How many young does a whale give birth to at one time?
Most of the larger whales have a very low reproductive rate: females only have a single calf every 2-4 years. With very
small populations, this low rate of reproduction means that it may takes decades for some species to recover to their former
population levels. Even under the best conditions, it will take over a hundred years for the right whale to recover.
For some species of whales, the calves are born during the part of the annual cycle when the animals are in warmer waters,
and the adults are not feeding. Unlike dolphins and porpoises, a calf spends a relatively short period of time with its mother.
Calves usually become independent within a single year. During that time, a calf gains weight very rapidly. Whale milk is
very rich, and a blue whale calf may gain almost 200 pounds per day.
What are the main threats to whales these days?
Although commercial whaling currently does not present a threat to the survival of the baleen whales, loss of habitat and
other human activities may make recovery more difficult. Collisions with vessels, oil spills and other changes in water
quality, coastal development, and increasing noise created from the use of oceanic resources may all affect the whales.
Fisheries may affect whales in two ways. First, whales may become entangled in fishing gear. As an example, each year
several humpback whales are entangled in fishing gear along the east coast of the United States and Canada. Second, fisheries
may compete with whales for food, such as herring.
Increased noise or boat traffic may cause whales to alter their behavior. There is evidence that humpback whales in Hawaii
may have changed their use of near-shore waters where calves are raised by their mothers because of increasing human
activity. Migrating bowhead whales may move further offshore to avoid human-caused noise.
Although we do not have a full understanding of the possible impacts, pollution could also affect whales. Many contaminants
are stored in a whale's blubber for long periods of time. Pollutant loads are usually lower in baleen whales than in dolphins
and porpoises. Deterioration of the environment could possibly affect the whales in another way: if pollution and other
factors reduce the number of fish and crustaceans, the food available to the whales could also be reduced.
What are Pinnipeds?
Seals, Sea lions and Walrus are currently placed in a
Sub-order, the Pinnipedia, of the Order Carnivora
which also includes the bears, dogs, racoons, weasles
(including otters), hyaenas cats, and mongooses.
There have many recent studies on the genetic and
fossil history of these groups and their place in the
scheme of mammalian classifcation may well change
in the near future.
Three families of living pinnipeds are recognized,
the Phocidae (hair seals or true seals), the Otaridae
(fur seals and sea lions) and the Odobenidae (walrus).
The term pinnipedia translates from Latin as "fin
foot". All of these animals must come ashore to
breed, give birth and nurse their young, though some
species are at sea for several months at a time while
others return to the shore every day.
How many Pinnipeds are on the Endangered Species List?
There are currently four species of pinnipeds in the U.S. on the endangered species list. These include the Caribbean monk
seal, the Guadalupe fur seal, the Hawaiian monk seal and the Steller sea lion. The Caribbean monk seal and the Hawaiian
mink seal are listed as endangered, while the Guadalupe fur seal and Steller sea lion are currently listed as threatened.
Commercial hunting of seals in the 18th and 19th century, and in the early years of this century played a large role in
pinniped population declines. Other factors involved have been coastal development and competition with man for prey
Are Hawaiian monk seals coming back?
The Hawaiian monk seal was listed as endangered
throughout its range on November 23, 1976. Counts
have been made at the atolls, islands and reefs
where they haul out in the northwest Hawaiian
Islands since the late 1950s. By 1982, the
population had declined to half of its 1957-1958
level. Since the mid-1980's, beach counts have
declined at five percent per year. NMFS estimates
that currently there are approximately 1400
animals. The number of births declined
significantly at all five major breeding locations in
1990, followed by some recovery in subsequent
years. However, the number of births has not
reached the level observed in the mid-to-late
1980's, and is not expected to in the near future because of the high losses of immature seals at French Frigate Shoals and
mobbed seals at Laysan and Lisianski Islands.
How many Caribbean monk seals are left?
The Caribbean monk seal was listed as endangered throughout its
range on April 10, 1979. The last reliable sighting of a Caribbean monk seal occurred in
1952. None were seen in aerial surveys in 1973, and no confirmed sightings have been
reported since then. Many scientists believe that the species has been extinct since the
early 1950s. No recovery effort is being made for this species.
How are Steller Sea Lions doing?
The Steller or northern sea lion was listed as threatened
throughout its range on December 4, 1990. Steller sea lion population west of 144 degrees wes
t longitude was declared endangered as of June 1997. The centers of abundance and
distribution are the Gulf of Alaska and Aleutian Islands, respectively.
Rookeries (breeding colonies) are found from the central Kuril Islands to
Ano Nuevo Island, California; most large rookeries are in the Gulf of
Alaska and Aleutian Islands. More than 50 Steller sea lion rookeries and a
greater number of haulout sites have been identified. Species abundance
estimates during the late 1970s ranged from 248,000 to 300,000 adult and
juvenile animals. However, counts at rookeries and haulout sites
throughout most of Alaska and the USSR in 1989, plus estimates from
surveys conducted in recent years at locations not counted in 1989,
provide a range-wide Steller sea lion population estimate of about
116,000. In 1994, an estimated 67,100 occurred in U.S. waters.
All Artwork on this page is by Katherine Zecca of the Alaska Fisheries