Management Plan for the Banded Killifish, Newfoundland Population, in Canada [Final] 2011: Species Information
Common Name (population): Banded Killifish (Newfoundland Population)
Scientific Name: Fundulus diaphanus
COSEWIC Status: Special Concern
Reason for Designation: The population is separated from others by a major barrier to movement, i.e. 200 km of ocean. The Newfoundland population has a very limited area of occupancy. The possibility of range expansion is limited by steep gradients and impassible rapids and/or falls. Habitat degradation resulting from proposed logging would negatively impact the population in some areas.
Canadian Occurrence: Newfoundland
COSEWIC Status History: Last assessment based on updated status report
The Banded Killifish is a member of the family Fundulidae, which contains five genera and approximately 48 species (Nelson, 1994). Of these, only Fundulus diaphanus and F. heteroclitus (Mummichog) are native to Newfoundland (Scott and Crossman, 1964, 1973; Houston, 1990). The Banded Killifish is divided into two subspecies; Fundulus diaphanus diaphanus (Lesueur), the eastern Banded Killifish, and F. diaphanus menona (Jordan and Copeland), the western Banded Killifish (Chippett, 2003), the former of which is found in Newfoundland.
The Banded Killifish has olive coloured sides with numerous vertical bands and a contrasting dark colouration across the dorsal region (see cover illustration). These vertical bands in females usually appear black in colour, are thin and distinct, and often do not appear to span the full width of the body. Males have pale, grey bands that are less distinct and closer together. Adult Banded Killifish are usually small, with mean length ranging from 73.2 mm (Freshwater Pond) to 91.9 mm (Loch Leven) within the Newfoundland population sampled (Chippett, 2004). A measurement of 128 mm taken from the Indian Bay watershed is likely the largest recorded length for the species (Chippet, 2003).
Banded Killifish can live to a maximum of 4 years of age and reach maturity at an age of 1+ years and at a length of approximately 60 mm (Carlander, 1969). These fish fertilize eggs externally and spawn on plants. Females lay eggs equipped with adhesive threads that adhere to aquatic vegetation once released. Banded Killifish in the Indian Bay watershed were observed exhibiting spawning behaviour in late June through to the middle of August, when water temperatures reached 19-23oC (Chippett, 2003).
It should be noted that there are two species of Killifish in Newfoundland waters, the Banded Killifish (Fundulus diaphanous)and the Mummichog (F. heteroclitus). They are very similar in appearance and size and are often found schooling together. Due to these factors, it may be difficult to distinguish between them, leading to misidentification of the Banded Killifish species. This could potentially alter the results of surveys and population monitoring.
Banded Killifish are distributed throughout eastern North America, extending as far south as South Carolina and as far north as the provinces of Atlantic Canada. Their westward distribution extends through the states of New York, Pennsylvania, and to southern Canada in the Great Lakes region as far west as the Yellowstone River in eastern Montana (Scott and Crossman, 1973; Houston, 1990). The Newfoundland population represents the easternmost extent of this species' range. The known locations where Banded Killifish occur in Newfoundland have been documented (Chippett, 2003) (Appendix 3, Fig. 1). The majority of these are clustered on the south and southwest coasts, with an outlier in the Indian Bay watershed in the northeast (Chippett, 2003). Genetic investigations indicate that the Newfoundland population does not differ genetically from mainland populations (Chippett, 2004).
Banded Killifish in Newfoundland are scattered over a wide range, but are frequently restricted to very confined regions within their respective watersheds. They appear to be locally abundant in the representative locations that were sampled (i.e. Indian Bay watershed, Loch Leven and Freshwater Pond). Although multi-year data is not available, population estimates from 1999 indicate that over 20,000 individuals exist in the Indian Bay watershed. Estimates are not available for other locations (Chippett, 2003). Additional population information, including catch per unit effort in three sites is outlined in Chippett (2004).
