Full document / COSOC-W-86-002 - the National Sea Grant Library

production Is uncertain. Thus, the Importance and ecological
efficiencies of food chain pathways remain unresolved. Food chains In
estuarine ecosystems are connected quantitatively and qualitatively. We
must understand the relationship between quantity of blomass at one
producer level and the quantity and quality of blomass at the next
level. The concept of the trophic structure In an estuarine ecosystem
1s more of a food web than a food chain. Moreover, the food web trophic
structure found In the estuary if generally abbreviated compared to the
longer food chain found In the ocean and the open water of the Great
Lakes. The problem of understanding the fundamental aspects of this
Issue is difficult because of the likelihood that a change in one
trophic level impacts other portions of the ecosystem by altering the
directions or size of energy flow from one component to another.
5. Habitat requirements for fisheries production
Estuaries act as nurseries for Important commercial and recreational
fish and shellfish. But some estuaries produce more ftsh than others.
Understanding the role of estuarine habitat and quantitative differences
In fisheries production will provide the key to more effective fisheries
management. To find out what makes one estuary more productive than
another, scientists need to address questions about habitat selection,
species migration, species residence time, food quality and the effects
of environmental variations on survival, growth and movement of fish and
shellfish.
National Estuarine Management Issues
Recently efforts have been made to identify the most relevant coastal
management Issues facing the United States. These efforts have Included
researchers, managers and public interest groups through various public
meetings, management conferences and symposia throughout the country.
These efforts have culminated In the second national estuarine symposium
held in Baton Rouge, Louisiana during November 1985. At this symposium,
prominent U.S. estuarine experts concluded that a better understanding
of the following seven issues represented our most critical national
estuarine management needs:
1. The relationships between physical and chemical variables and the
productivity of estuartne ecoystems;
2. The effects of foreign substances, especially pathogenic materials
and toxic chemicals, on the chemical and biochemical processes In
the estuartne environment;
3. The impact of man's activities on the fundamental functioning of
estuarine ecosystems;
4. The appropriate measures for ameliorating undesirable effects and
reclaiming damaged estuarine ecosystems;
5. The means to Increase harvest of fisheries products;
6. Methodologies to Improve the economic return of land around the
estuaries by resolving the conflict between land use changes and
estuarine productivity; and
769