COA AND CONSERVATION
Endangered Mollusks
The phylum Mollusca is
a very large and successful one. Because it has been around
for over five hundred million years, its species have had time
to exploit almost every habitat on earth; there are marine,
freshwater and terrestrial species. Mollusks can be found from
the mountain heights and tree branches to the mud of the ocean's
abyssal depths. There are creepers, burrowers, swimmers, drifters,
encrusters and species that live within starfish, crayfish,
parrotfish and freshwater fish. They are filter feeders, algae
and plant and fungus grazers, active hunters, parasites and
scavengers. They breathe air or water, live in our familiar
carbon-based ecosystem or cluster around the warm silicon-rich
waters of hydrothermal vents. Their diversity is nothing short
of miraculous.
But like most other animal groups
in today's changing world, no matter where or how they live,
the animals of the phylum Mollusca are vulnerable to the changes
man is bringing to this earth. We threaten their habitats and
food supplies, the purity of the water they breathe and, through
unregulated fisheries, the very numbers of their populations.
Some species of mollusks have become extinct because of our
activities and others teeter on the brink. Vital to their survival
is our understanding of the damage we do to the environment
we share with them and of the ways that damage affects them.
To save them we must study them, document their life histories,
their needs and weaknesses, and learn to appreciate them as
the valuable natural resources they are.
Here are some facts:
- "Up to 100 species [animals
and plants] become extinct every day. Scientists estimate
that the total number of species lost each year may climb
to 40,000 by the year 2000, a rate far exceeding any in the
last 65 million years."
- "Today, more than 200
animal species in the United States are classified as endangered
[this number includes 79 species of mollusks]. More than 1,000
animal species are endangered worldwide."
- "Little-noticed aquatic
species are in big trouble. In North America, a third of our
fish species, two-thirds of our crayfish species and nearly
three-quarters of the mussel species are in trouble."
(reprinted from
the National Wildlife Federation, Endangered Species: Facts
About Endangered Species page)
What do we mean by the term
endangered species?
An endangered species is an animal or plant that is in danger
of becoming extinct. In most cases species that are listed as
endangered WILL become extinct in the very near future unless
some positive action is taken.
How does this differ from a threatened
species? A threatened species is an animal or plant that is
likely to become endangered in the foreseeable future. This
is determined by decreasing population size and increased habitat
destruction.
Which species of mollusks
are endangered?
We don't always know. Some
rainforest species of mollusks may become endangered and then
extinct before they are ever known to science. Marine mollusks,
because of the vastness of their habitat, have scarcely been
studied. Other areas are so remote or so inhospitable or in
such political turmoil that little has been done in the way
of species surveys, let alone investigations into which species
are in jeopardy. But a lot of information is available and it
can give us a glimpse of the tip of the "extinction iceberg".
We provide you here with some
links to several lists of endangered, threatened and rare species.
Few of these lists concentrate solely on mollusks, and most
of them raise more questions than they answer, but it is important
to remember that these lists are a beginning, and that the extinction
process is not limited to any single group or area, but flows
readily across biological and geographical borders.
These lists may, or may not be
current, but we believe they do provide valuable information.
The U.S. Fish and Wildlife Service,
Division of Endangered Species, monitors and lists our U.S.
threatened and endangered plants and animals. However, not all
species that are in trouble are listed. This happens for a variety
of reasons. There are undoubtedly mollusks that are suffering
serious depletion, at least in some heavily populated or polluted
areas, but they have no spokesman, so they do not appear on
these lists.
One of the USFWS lists tallies
endangered species by region and state. Check your state to
see what needs your protection.
A second list is restricted
to just Endangered and Threatened invertebrates of the U.S.
, and it has separate sections for bivalves and snails (as well
as sections for other invertebrates). This list offers a lot
more information about many of the endangerd mollusks as well
as some further links. Then there are pictures of some species,
especially the freshwater mussels. Check it out. You'll learn
a lot.
The 1994 ICUN Red List, created
and maintained by the World Conservation Union, it is a searchable
database which you can ask for quite general or very specific
information. This list is not restricted to mollusks.
The
World Conservation Monitoring Centre
