Grey whale (Eschrichtius robustus) recovery strategy: chapter 1

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Executive summary

The grey whale is a medium to large-sized mysticete (baleen) whale, with a maximum length of around 15 m.  Its skin colour ranges from dark to light grey with various degrees of mottling.  Because of a variety of distinctive characteristics, the species is placed in the monotypic family Eschrichtiidae, separate from all other whales.

Historically found in the North Atlantic and North Pacific, the species is currently extant only in the North Pacific where there are two populations.  Distribution in the western North Atlantic, including Atlantic Canada, is inferred from the distribution of subfossil remains, historical observations of whaling captains, and distribution and migratory behaviour of the extant eastern Pacific population.  Subfossil remains and whaling observations are known from New England to southern Florida.  Atlantic grey whales may have visited Canadian waters including the Scotian Shelf, Gulf of St. Lawrence, Grand Banks, and possibly as far north as Hudson Bay. 

Grey whales are thought to have become extirpated from the western North Atlantic before the end of the 1800s, and specialists have inferred that the population was extirpated due to harvesting.

There is no information on the biological needs or the critical habitat of the western North Atlantic population of grey whales, which would have included individuals occurring in Canada.  Based on information from the eastern North Pacific population, northwest Atlantic grey whales would have required productive feeding grounds in northern waters, shallow warm protected coastal lagoons for breeding and calving in southern subtropical waters, and a migratory corridor, probably within a few kilometers of the shoreline, connecting these areas.  The primary historical threat was harvesting, but harvesting large whales is no longer permitted in Canada except for very limited subsistence needs of northern Aboriginal people.   Current potential threats to grey whales include entanglement in fishing gear, ship strikes, and degradation of coastal habitats.   

Recovery of this population is determined to be not feasible.  Although individuals exist in the eastern North Pacific to support reintroduction, a large number (more than 100) would be required to re-establish a viable population, and the transport of large whales on this scale has not been shown to be feasible.  Even if reintroduction on this scale were feasible, it is highly doubtful that the long migratory pattern and complex ecological relationships essential to the life cycle of this species could be re-established.