This field guide to freshwater mussels is the fifth contribution to a series that has been published at very irregular intervals. The first in the series of Illinois Natural History Survey manuals was published in 1936, and the fourth was issued nearly three and a half decades ago. Previous volumes covered wildflowers, snails, shrubs, and mammals.
Freshwater mussels are an interesting group of animals that are not particularly well known by the public even though most people exhibit an innate curiosity about them. Interest seems to have waxed and waned in concert with the worth of their shells in the commercial marketplace. Today the commercial exploitation of mussels, particularly in the Mississippi and Ohio river drainages, is focused on shells to be used in the Japanese cultured pearl industry. A nascent cultured pearl industry is only beginning in this country. Much of the current public interest in mussels has been stimulated by the recently introduced zebra mussel and the economic havoc it has created in some parts of its new and rapidly expanding range in North America.
Professional biologists and informed amateurs alike have recognized that freshwater mussels are particularly sensitive to anthropogenic changes in our waterways. Thus, these mussels can be used to judge stream quality or the degree of degradation. It is especially meaningful to follow changes in mussel populations over time. Because our predecessors assembled systematic collections that have been carefully maintained and because of the extensive efforts of the authors and others to reexamine watersheds and relocate previously known localities for some species, we have a better understanding of trends regarding species distribution and populations. This knowledge offers little encouragement or cause for contentment, however, because more than half of the mussel species of the Midwest are threatened or endangered. No other major group of midwestern animals is so imperiled.
Identification is usually the essential first step to unlocking information about a species. For this reason, this field guide includes color photographs and maps to assist the user in identifying mussels with a minimum of effort and specialized knowledge. I believe the user will find this approach a utilitarian one that will lead to new knowledge of, and appreciation for, this important group of organisms.
Lorin I. Nevling
Created 6/9/95 Last Modified 1/10/2002 cam