Sei whale (Balaenoptera borealis) COSEWIC assessment and status report: chapter 10

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Existing Protection or other Status

As with all the large baleen whales, the sei whale is considered at risk worldwide. The severity of historic over-exploitation and the lack of contemporary data suggest a cautious approach to determining the status of this species. The sei whale is listed as “Endangered” by the IUCN on the basis of historic exploitation. CITES lists the species under Appendix 1, the category that includes species threatened with extinction. The IWC has classified both the North Pacific and the Nova Scotia stocks as “Protected”. This designation recognizes stocks that are at less than 40% of their maximum sustainable yield levels, and therefore prohibits commercial whaling.

Both the eastern North Pacific and the Nova Scotia stocks have been listed as endangered under the United States Endangered Species Act (ESA) since 1973. The lack of information on population trends and human-caused mortality is the basis on which it remains listed (Waring et al. 2001). The US recovery plan for fin and sei whales is awaiting legal clearance (Waring et al. 2001).

In Canada, the existing Fisheries Act and Marine Mammal Regulations prohibits disturbance of marine mammals except for purposes of hunting, for which a permit is required. This has been broadly interpreted as a prohibition on harassment and has evolved into a series of whale watching guidelines. There has been no hunting of sei whales in Canada for over 25 years and there is no indication that whaling on sei whales in Canadian waters will resume in the future.

The Oceans Act appears to be the legislation under which Fisheries and Oceans Canada will work to establish Marine Protected Areas (Hooker et al. 1999), while the Species at Risk Act includes provisions to protect habitat and develop recovery strategies for endangered species.

Currently, none of the species’ range or territory is protected on either of Canada’s coasts. However, the marine portion of Haida Gwaii (Pacific coast) may eventually protect some peripheral habitat, and the designation of the Gully (Atlantic coast) as a marine protected area may also afford the species a small degree of habitat protection. However, the pelagic, long-ranging nature of this species, and the difficulties associated with protecting extensive pelagic areas make protecting sei whale habitat difficult.

As with all large whale species, much of our existing knowledge is based on data collected during the twilight of commercial whaling (1948 – 1984). The difficulties associated with corroborating and extending this knowledge using surface observations is difficult and expensive. Work has necessarily involved less intrusive techniques, which focus more on the species’ ecology (habitat use, migration, association patterns) than on the life history characteristics (mortality and reproduction parameters) necessary to refine population models. Line transect surveys are now conducted on a regular basis in the United States by NMFS for all large whale species.