Shannon Gowans

Social organization in northern bottlenose whales, Hyperoodon ampullatus: not driven by deep-water foraging?

It is postulated that deep-water foraging in sperm whales, Physeter macrocephalus, has led to communal care of young and long-term female bonds. By studying the social organization of a second, unrelated, deep-diving species, the northern bottlenose whale, we investigated the role that deep diving may play in the evolution of cetacean sociality. Northern bottlenose whales in a deep-water canyon, the Gully off Nova Scotia, Canada, form small groups (XSD=3.041.86). Associations within age/sex classes (female/immature, subadult male and mature male) were significantly higher than associations between different classes. Females and immature bottlenose whales formed a loose network of associations, showing no preferential associations with particular individuals or those from specific age/sex classes nor any long-term bonds. Mature and subadult males had stronger associations with individuals in their own class, and associations between some males lasted for several years, although males also formed many short-term associations. Overall the social organization of northern bottlenose whales in the Gully appears to resemble that of some bottlenose dolphins, Tursiops truncatus, living in shallow, enclosed bays. Thus deep-water foraging does not appear to necessarily lead to the evolution of long-term bonds between females.  2001 The Association for the Study of Animal Behaviour

Ecosystem consideration in conservation planning: energy demand of foraging bottlenose whales (Hyperoodon ampullatus) in a marine protected area

The Gully, a submarine canyon off eastern Canada, was nominated as a pilot Marine Protected Area (MPA) in 1998, largely to safeguard the vulnerable population of northern bottlenose whales (Hyperoodon ampullatus) found there. The boundaries and ultimate management regime for the MPA for this area remain under review. We have estimated the energy consumption of bottlenose whales in the Gully based on the number of whales present at any time, their trophic level, the food requirements of each whale, and the rates of energy transfer between trophic levels. These calculations suggest that there must be a substantial spatial subsidy in the underlying foodweb of the submarine canyon to support the bottlenose whales using the Gully. A substantial area beyond the distribution of bottlenose whales in the area will therefore require protection. Conservation priorities to protect such subsidies will primarily involve additional protection at the level of the sea floor. Spatial subsidies are probably common in the marine environment, urging careful ecological analysis in the establishment of marine reserves and suggesting that conservation priorities need to take into account key ecological linkages and processes that are vital for sustaining species and habitats of concern.