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 Endangered
Marine Mammals |
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 An
endangered animal or plant is a species that is considered in
immediate danger of becoming extinct. Its population is very
small and it needs active protection to survive. In the United
States, hunting of endangered animals is not allowed. Neither
is importation of their meat, fur, tusks, blubber, or other
products.
Extinction has happened throughout history, but in modern times
the rate has increased dramatically. There is a link between
the increase in the extinction rate and the growth in human
population. The worldwide human population was 1 billion in
1600, 1.5 billion 100 years ago, and is over 6 billion today.
At the same time, the species extinction rate has increased
to one species a day. If this continues, it will cause a dramatic
drop in the diversity of life on our planet, which will most
certainly have serious effects.
Increasingly, people crowd out places for wild plants and animals
to live. Some animals and plants can survive in only one specific
type of habitat, and when their habitat disappears, so do they.
Some areas have become too polluted and unhealthy for animals
and plants to survive. Recreational activities also interfere
with wildlife. For marine mammals, there is the special problem
of accidental entanglement in fishing nets and collisions with
boats.
 Marine
mammals that are on the endangered or threatened species list
include southern
sea otters, manatees,
Guadalupe
fur seals, monk seals, humpback,
blue, fin,
sei, right and bowhead whales. The western Pacific population
of the Steller
sea lion was added to the endangered list in 1997 in response
to an 80% drop in its population over the last 30 years. The
eastern population is still listed as threatened.
Most of the large whale populations initially became low due
to hunting. For instance, blue
whales, the largest animals on earth, once numbered 200,000.
Today the worldwide population is estimated to be 10,000. Other
whales, such as the humpback,
right, and bowhead are still endangered, despite being protected.
 In
contrast, the gray
whale population has made a comeback and has been taken
off the endangered species list. The return of the gray whale
might be explained by some habits they have that are not shared
by the other baleen whales. Virtually all gray whales migrate
to the same place every year, therefore, they can more easily
find a mate. Additionally, most females produce one calf every
other year, therefore, they have a relatively high birth rate.
Many marine mammal scientists are now becoming concerned with
the drop in numbers of dolphins and porpoises. River dolphins
that live in Asia and the Amazon are disappearing due to dam
building and habitat destruction. Another concern is the number
of dolphins
dying in the tuna fisheries of the eastern tropical Pacific.
Historically, yellowfin tuna has been caught by encircling the
dolphins that swim above the tuna with purse seine nets. Over
100,000 dolphins per year died in the 1970s and early 1980s
after being caught in tuna nets, and several species of dolphins
in the eastern tropical Pacific are now considered depleted
under the Marine Mammal Protection Act. Efforts of environmental
organizations and consumers led to "dolphin-safe"
labeling of canned tuna, and a 98% reduction in dolphin mortality
since 1990. However, recent changes in US and international
laws have reopened this complex issue, and the outcome is in
doubt. Fortunately, the major companies have all promised to
sell only tuna that is caught without encircling dolphins. For
more information on the tun-dolphin issue, go to the Earth
Island Institute home page or the National Marine Fisheries
Service Dolphin
Interactions with the Eastern Tropical Pacific Tuna Purse Seine
Fishery page.
 Another
marine mammal, the southern
sea otter, was driven to the verge of extinction from being
hunted for its fur. The California sea otter population, once
over 250,000, today numbers around 1,925. Although protected,
sea otters remain very vulnerable to oil spills; oil soils their
fur, destroying its insulating capabilities, which leads to
hypothermia. In addition, new diseases and parasites are infecting
sea otters and causing a decline in their populations.
 Many
marine mammals in the seal family also suffered a similar fate
from hunting. The Guadalupe
fur seal once ranged into California, and now its population
is reduced to 7,400, centered around Guadalupe Island in Mexico.
Northern
elephant seals were once hunted for their oil. Although
they were once endangered with fewer than 100 individuals in
the late 1800s, their population now has recovered to over 150,000.
In recent years, many seal and sea lion species in Alaska have
declined including populations of northern
fur seals, harbor
seals, and Steller
sea lions. It is believed that one of the major reasons
for their decline is accidental catch in fishing operations
and competition for food with commercial fisheries.
Other marine mammals, such as the Steller sea cow, Caribbean
monk seal, and certain whale stocks, have actually become extinct
in historic times. The Steller sea cow was discovered in 1741
by the Vitus Bering expedition. Due to over hunting for its
meat, the sea cow vanished in 1768, within 27 years of its discovery.
Unfortunately, a relative of the Steller sea cow, the West Indian
Manatee, is now in severe danger of extinction. In 1989, the
estimated manatee
population in Florida was 1,200. The following year over 140
manatees died. Human causes were responsible for 75% of these
deaths, and the single biggest cause of deaths was attributed
to being hit by boats. Manatees are very slow movers and sometimes
sleep near the surface of the water. Motor boat encounters often
result in severe injuries and broken bones. Manatee reserves
have been set up, but death rates are still high, probably due
the popularity of motor boating and growth in Florida population.
Manatees give birth only every three years or so. Unless drastic
measures are taken, manatees could become extinct.
You can help protect endangered marine mammals. You can 1) support
non-profit organizations like The Marine Mammal Center, working
to rescue and protect marine mammal species; 2) support legislation
that helps keep the ocean clean and protects habitat; and 3)
make wise choices as consumers. You can use products that are
biodegradable and less harmful to the environment. You can recycle
bottles, aluminum, paper, and plastics, which helps to protect
habitat. You can choose recreational activities that do not
disturb habitat or wildlife. You can avoid buying products that
endanger wildlife and plants such as tuna (non-dolphin-safe),
ivory, wild animal fur and feathers, and tropical woods. We
also need to pressure government to come up with effective recovery
programs for endangered species. Write to your legislators to
voice your support. Together, we can help protect the rich variety
of life on earth.
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