CS35 Trophic Dynamics
Date: Wednesday, June 12, 2002
Location: Poster Session - VCC
 
PerezMF, Shannon Point Marine Ctr., Western Washington Univ., Bellingham, USA, kika@mindspring.com
Sulkin, S, , Shannon Point Marine Ctr., Western Washington Univ., Bellingham, USA, sulkin@cc.wwu.edu
 
TOXIC AND NON-TOXIC DINOFLAGELLATE INGESTION AND DISCRIMINATION BY FIRST STAGE BRACHYURAN CRAB LARVAE FROM THE PUGET SOUND
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Brachyuran crab larvae (zoeae) may be an important link in the coastal marine food web, feeding on mesozooplankton and microbial sources, and providing nutrition to fish larvae and other organisms. Though larvae derive optimal nutritional benefit from mesozooplankton, bacterially enriched detrital particles and protists may provide them essential nutrients between encounters with dense mesozooplankton patches. Moreover, zoeae discriminate among protists, ingesting some and rejecting others, including toxic and non-toxic strains of dinoflagellates. We fed a variety of toxic and non-toxic dinoflagellates to first stage larvae of brachyuran crabs Cancer magister, Cancer oregonensis, and Hemigrapsus oregonensis. While both toxic and non-toxic strains of Alexandrium tamarense and Alexandrium fundyense were rejected, toxic Alexandrium andersoni cells were ingested, resulting in accelerated death of the larvae over unfed controls. We also quantified the rates of ingestion of various dinoflagellate prey, including Prorocentrum micans, Alexandrium andersoni, and Prorocentrum dentatum. These experiments provide new information on prey discrimination by crab larvae, whether they feed continuously or become satiated, and whether ingestion rate varies with prey concentration.