The report is part of the effort to characterize the ecosystem of the Galveston Estuary. Its purpose is to investigate the probable causes of trends in the abundance of certain species, especially recent declines, as they relate to the overall health of the ecosystem. For some species, confining the discussion to a geographic scale as small as a single estuary may give a false impression of its population. But the primary question here is that of the health of the estuarine system, not the health of a particular species. The species emphasized are those determined in an earlier study with an emphasis on ecologically and commercially important organisms: finfish and shellfish, locally breeding birds, alligators, plankton, and open bay and marsh benthos. Statistically significant declining trends were most conspicious for white shrimp, blue crab, and certain species of colonial waterbirds.

"This project has been funded in part by the United States Environmental Protection Agency under assistance agreement # CE-006550-01 to the Texas Water Commission"--T.p. verso. "August, 1993." Includes bibliographical references (p. 81-92).