Nutrient removal by age-0 Atlantic menhaden (Brevoortia tyrranus) in Chesapeake Bay and implications for seasonal management of the fishery

Yearly migrations of catadromous herbivorous fish such as the Atlantic menhaden (Brevoortia tyrranus) may constitute a significant mechanism for the transport of organic materials out of estuarine areas. Assessments of nutrient budgets in these estuaries, including Chesapeake Bay, acknowledge the potential importance of this mechanism but exclude it from quantitative analyses because few data exist. Advances in the understanding of bioenergetic processes of many species of fish and development of tools to simulate fish consumption and growth provide an opportunity to quantify the importance of fish dynamics in ecosystem processes. This paper presents a STELLA simulation model of age-0 Atlantic menhaden bioenergetics and fishery dynamics over a single season using field and laboratory data from the literature. The model simulates growth and consumption of age-0 Atlantic menhaden over a 183 day period during which they are abundant in Chesapeake Bay. A fishery management submodel is used to investigate the effects of changing fishing mortality dynamics. The monetary value of the fishery is estimated as a traditional commodity and in terms of the ecological service it provides as a consumer of the products of eutrophication. The simulation shows that age-0 Atlantic menhaden could consume 1.5–119% of total annual primary productivity in Chesapeake Bay and that seasonal harvesting at present levels has a moderate effect on the level of consumption that could potentially be exhibited by the fish at its present estimated population size.