Postdoctoral Researcher, Ecosystems Center, Marine Biological Laboratory
Recently work has shown that saltmarshes are susceptible to nutrient enrichment even in the absence of anoxic/hypoxic conditions. Nutrient induced habitat change in combination with rising sea level could have major consequences for salt marsh productivity. Currently, our knowledge of these impacts on fish production is limited. We examine the effects of moderate nutrient enrichment on the production mummichog, Fundulus heteroclitus, as part of a 9-year whole ecosystem experiment in a New England, U.S.A saltmarsh. In the initial stages of nutrient enrichment we observed a classic bottom up stimulation response in fish production. However, after the first six years fish production declined rapidly. The mechanism for the decline is not known but we hypothesize indirect interactions with other saltmarsh consumers may play an important role. Our results demonstrates that long-term nutrient enrichment can have complex impacts on the production of saltmarsh fish with major implications for food web connections with the coastal ocean and ultimately fisheries production.