Detection of zooplankton prey in squid paralarvae with immunoassay

Sustainable management of economically important squid requires monitoring of changes in their abundance, which are related inter alia, to their succe ss in the food chain. The highest mortality is expected in the paralarval s tages, which are prone to starvation. Causes of starvation may be linked to the lack of suitable prey. A multiple detection system was developed for t he simultaneous identification of five putative zooplankton prey in the gut s of paralarval Chokka squid, Loligo vulgaris reynaudii, by employing polyc lonal rabbit antisera in conjunction with solid phase immunoassays. Specifi cities of antisera were validated by ELISA screening against different zoop lankton taxa. Cross-reactions observed with ELISA were minimized through ma nipulation of antibody and antigen concentrations resulting in more specifi c detection of target prey antigens when used in an immunodot assay. Applic ation of this optimised immunoassay detected multiple predation in paralarv al squid samples collected from diverse areas in the Agulhas Bank ecosystem on the south coast of South Africa.