North Bottlenose Whale

Scientific name: Hyperoodon ampullatus
Mi’kmaq name:

Information: A 6-9 metre long beaked whale found in deep, cold water. About 260 individuals are found in “The Gully”, a Marine Protected Area, at the edge of the Scotian shelf. Threatened by acoustic noise, chemical pollution, vessel collisions, fishing gear entanglement, marine debris, and nearby oil and gas activities.

Description

The Northern Bottlenose is a member of the beaked whale family, Ziphiidae. The whales of the Scotian Shelf population are 6 to 9 m long at maturity, about 0.7 m shorter than those in other populations. A bulbous “forehead” rises abruptly from the short beak in adult males; it is less prominent in females and young males. The Northern Bottlenose Whale is variable in colour, ranging from chocolate brown in young animals, to light brown in older animals, to yellowish brown (with whitish beaks and heads) in very old males. The small dorsal fin, about two thirds of the way down the back of the whale’s body, is triangular shaped with a pointed peak. The broad tail flukes are unnotched.

Distribution and Population

The Northern Bottlenose Whale is confined to the northern Atlantic Ocean. It can be found off the east coast of North America from Davis Strait to New York. The Scotian Shelf population is found in and around the Gully, a prominent submarine canyon on the edge of the Scotian Shelf off the southeast coast of Nova Scotia. The Gully is the southernmost area in the western North Atlantic where the Northern Bottlenose Whale is routinely found; the next closest area is 1400 km away, off northern Labrador. Based on mark-recapture methods using photo-identification records from 1988 to 1999, the Northern Bottlenose Whale Scotian Shelf population is estimated at 130 individuals. This number reflects improved methodology, and does not represent a decline in the number of whales from the estimate of 213 in 1997.

Habitat

Many of the whales in the Scotian Shelf population of the Northern Bottlenose Whale can be found in a 20 km x 8 km core area at the entrance to the Gully. The whales are never seen in water less than 800 m deep, and apparently prefer depths around 1000 m. Survey results suggest that when they are not in the Gully many of the whales can be found in the Shortland and Haldimand canyons, which lie about 50 and 100 km to the east.

Biology

Northern Bottlenose Whales in the Scotian Shelf population differ in many ways from other Northern Bottlenose Whales. The northernmost populations of the whale migrate to the southern part of their range, between New York and the Mediterranean, for the winter months, while the Scotian Shelf population appears to be nonmigratory. Whales in the Labrador population mate and give birth in April, whereas recent observations indicate that whales in the Scotian Shelf population mate and give birth in August. Genetic analysis has also confirmed that the Labrador and Scotian Shelf populations are significantly different from each other; it has been estimated that the exchange of females between the two populations is less than five per generation. Northern Bottlenose Whales in the Scotian Shelf population are typically seen in small groups. During mating and calving time there are mixed groups of two to eight females and young, with one to three males. The remainder of the year the sexes are largely separate, with males found in groups of one to five individuals and females and young in slightly larger groups of up to nine individuals. Northern Bottlenose Whales dive deeply in search of Arctic Squid, their main food. Their dives regularly exceed 1000 m, reaching the bottom of the deep canyon of the Gully, and the whales may remain there for periods of up to 70 minutes. Bottlenose whales do not usually raise their tail flukes at the beginning of a dive. Northern Bottlenose Whales live approximately 30 to 40 years, are extremely curious, and will often investigate stationary boats.

Threats

Human activities, including commercial shipping, fishing activity, and petrochemical exploration and exploitation, threaten this population. These activities result in acoustic and chemical pollution, entanglement in fishing gear, floating debris, and collisions between whales and vessels. The major east-west trans-Atlantic shipping route lies about 30 km south of the Gully core area. Oil and gas exploitation on the Scotian Shelf bordering the Gully has the potential to harm the whales directly through the noise from drilling and other activities, and pollution from spills and discarded waste and indirectly because of increased shipping traffic. One discovered oil field, the “Primrose,” lies only about 5 km from the core area of the Northern Bottlenose Whale Scotian Shelf population; exploitation of this field could cause the animals to abandon their preferred habitat. The effect of the noise from seismic surveying and drilling is unknown, but it has been suggested that bottlenose whales, because of their deep-diving behaviour, may be more vulnerable to physiological damage from underwater noise. Bottlenose Whales also produce social sounds which are of very low amplitude, and noise from shipping traffic and seismic activity might interfere with this communication.

Courtesy of Species at Risk Public Registry, Government of Canada
Website: www.sararegistry.gc.ca

Contact

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