habitat_narrative
Marine
Little is known about the key behavioural and ecological characteristics of beaked whales. Typically, these species occur in deep, offshore waters, and are considered to have long, deep-diving capabilities. Their occurrence is generally associated with topographic features, including slopes, escarpments, canyons and oceanic islands (Macleod et al. 2006). The stomach contents of stranded beaked whales suggest that their primary food source includes deep-water, mesopelagic cephalopods, although MacLeod et al. (2003) found that benthic fish and crustaceans also constitute important prey items for these species. Ziphius and Hyperoodon spp. prey upon significantly larger species, compared to Mesoplodon spp. (MacLeod et al. 2003).Mesoplodon species occur commonly in deep-waters and along continental slopes, where prey availability may be enhanced by the interactions between ocean currents and topography (MacLeod & Zuur 2005). Beaked whales are believed to be suction feeders (Heyning & Mead 1996), feeding predominantly on squid and deep-water fish. Mesoplodon densirostris is no exception. Sekiguchi et al. (1992) and Ross (1984) reported stomach contents containing the remains of Buttersnoek (Lepidopus caudatus) and lanternfish (Lampanyctus spp.). Off Hawaii, schools of between three and seven Blainvilleâs Beaked Whales were observed by Shallenberger (1981). Having documented groups of up to six individuals, Gambell et al. (1975) suggested that M. grayi form small schools. Mesoplodon grayi calves may be born in spring and summer, at lengths of approximately 2.1 m (Baker 1983). Sekiguchi et al. (1996) reported that the diet of M. layardii consisted primarily of squid in South African and New Zealand waters, with small numbers of fish and crustaceans. Stable isotope analyses revealed that M. mirus feed at a similar trophic level to other species of this genus, but may feed on smaller prey than H. ampullatus (Northern Bottlenose Whale), and at a lower trophic level than that of Z. cavirostris (MacLeod 2005).
Ecosystem and cultural services: Marine mammals integrate and reflect ecological variation across large spatial and long temporal scales, and therefore they are prime sentinels of marine ecosystem change; migratory whales may be used to investigate broad-scale shifts in ecosystems (Moore 2008).
