Perspectives on the Chesapeake Bay, 1992

Introduction

Perspectives on Chesapeake Bay, 1992 is the third in a series of research volumes that have been published by the Chesapeake Bay Programs' Scientific and Technical Advisory Committee (STAC) since 1988. The purpose of these literature syntheses is to provide managers, scientists, legislators, and other interested people with summaries of research findings, key management issues, and other information on a range of Chesapeake Bay oriented topics-all presented at a technical level comprehensible to the generalist. Each volume, therefore, is intended to make a useful contribution to a better understanding and the improved management of the Bay's ecosystem-and ultimately to the restoration and sustained well-being of what is the nation's largest estuary.

This volume consists of for papers, each of which focuses on a specific research topic:

• "Ecological Functions and Values of Nontidal Wetlands, " by Carl Hershner, reviews our current understanding of the functions of nontidal wetlands, assesses the problems of assigning values to wetland functions, and surveys the use of these functions and values in management programs of the mid-Atlantic states. Although the author discusses nontidal wetlands in general, he makes it clear that the finding and implications of numerous wetlands research studies are directly applicable to all wetlands in the Bay.

The focus on nontidal wetlands it timely and relevant. Even thought they account for over two-thirds of the Bay area's wetland acreage, research generally has been limited to specific wetland types and functions,; it has not yet led to an equal understanding of all potential wetland functions. Among the functions described in the paper are groundwater recharge and discharge, flood storage and desynchronization, shoreline anchoring and the dissipation of erosive forces, sediment trapping, nutrient retention and removal, food chain support, provision of habitat for fisheries and wildlife, and recreational opportunities.

Currently, wetlands managers are faced with a dilemma of competing interests: the preservation of these irreplaceable resources versus the demand for development of natural areas by our rapidly expanding population. Giving the "fundamental incompatibility" of these two interest, the author declares, it is essential to a have "a generally accepted method of determining the value of one wetland with that of another." However, as he concludes, such a method is not yet available, although considerable progress could be made in the Chesapeake Bay region "if the efforts of multiple research and funding agencies could be ... [incorporated into a] well-planned research strategy."

• "Groundwater Discharge in Coastal Systems: Implications for Chesapeake Bay, " by William G. Reay and George M. Simmons, Jr., examines the role of groundwater as both a source and transport mechanism of nutrients and other contaminants. As the authors demonstrate, that role is a significant one in many coastal regions, but it needs to be better understood in the Chesapeake Bay watershed, where most research to date has concentrated on the contributions of point-source contaminants and non-point source surface runoff. Furthermore, the studies reviewed by the authors mostly concentrate on dissolved inorganic nitrogen; however, there are other groundwater contaminants, such as synthetic toxic compounds and pesticides, that also should be studied closely.

Drawing from their analysis of the leading studies, the authors conclude their paper with several broad research recommendations that are designed to provide a more complete scientific understanding of the Bay region's groundwater discharge processes and groundwater/wetland interactions, a more comprehensive system of groundwater monitoring, and the development of so called best management practices that take into account groundwater contamination and the transport of such groundwater-borne pollutants to aquatic systems.

• "Low-Level Effects of Toxic Chemicals on Chesapeake Bay Organisms," by David A. Wright, Jacqueline D. Savitz, and S. Ian Hartwell, focuses on the low-level effects that toxic substances have on certain Bay species. These effects are generally less obvious and more pervasive than that lethal responses measured in the laboratory and observed in the Bay waters. The authors describe the principal toxological approaches used by researchers and summarize the findings of numerous field and laboratory studies. They conclude that, although there is strong evidence that toxic substances do have adverse effects on the Bay' s biota (tumors in fish have been correlated with exposure to toxicants, for example), more research is needed to ascertain the precise linkages that may or may not exist between low-level exposures and various effects, such as the decline of a fish stock. Furthermore, most of the studies to date have concentrated on the Elizabeth River, which is most heavily polluted portion of the Bay system, and those studies have been useful in establishing a reliable connection between contaminant and effect. Accordingly, the authors call for a systematic approach to a Baywide determination of toxicity.
• "Fisheries Assessment and Management Synthesis: Lessons for Chesapeake Bay," by William A. Richkus, Steven J. Nelson, and Herbert M. Austin, describes the basic approaches that are used for stock assessment of the fish and shellfish stocks of the Chesapeake Bay system. The authors summarize the principal methods of stock assessment and fisheries management that have been-and are being-applied to Bay fisheries, with particular emphasis on data collection and the use of models. They then present case studies of three critical species: (1) the striped bass, a Bay-spawning pelagic predator that has suffered a serious stock decline during the past two decades but holds promise of being restored through the current use of a vigorous and effective management strategy; (2) the blue crab, a benthic scavenger that has been the basis of the Bay region's most valuable fishery for almost a decade but now faces the possibility of undergoing a serious stock collapse cause by overfishing; and (3) the Easter oyster, a native shellfish species that was long the basis of the Bay's leading fishery, but, since the 1960s, has declined to the point where it is questionable that the fishery can continue.

Both in the body of the paper and in the three case studies, the authors summarize the findings of a variety of studies (including some that look at striped bass stocks elsewhere in the United States, for comparative purposes), and they also summarize the status of stock assessment efforts and the pros and cons of the various models that have been developed and applied to Bay species. Based on their review, the authors conclude that the data required for effective stock management is still not available, which seriously hampers the use of models and other analysis and management tools. Accordingly, they state, "current fisheries management priorities for the Bay must continue to be focused on recruitment-related issues."