AME 31:267-278 (2003)  -  doi:10.3354/ame031267

Effect of heterotrophic versus autotrophic food on feeding and reproduction of the calanoid copepod Acartia tonsa: relationship with prey fatty acid composition

Elisabetta Broglio1,*, Sigrún H. Jónasdóttir2, Albert Calbet1, Hans H. Jakobsen2,3, Enric Saiz1

1Departament de Biologia Marina i Oceanografia, Institut de Ciències del Mar, CSIC, Passeig Marítim de la Barceloneta 37-49, 08003 Barcelona, Catalunya, Spain
2Department of Marine Ecology and Aquaculture, Danish Institute for Fisheries Research, Kavalergaarden 6, 2920 Charlottenlund, Denmark
3Present address: Western Washington University Shannon Point Marine Center, 1900 Shannon Point, Anacortes Road, Washington 98221, USA

ABSTRACT: We determined the egg production efficiency (EPE: egg production/ingestion) and egg viability of the copepod Acartia tonsa Dana under different heterotrophic and autotrophic diets. EPE was estimated in adult females either as the slope of the linear relationship between specific egg production (EPR) and ingestion rates, or as the quotient: EPR/ingestion rate. The diets, offered in monoculture, were the heterotrophic ciliates Strombidium sulcatum or Mesodinium pulex, the heterotrophic dinoflagellate Gymnodinium dominans, the autotrophic cryptophyte Rhodomonas salina and the autotrophic dinoflagellate Gymnodinium sanguineum. The diets were also analyzed for fatty acid contents and composition, relationships with EPE and reproductive success were determined. Clear differences were found in the fatty acid contents and the composition of the different diets offered, but these differences did not correspond with variability in EPE. However, egg viability was correlated with ingestion of certain prey essential fatty acids; interestingly, our data do not show that ciliates and heterotrophic dinoflagellates are nutritionally superior prey for marine copepods, contrary to general expectations.

KEY WORDS: Copepod · Acartia tonsa · Ciliate · Dinoflagellate · Egg production · Food quality · Fatty acids · Egg production efficiency · Hatching success

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