ABSTRACT
CONTENTS Introduction ............................................................................................................................................ 381 Species Choices ..................................................................................................................................... 382
Taxonomic Group......................................................................................................................... 382 Life Stage ..................................................................................................................................... 382 Level of Organization................................................................................................................... 382 Trophic Status............................................................................................................................... 383 Estuarine Dependency.................................................................................................................. 383 Sensitivity ..................................................................................................................................... 384 Prior Database .............................................................................................................................. 384 Importance to Stakeholders.......................................................................................................... 384
Laboratory vs. Field............................................................................................................................... 384 A Case Study: A Plan and an Example to Establish a Fish Species as an Estuarine Indicator.......... 385
Method ......................................................................................................................................... 386 Results ......................................................................................................................................... 386
Conclusions ............................................................................................................................................ 390 References .............................................................................................................................................. 390
The goal of developing effective estuarine bioindicators is to determine the health of the ecosystem and causes of any detrimental changes. Adverse changes in aquatic habitats are often manifested in stress on fishes (see Adams, 1990, for an inclusive presentation). Studies on the impact of such stress are well documented in freshwater lentic and lotic environments, but are conspicuously rare for estuarine situations (Simon, 1999). It is important to note that our objective here is to use quantifiable indices of fish condition to assess the scale and direction of changes in the estuarine environment. A primary aspect of estuarine health is the response its biological components make to changes in abiotic and biotic factors of natural and anthropogenic origin. Separation of these two major causative agents poses a great problem, but the effort is crucial in assessing whether observed changes in the estuary are perceived as adverse or benign. The solution to this conundrum lies with a precise application of the scientific method across the entire spectrum of experimental control of variables and the realism of the conditions of study. This requires both field and laboratory observations and experiments, and includes experimental simulations extending from mathematical models, to highly controlled laboratory experiments, to mesocosms, to studies in the most complex but least controlled of natural circumstances. Any one level of study, no matter how elegantly conducted, will be inadequate to provide a full-scale explanation of natural events and their separation from anthropogenic influences. Some fish are ideally suited for this modern approach as they lend themselves well to multiple levels of inquiry.
