Effects of temperature, diet, and bivalve size on the ingestion of sea lice (Lepeophtheirus salmonis) larvae by various filter-feeding shellfish
文摘
Filter-feeding shellfish could act as biological agents in the control of parasitic sea lice (Caligidae) at salmon farms as a benefit of integrated multi-trophic aquaculture. Determining the extent to which various bivalve species ingest sea lice (Lepeophtheirus salmonis) larvae under controlled laboratory conditions was an important first step towards understanding the potential for shellfish to reduce the number of these copepod larvae in the water column at net pens. A series of laboratory experiments examined the effects of temperature (~ 5, 10, and 15 ¡ãC), diet (larvae alone or with phytoplankton), and bivalve size (small, medium, and large) on the amount of L. salmonis larvae ingested by basket cockles (Clinocardium nuttallii), Pacific oysters (Crassostrea gigas), mussels (Mytilus spp.), and Pacific scallops (unconfirmed hybrid: Mizuhopecten yessoensis x Patinopecten caurinus). Feeding rate was assessed by placing bivalves individually in 2-l containers holding approximately 450 larvae in 750 ml of filtered seawater. Results of the temperature/diet experiments indicated that all four species of bivalves ingested sea lice larvae, regardless of phytoplankton presence or absence, and that temperature had no significant effect on the proportion of larvae ingested. All three sizes of oysters and scallops ingested sea lice larvae, with large shellfish consuming a significantly greater proportion of the larvae than small individuals. Future research, examining the role of bivalves in the control of sea lice, should be continued at a commercial scale at a salmon farm.
