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As of 2004, this project is no longer current. Please see the Research Programs page for a list of current research projects.
Complexity and Stressors in Estuarine Systems (COASTES): The Importance of Understanding Ecological Complexity to Predicting Effects of Multiple Stressors on Coastal Systems
Complexity and Stressors in Estuarine Systems COASTES is a multidisciplinary program designed to improve the understanding of the effects of multiple stressors in coastal systems and the role that the complexity of natural systems plays in influencing responses to anthropogenic stress. It focuses on the Patuxent River as a model ecosystem. The Academy of Natural Sciences Estuarine Research Center (ANSERC) is the lead institution for COASTES. Research Areas focus on watershed studies, water quality, estuarine ecology, ecological models, fisheries models, and economic valuation.
Our principal objective is the development and implementation of spatially explicit fisheries models to characterize the pelagic fish community of the Patuxent River estuary.
Models:
- Evaluate growth rates and survival probabilities of larval fishes in an oxygen-structured habitat with an individual based bioenergetics / predator-prey model
- Evaluate spatial patterns of planktivore abundance and consumption rates as well as piscivore growth rates
- Assess effects of habitat structure and trophic complexity on fish growth and consumption using spatially explicit models
This project ended in 2002
2002 Accomplishments
A manuscript generated from this project, "Effect of Nutrient Loading on Atlantic Menhaden (Brevoortia tyrannus) Growth Rate Potential in the Patuxent River" by Stephen Brandt and Doran Mason was accepted by Estuaries and will be in print in a special issue sometime in 2003. The COASTES program was completed at the end of 2002.
2001 Accomplishments
We continued work on a manuscript predicting the effects of changes in water quality on fish growth and consumption in the Patuxent River. A water quality model developed by scientists at the University of Virginia, together with bioenergetics models of menhaden and anchovy and field data from the COASTES project, was used to create a predictive model. Initial simulations have been run, and we are beginning to examine the spatial and temporal changes in bay anchovy and Atlantic menhaden growth and consumption in response to changes in nutrient loadings and dissolved oxygen concentrations.
2000 Accomplishments
Having completed field work during FY99, efforts in FY2000 focused on increasing collaboration with other COASTES researchers and preparing data for sharing and analysis. Manuscript ideas were also developed and we began work on a paper addressing the effects of changes in water quality on fish growth and consumption in the Patuxent River.
1999 Accomplishments
A low dissolved oxygen submodel was integrated into the fisheries models.
During 1999, we collected data on environmental conditions and prey availability that will be used in analyses of striped bass habitat quality. Data include acoustic estimates of fish density, size, and spatial distribution along three cross-channel transects during June, July, and August 1999. Acoustic data was collected both day and night. Water temperature, salinity, and dissolved oxygen were monitored simultaneously in order to relate spatial fish distribution to environmental characteristics.
In June 1999, oxygen profiles showed little variation with depth and did not indicate large volumes of hypoxic water. Fish were generally clumped in near-surface bands during the day but spread throughout the water column at night.
During July 1999, sharp oxyclines were observed at both St. Leonard Creek and Broome's Island. Oxygen concentrations near the surface were 7-8 mg/L but declined to near 2 mg/L at depths > 12m. During the day, approximately half of the pelagic fish at both sites inhabited water with oxygen concentrations > 4 mg/L. During the night, the percentage of fish inhabiting water with oxygen concentrations > 4 mg/L increased to 87% for St. Leonard Creek and 79% for Broome's Island.
During August 1999, dissolved oxygen concentrations showed less variation with depth than during July. Dissolved oxygen concentrations ranged as low as 3.5 mg/L but concentrations exceeded 4 mg/L over most of the transect volumes (range 3.5 to 7.0 mg/L). Fish were generally dispersed throughout the water column; however, daytime data at St. Leonard Creek showed that pelagic fish were entirely contained within a deep layer of poorly oxygenated water (approx. 3.5 mg/L).
Fig. 1 Fish Density and Oxygen Concentration, St. Leonard Creek, Night
Fig. 2 Fish Density and Oxygen Concentration-Diel Comparison, St. Leonard Creek, August
Fig. 3 Fish Density and Oxygen Concentration, St. Leonard Creek, July 1999.
Fig. 4 Fish Density and Oxygen Concentration, Broome's Island, July 1999.
Fisheries models and water quality models were linked.
Integrating models of fish consumption, growth and production with water quality models continues to be a capstone goal. While work on the nutrient-plankton loop continues, we standardized our spatially-explicit fish bioenergetics models into a common format. We then developed a menu-driven software package (GRP Mapmaker v.28) that allows users to generate spatially-explicit estimates of fish growth or consumption for a variety of estuarine fish species. The raster-based format of the spatially-explicit fishery models provides a means to incorporate spatially-indexed output from a variety of hydrodynamics or water quality models.
Last updated: 2004-04-23 mbl