Effect of diatom and dinoflagellate diets on egg production and ingestion rate of Centropages furcatus (Copepoda: Calanoida) from a subtropical bay (Bahía de La Paz, Gulf of California).

This study experimentally determined the role of local diatom and dinoflagellate diets and theirfatty acid composition on the survival, ingestion, and egg production rates of the copepod Centropages furcatus from Bahía de La Paz. The fatty acid profiles of the diatoms Odontella longicruris and Chaetoceros sp., and of the dinoflagellates Scrippsiella sp., Gyrodinium sp., and Prorocentrum micans were determined. After incubating at 24 °C in darkness during 24 h, survival within all phytoplankton diets was > 90%. Dinoflagellate diets provided higher egg production (>25 eggs female-1 day-1) than diatom diets (<10 eggsfemale-1 day-1). No significant differences were observed in the ingestion rates when fed dinoflagellates or diatoms, which varied between 400 and 900 ng C copepod-1 h-1. Higher egg production with dinoflagellate diets suggests better food quality, which may be attributed to higher proportions of the fatty acids 18:4 (n-3) and 22:6 (n-3). These results suggest that when C. furcatus predominantly graze on dinoflagellates eggproduction will increase. Higher abundances of dinoflagellates in the La Paz bay could be coupled with higher egg production of the copepod C. furcatus.