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Progress and Plans for the Incorporation of Oysters and Menhaden in the Water Quality Model. Oysters. At present, a uniform mortality rate is employed, which represents baywide biomass
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Progress and Plans for the Incorporation of Oysters and Menhaden in the Water Quality Model
Oysters • At present, a uniform mortality rate is employed, which represents baywide biomass • Representation of local biomass requires spatially and temporally varying mortality to represent harvest and disease • Will be incorporated in 2008
Basic Issues • How to process spatially and temporally detailed ICM information for use with Ecopath? • What are the commonalities between the two models? • How to interface?
Preliminary Investigation of Increased Predation by Menhaden • 2002 ICM kinetics installed on 1992 4,000-cell grid • Ecopath model constructed by Jim Hagy • Proof of Concept Stage
The ICM Predation Term Simulate more menhaden by increasing Phtl by 20% !!!!!
Effects of Increased Predation in Ecopath on Organic Carbon Pools
Ecopath Base Ecopath with 20% Increase in Menhaden
Proposed Approach • Substitute ICM primary producers and rates into Hagy’s Ecopath model. Adjust as necessary. • Substitute ICM primary producers and rates with 20% increase in predation into above. Adjust as necessary. • Examine differences
Effects of Increased Predation on Organic Carbon Pools Common to ICM and Ecopath Mid-Bay
Conclusions du Jour • Ecopath alone is not suited for this investigation. • Requires input of algal biomass, growth rate • Does not incorporate effects such as enhanced nutrient recycling • We have explored a way in which ICM and Ecopath can be used together. ICM for primary producers, Ecopath to carry effects to higher trophic levels
Conclusions du Jour • Small predation increases in ICM do not affect production due to enhanced nutrient recycling. This may be a model artifact and requires additional investigation. • Increased menhaden biomass represented in Ecopath does not have major impacts on higher trophic levels.