disturbance to belugas during field surveys, for example, reducing speed when approaching a herd, waiting 15 minutes before approaching a herd within 300 m, working close to a herd for a maximum of three hours at a time, and not taking biopsy samples from groups that include calves. In studies on the effects of biopsy sampling on beluga behaviour, it was found that whales that were shot with a dart would generally make a sudden dive, followed by the accompanying herd of whales. Fifteen to 20 minutes later, however, the targeted whale, along with the rest of the herd, seemed to exhibit no after-effects of the dart, and were as easily approachable as before (Michaud, 1996; De la Chenelière, 1998).
In addition to the beluga carcasses monitoring program, several research groups from different programs are studying St. Lawrence Estuary belugas. The following is a non-exhaustive list of these research programs:
- In order to monitor population size and trends, aerial surveys have been carried out every two or three years, since 1988, by DFOscientists.
- For several years now, Parks Canada has been conducting a beluga observation research project at two sites in the SSLMP (Pointe Noire, at the mouth of the Saguenay River, and Sainte-Marguerite Bay) to better understand the beluga’s use of these sectors and to assess marine traffic intensity. The collected data will be used to develop a management plan for marine activities in these areas. A portrait of navigation in the SSLMP was completed in 2007. In 2009, a study on beluga prey in high-use areas was initiated.
- GREMM has been conducting research on the distribution and social organization of belugas, using photo-identification, biopsies, and close monitoring of herds over a 20-year period. A project to study marine life observation activities conducted by GREMM and Parks Canada since 1994 was expanded with the participation of DFO in 2005. The research project aims to characterize MLOA, assess the distribution of marine animals, and eventually develop regulations and evaluate the impact of current management measures in the SSLMP and the proposed MPA in the St. Lawrence Estuary.
- Since 2001, GREMM and DFO, in collaboration with Parks Canada, have carried out a joint study on beluga diving patterns and movement in the Estuary to better understand their use of the habitat.
- Since 2004, DFO and the Department of National Defence have conducted a joint study of the intensity of noise pollution to which belugas are exposed in different habitats.
- Since 2004, DFO has monitored whale distribution in the St. Lawrence Estuary and used a computerized continuous hydrophone system to assess their exposure to noise. The objective is to characterize the use level of beluga habitats through acoustic analysis and to understand the processes behind the creation and maintenance of an important and regularly frequented habitat for the St. Lawrence belugas: the mouth of the Saguenay River.
- The University of Connecticut, in collaboration with GREMM, DFO, Parks Canada, the Department of National Defence, and Park Foundation, is conducting a research program to evaluate the effects of noise pollution on this threatened population.
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