biology > right whale biology
|
 North
Pacific Right Whale
(Eubalaena japonica)
One of the first targets of the early
pelagic whalers, the population of North Pacific right whales was significantly
reduced by 1860. Subsequent low level whaling, and an intense burst
of illegal whaling in the 1960s in Alaskan waters pushed this population
to the brink of extinction. This remains the most endangered population
of large whales in the world today.
The basic aspects of the biology and ecology
of the North Pacific right whale are poorly understood. What
we do know is based on scant information from the last years
of whaling were less than a dozen animals were killed, and
from its well studied cousin – the North Atlantic right
whale. |
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common name |
North Pacific right whale |
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scientific name |
Eubalaena japonica |
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body size |
Adults can reach up to 18 metres in length,
and may weigh as much as 100 metric tons. Females are larger
than males, and calves are around 4.5 metres in length at
birth.
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average life expectancy |
It appears from the NA population that the
life expectancy may be somewhat longer than humans, with animals
potentially living to over 100 years.
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physical
characteristics |
Right whales are distinguished by a stocky body, no dorsal
fin, and a large head about 1/3 of the body size. They are
black with occasional white patches on their ventral surface,
and may have considerable callosities around the head. They
have a broad, all black tail with a smooth trailing edge.
The blow of right whales appears V-shaped when viewed from
the front or rear.
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distribution |
Right whales were once common in temperate latitudes of all
of the world’s oceans. Today, the Antarctic population
appears to be recovering, while remnant populations persist
in the western Pacific (hundreds), eastern Pacific (tens),
and western North Atlantic (hundreds).
The warm equatorial waters naturally separate the northern
and southern populations, and also keep the North Atlantic
and North Pacific populations apart. There is thus no likelihood
of a rescue effect for the North Pacific population.
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travel speeds |
Right whales are one of the slowest whale species, typically
traveling at 1 – 2 knots (2-4 km/h).
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diet |
North Pacific right whales are low trophic level filter feeders
believed to feed almost exclusively on copepods (Calanus spp.).
A single whale can eat several metric tons of copepods a day.
They are typically characterized as skim feeders, but are
also known to feed on copepod aggregations at depth. It is
the right whales’ dependence on large, dense aggregations
of prey that determines much of their distribution, at least
during the non-breeding season.
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population sizes & trends |
The pre-exploitation abundance of North Pacific right whales
has been estimated at between 11,000 and 20,000 animals. Today
they are extremely rare in the eastern North Pacific, having
been reduced to near extinction by 19th century pelagic whaling
and illegal Soviet whaling in the 1960s. Population trends
in the North Pacific are unknown.
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typical dive times |
When traveling, right whales appear to average dives of about
6 minutes. However foraging animals have been observed to
spend as much as 15-20 minutes underwater.
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conservation status |
In Canada, Endangered since 2004 under SARA (COSEWIC)
In US, Endangered since 1970 under ESA
The population of eastern North Pacific right whales may number
in the 10s of animals making it difficult and expensive to conduct
direct observations. Acoustic tracking has significantly improved
the encounter rate, however answers to important conservation
questions (e.g., abundance, population trend, habitat use) will
be slow in coming.
page last updated March 29, 2007 |
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