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