Short-tailed albatross (Phoebastria albatrus) COSEWIC status report: chapter 13

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Summary of Status Report

The Short-tailed Albatross Phoebastria albatrus breeds on only two islands south of Japan, but ranges throughout the North Pacific Ocean. While the species once numbered in the millions, feather hunting in the early 20th century drove the species to near extinction. The most recent estimate of population size is 1600 individuals. There are no numerical estimates of uncertainty available for this estimate. The overall population trend is one of steady increase, with breeding populations increasing by 7-11% annually.

This current growth rate is likely due to the extremely low population size compared with historical abundance. As the populations increase, density dependence could impact many of those demographic rates included in this report. For example, age of first breeding may increase, or fledging rates may decrease. However, it is likely to take many years for populations to reach these levels (Cochrane and Starfield 1999). 

The greatest threats to the species recovery are volcanic eruptions and incidental mortality associated with the longline fishing industry. They are not mutually exclusive. Oil fouling represents a significant potential threat. Additional impacts include those from plastics pollution and introduced species; however, these remain unquantified. Because the population size is small, and breeding is limited to only two colonies, a catastrophic volcanic (or weather) event on Torishima has the potential not only to significantly reduce the numbers of birds, but also to significantly reduce the worldwide breeding population to a level where the risk of extinction is high. This risk is buffered by adult and immature non-breeding birds that remain at sea during the breeding season. While significant, incidental mortality in the longline fishing industry is not viewed as the major threat to the species’ survival at the current population and growth rate. However, because it does represent an increase in the natural mortality rate, the incidental take of Short-tailed Albatrosses has the potential to slow the species conservation and recovery in the case of a random stochastic event such as a volcanic eruption or major oil spill.

Of the risks outlined above, incidental mortality in the longline fishing industry represents the greatest ongoing threat to the continued and increasing occurrence of the Short-tailed Albatross within Canada waters. Black-footed Albatrosses are routinely killed in commercial halibut and rockfish longline fisheries in BC waters, despite the mandatory use of seabird avoidance devices as a condition of licensing (in the halibut fishery). Therefore, it is likely just a matter of time before a Short-tailed Albatross is taken in BC waters. Mortality associated with oil fouling represents the greatest potential threat in this regard.