MEPS 281:233-239 (2004)  -  doi:10.3354/meps281233

Experimental studies of predation by bluefish Pomatomus saltatrix in varying densities of seagrass and macroalgae

L. A. Harris*, B. Buckley, S. W. Nixon, B. T. Allen

Graduate School of Oceanography, University of Rhode Island, South Ferry Road, Narragansett, Rhode Island 02882, USA

ABSTRACT: We conducted ecosystem level experiments to investigate predator-prey relationships in 3 habitat types; eelgrass Zostera marina, macroalgae, and bare sediment. Mesocosms containing marine sediments, coastal water, and varying densities of eelgrass (75 to 1000 shoots m-2) or macroalgae (50 to 1000 g wet weight m-2) were used to simulate conditions found in shallow coastal lagoons of Rhode Island, USA. We used bluefish Pomatomus saltatrix as predators in each experiment after appropriate acclimation in each habitat type. Prey fish were provided in equally weighted rations and included silversides Menidia menidia, tautog Tautoga onitis, cunner Tautogolabrus adspersus, and menhaden Brevoortia tyrranus. Eelgrass significantly increased the survivorship of silversides, tautog and cunner at very low shoot densities. Experiments using macroalgae did not result in significantly different survival rates between bare sand and macroalgae habitat for silversides or cunner, the 2 species tested for this vegetation type. With the decline of eelgrass and increase of macroalgal cover in shallow coastal areas of Rhode Island, this information increases our understanding of the relative value of eelgrass habitat to fish stocks and should provide added incentive to protect and conserve existing eelgrass beds.


KEY WORDS: Fish habitat · Predator-prey interactions · Habitat complexity · Seagrass · Macroalgae · Bluefish


Full text in pdf format