pacific islands report_NU.indd - Whale and Dolphin Conservation ...

5Cetacean Species in the Pacific Islands RegionRegular, irregular and sometimesvast migrationsThe migration of many cetacean species is cyclicaland predictable, coinciding with changes in seasonand the recurring changes in food availability. Theperiod spent between the ends of a cetacean’smigration is also important parts of their life cycle.The migration routes of many species cross regularlybetween the national jurisdiction of coastal and islandCountries and Territories. Some species regularlycross from national jurisdictions into the high seas.Other cetacean migrations are less predictable.There are movements within some of the enormous‘home ranges’ which constitute migrations in thesense that such forays might involve the animaltravelling the length and breadth of its normal homerange, comprising several thousand kilometres andsometimes entirely on the high seas. Such journeysare often undertaken with less predictability. Thesemovements can appear random, or driven by uniquecircumstances, and may not appear to be cyclic.However the subtleties and extent of such migrationsare difficult to evaluate without continuouslymonitoring individuals and the components oftheir habitats to determine the impetus for suchmovements. For many species this data is not yetavailable. Such long journeys may still constitutemigration under the working definition of CMS, eventhough the cyclical nature and predictability of thesemigrations may, at present, be unclear.Considering species and populationsMany cetacean species inhabit vast marine regions.Some species are thought to have movementsbetween populations on a regular basis, whereasother populations remain more distinct. Overlappingmigrations may occur, but specific populations mayremain isolated from each other. The conservationstatus of a migratory species means the sum of theinfluences acting on the migratory species that mayaffect its long-term distribution and abundance.For this reason the assessment of population statusis critical. There can be little doubt that thereare a number of significant pressures which actindependently and cumulatively to influence not onlythe migration of cetaceans but also their long-termpopulation distribution abundance and survival.Status and habitat of recorded andpotential Cetacean Species in the PacificIslands RegionKnowledge regarding population size, dynamicsand migration patterns of cetaceans within thePacific Islands is largely unknown with the possibleexception of humpback whales as a species (e.g.,Garrigue et al. 2002, SPWRC 2004). In this chapter,habitat descriptions are based on general reviews(i.e., Carwardine (1995) or Reeves et al. (1999, 2003)unless otherwise indicated), classifications to thelevel of subspecies have been adapted from Reeveset al. (2003), and IUCN criteria have been taken fromthe most recent Red List (IUCN 2006). Difficultiesassociated with individual species identification,sub-species differentiation, and recent nomenclaturechanges (which many records pre-date) are brieflydiscussed where appropriate. An appendix – tableprovides status and species listing, whilst habitatand identification issues are listed in the text.Descriptions of the IUCN categories are provided inthe Appendix.SUBORDER MYSTICETIFAMILY BalaenidaeEubalaena australis, Southern Right WhaleHabitat: Cold waters of temperate and subpolarSouthern hemisphere waters.Southern right whale populations are circumpolarbetween approximately 30° and 60°S withgeneralized movement from higher latitudes whereCURRENT STATE OF KNOWLEDGE OF CETACEAN THREATS, DIVERSITY, AND HABITATS IN THE PACIFIC ISLANDS REGION 65