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Biology > harbor
porpoise > fast facts
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| scientific
name |
Phocoena phocoena
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| body
size |
1.4-1.9 m, 45-60 kg
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| average
life expectancy |
8-12 years
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| vocal
behavior |
Harbour porpoise can emit a very broad frequency range (40 Hz
to at least 150 kHz) of sounds. Some are within our hearing range
(sonic) and others are above the frequency range that humans can
hear (ultrasonic)
Use slow repeated echolocation clicks for navigation and rapid
bursts of echolocation to focus in on prey or other items of interest.
Have also been reported to use whistles, which may have social
or communication significance.
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| physical
characteristics |
Are grayish- brown on their backs and sides, with white undersides.
There are often gray stripes or flecks within the white pigmentation,
especially in the throat region.
A distinctive lateral grey - brown stripe extends from the corner
of the mouth to the anterior insertion of the pectoral flipper
on both sides of the animal. The width and pigmentation of this
stripe varies among individuals, however is rarely visible on
wild, healthy animals.
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| behavior |
Harbour
porpoise surface with a gentle rolling motion and infrequently
breach or display at the surface, although when feeding in
tide lines, they will often fast-surface creating a low splash.
Unlike Dall's porpoise, harbor porpoise rarely approach vessels
that are underway, however, the harbour porpoise of southern
British Columbia have been observed to occasionally exhibit
vessel curiosity, especially when clustered in large aggregations.
During these aggregations, they have been observed to "surf" in
the vessels stern wake. |
| distribution |
The
harbour porpoise has a Northern Hemisphere, circumpolar distribution
and is found in the Pacific and Atlantic Oceans, and in the Black
Sea and Sea of Azov. This species inhabits the cold-temperate, sub-arctic
neritic waters of North America, the Russian Federation and Eurasia;
as well as some mid North Atlantic landmasses, such as the Faeroe
Islands, Greenland and Iceland. They are typically found in coastal
ocean waters, although they have been reported to swim up rivers
while pursuing prey. |
| diet |
Often overlaps with species that are commercially important
to humans.
A variety of small fish, such as herring, hake, codfishes, and
also on small squid (cephalopod). Pacific cephalopod prey
species include the market squid or opal squid, also known as
calamari.
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| foraging
behavior |
Harbour porpoise feed on prey both within the water column and
on the sea floor. They typically eat fish and squid between 10
- 25 centimeters in length. Like other odontocetes, they cannot
chew, so they must swallow their prey in whole pieces. It has
been proposed, that harbour porpoise may go for larger fish,
but will attack them from behind and bite through them at the
gills, ingesting the body without the head. Experiments at the
Harderwijk rehabilitation center for stranded harbour porpoise
in the Netherlands have shown that harbour porpoise actually
create negative pressure in their mouths, using their tongues,
to suck the fish into their mouths. This would reduce the likelihood
that a live fish could escape. They also manipulate fish to swallow
them headfirst. Some harbour porpoise have died by trying to
eat prey that is too large to swallow.
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| habitat |
Are coastal species that are typically found in relatively shallow
waters to about 150 metres. However, there are sightings of harbour
porpoise in much deeper areas. In Georgia Strait, harbour porpoise
have been observed in waters over 400 m deep.
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| reproduction |
Harbour porpoise give birth to one calf every year to every other
year after a 10 -11-month gestation period. Lactation lasts for
approximately 9 months but calves will start to consume solid
food at about 5 months of age. Calves may stay with their mothers
for up to another 9 months post-weaning. Groups of 2 –3
animals are very common in British Columbia. It is possible that
these groups are mothers with their growing calves.
Reproduction is thought to be based on sperm competition, rather
than competition between males for females. This is because the
testes of a male harbor porpoise are exceptionally large during
the reproductive season and may account for 4-6% of his body weight.
This means that a 50kg male, will have approximately 2 kg testes!
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| conservation
status |
Under Canada’s Species At Risk Act, the harbor porpoise
is classified as a species of Special Concern in both the
Atlantic and Pacific Oceans. The harbour porpoise is considered
particularly sensitive to human activities.
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Last updated 21 February 2006
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Harbor Seals Fast Facts >>>
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