Banded Killifish are a euryhaline species and are relatively poor swimmers with limited sustained and burst swim speeds (Blair Adams, Regional Ecologist, Department of Natural Resources, Pers. Comm.). Their preferred habitats are lakes, slow current areas of larger streams or rivers (Fritz and Garside, 1974, 1975), and quiet areas of estuaries (Blair Adams, Regional Ecologist, Department of Natural Resources, Pers. Comm.). Banded Killifish are most often observed in the shallows and quiet areas of clear lakes and ponds with a muddy or sandy substrate, high detrital content and abundant submerged aquatic vegetation (Trautman, 1957; Scott and Crossman, 1964, 1973; Houston, 1990). Qualitative examinations of lakes where this species occurs in Newfoundland are consistent with accounts describing Banded Killifish habitat elsewhere. A full quantitative and qualitative description of Banded Killifish habitats sampled in Newfoundland is available in Chippett (2004). More recent observations of Banded Killifish indicate that their use of estuarine habitat in Newfoundland may be more important than previously thought (Chuck Bourgeois, Section Head, Salmonids, DFO, Newfoundland and Labrador Region, Pers. Comm.).
The Banded Killifish can feed at all levels within the ecosystem (Keast and Webb, 1966), but generally feed on benthos and to a lesser extent on flying insects (Chippett 2003, Scott and Crossman 1973). When locally abundant, Banded Killifish can be an important food source for piscivorous fish and birds. In Newfoundland, this would make them an important forage fish for larger species including Brook Trout (Salvelinus fontinalis), Atlantic Salmon (Salmo salar), American Eel (Anguilla rostrata), Brown Trout (Salmo trutta) and Rainbow Trout (Onchoryncus mykiss). Other predators include the Belted Kingfisher (Megaceryle alcyon) and Common Merganser (Mergus merganser) (White, 1953, 1957; Scott and Crossman, 1973).
Documented locations of Banded Killifish in Newfoundland are fragmented and therefore there is little or no interaction among these groups. The nature of this distribution suggests that the Newfoundland population may be especially vulnerable to long-term catastrophic events or localized perturbations. However, Banded Killifish appear to have very high reproductive rates and relatively short population doubling times (Jones et al., 2008). This suggests that they may be resilient to short-term perturbations or catastrophic events such as heat or ice kills (Blair Adams, Regional Ecologist, Department of Natural Resources, Pers. Comm.).
Obstacles, such as steep river gradients and physical barriers (both natural and anthropogenic), prevent inland migration and access to additional suitable habitat. Suitable habitat, in terms of substrate type and aquatic vegetation, is thought to be abundant in Newfoundland (particularly in the central region) but may be inaccessible to this species due to these difficult migration routes. However, in some locations where Banded Killifish were restricted in distribution to one or two lakes (e.g. Indian Bay watershed), abundant suitable habitat in adjacent lakes linked by easily passable brooks and streams showed no evidence of Banded Killifish presence (Chippett, 2003).
Banded Killifish are often found in estuaries, using both brackish and fully marine habitats. This suggests some capacity for dispersal and migration between watersheds and along the coast (Blair Adams, Regional Ecologist, Department of Natural Resources, Pers. Comm.). Chippett (2003) suggests that this species has had little success in dispersing throughout the watersheds due to long stretches of deep, open water where predation by larger fish species would be substantially higher than would be the case in the weedy shallows.
COSEWIC (2003) indicated that suggested limiting factors, such as low water temperatures and the availability of suitable habitat (Gibson et al., 1984; Houston, 1990), are likely not limiting to Banded Killifish in Newfoundland. Spawning has been observed in the Indian Bay watershed at temperatures of 19-23oC, a range which is available throughout most of the island (Chippett 2003). Chippett (2004) noted that suitable habitat, in terms of both substrate type and aquatic vegetation, is readily available throughout most regions of Newfoundland. However, while freshwater habitat may be abundant it lacks connectivity and this impacts distribution (Chuck Bourgeois, Section Head, Salmonids, DFO, Newfoundland and Labrador Region, Pers. Comm.). Banded Killifish can move along the coast but their ability to inhabit many watersheds is going to be determined by the velocity in the lower reaches of streams and whether there is suitable habitat in the estuaries. There are few estuaries around the coast of Newfoundland with low velocity, vegetation and a detritus bottom. This may therefore be a limiting factor for the species (Chuck Bourgeois, Section Head, Salmonids, DFO, Newfoundland and Labrador Region, Pers. Comm.).