MEPS 248:177-185 (2003)  -  doi:10.3354/meps248177

Harpacticoid copepod emergence at a shelf site in summer and winter: implications for hydrodynamic and mating hypotheses

David Thistle*

Department of Oceanography, Florida State University, Call Street, Tallahassee, Florida 32306-4320, USA

ABSTRACT: Emergence (in which benthic animals swim into the overlying water and then return to the seabed) has consequences for issues such as benthopelagic coupling and benthic community organization. Harpacticoid copepods are conspicuous among emergers; however, to achieve a predictive understanding of their behavior will require much further study. In particular, little is known about variability in their emergence among seasons. I report the results of an emergence-trap study done at 18 m depth on a sandy bottom in the northern Gulf of Mexico. Percent emergence was significantly greater in September than in December. In September, near-bottom flows are quiescent, and in December, near-bottom flows are frequently energetic. That emergence was less during the season of energetic flows fits expectations from the literature that energetic flows suppress emergence. In contrast, my observations on gender and life stage of emergers provided no support for the hypothesis that harpacticoids emerge primarily to find mates.

KEY WORDS: Benthopelagic coupling · Emergence · Harpacticoid copepods · Continental shelf

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