Recovery Strategy for Blue, Fin, and Sei Whales in Pacific Canadian Waters [Final]
- 1 Introduction
- 2 Blue Whale Background
- 3 Fin Whale Background
- 4 Sei Whale Background
- 5 Threats
- 6 Critical Habitat
- 7 Actions Completed or Underway
- 8 Knowledge Gaps
- 9 Recovery
- 10 Evaluation
- 11 Statement of when the Action Plan will be Completed
- 12 References Cited
- 13 Glossary of Terms
- Appendix I
6 Critical Habitat
The SARA defines critical habitat as the “habitat necessary for the survival and recovery of a listed wildlife species and that is identified as the species’ critical habitat in the recovery strategy or in an action plan for the species.” Critical habitat for balaenopterid whales is likely to include spaces important for feeding, socializing, migration, and possibly other activities.
Marine habitat for baleen whales in temperate waters is most often defined as foraging habitat. This is because baleen whales are generally believed to frequent temperate waters during summer to take advantage of increased seasonal productivity. Additionally, behavioural data on these species is relatively difficult to collect, and feeding is the most observable behaviour. Feeding habitat is also the most straightforward to define, given the available oceanographic and biological data. While research efforts will initially focus on identifying feeding areas, the determination of other habitats necessary for essential life processes should not be ignored.
The distribution of blue, fin, and sei whales is believed to be somewhat sympatric. However, the lack of contemporary sei and blue whale sightings in Pacific Canadian waters makes critical habitat designation difficult at this stage of the recovery planning process.
Gregr and Trites (2001) proposed that oceanographic conditions off the north end of Vancouver Island create suitable conditions for the entrainment of phytoplankton and zooplankton. These conditions include the transport of primary production from areas of upwelling further south, the wash-out of zooplankton from the continental shelf, and the confluence of major currents creating entrainment features such as fronts and eddies. They proposed that the region (Figures 1 and 4) represented a ‘multi-species critical habitat’ area for a suite of large whale species. The importance of the region has yet to be investigated, and does not represent critical habitat in the SARA context. Nevertheless, critical habitat for these species may be largely ephemeral (e.g., fronts and eddies), structured by oceanographic conditions and their interactions with each other, and with permanent physical features (e.g., shelf-breaks and canyons).
6.1 Schedule of studies to identify critical habitat
Further research is needed before critical habitat in Pacific Canadian waters for balaenopterid whales can be identified. SARA allows for a schedule of studies to be developed to identify critical habitat where available information is inadequate (See Section 9.4.1).
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