Clam response

Fig. 3.7 Clam response to an upstream odor source. They suppress feeding in response to damaged conspecifics or to crabs that have consumed either fish or clams, but not to starved crabs. From Smee and Weissburg (2006b) with kind permission from Springer Science + Business Media...

Thurberg, F.P., W.D. Cable, M.A. Dawson, J.R. Maclnnes, and D.R. Wenzloff. 1975. Respiratory response of larval, juvenile, and adult surf clams, Spisula solidissima to silver. Pages 41-52 in J.J. Cech, Jr., D.W. Bridges and D.B. Horton (eds.). Respiration of Marine Organisms. TRIGOM Publ., South Portland, ME. 

Sicherer et ah (2004) conducted a nationwide random telephone survey of the prevalence of seafood allergies in the United States and a standardized questioimaire. Responses were categorized on the basis of convincing symptoms and self-reported physician confirmation of the allergy. The survey involved 14,948 individuals with 67 reporting reactions to molluscan shellfish including scallops, clams, oysters, and mussels. The self-reported prevalence in this study population was 0.4%. 

Blaise, C., Gagne, F. and Pellerin, J. (2003) Bivalve population status and biomarker responses in Mya arenaria clams (Saguenay Fjord, Quebec, Canada). Fresenius. Environ. Bull., 12, 956-960. 

Jim Detjen of the Philadelphia Inquirer acknowledges the hard feelings and difficulty in confronting these complex stories when he says, "No one wants to sound foolish." Experts are ego-involved in a professional ethic that does not prepare them for quick, simple responses. So, "they clam up." Oftentimes an expert really isn t sure and doesn t want to say, "I don t know." There s a sense that reporters have fried too many experts with a printed, "No comment."... 

In all outbreaks, mussels (M. edulis) were the only shellfish responsible. Mussels were the shellfish with the highest toxin concentration 4.2 pg/g. Only oysters accumulated toxins at levels (2.45 pg/g) comparable to mussels (James et al., 2004). In other shellfish, the concentration detected was much lower scallops (0.40 pg/g), cockles (0.20 pg/g), and clams (0.61 pg/g). 

Like the gastric proteases, digestive cysteine or thiol proteases are active at acidic pH and inactive at basic pH. They are important components of the hepatopancreas of many marine crustaceans, and are responsible for over 90% of the protease activity in the hepatopancreas in short-finned squid (Jllex illecebrosus) (Raksakulthai and Haard, 2001). Cathepsin B is one example of a marine-derived digestive thiol protease. Only a few marine sources have been identified for cathepsin B, including surf clam (Spisula solidissimd), horse clam (Tresus capax), and mussel (Perna perna L.) (Simpson, 2000). 

Although osmo-conformation allows the clam to survive in highly saline environments, the processes of protein synthesis and repair are energy-intensive, and are estimated to cost 20%-25% of total energy expenditure under nonstressful conditions. The energy used to accumulate amino acids in response to environmental elevated salinities is not available for other survival and reproductive purposes, and probably makes the clam susceptible to succumb to other stresses. 

Hess P, Abadie E, Herve F, Berteaux T, Sechel V, Araoz R, et al. Pinnatoxin G is responsible for atypical toxicity in mussels (Mytilus Galloprovincialis) and clams (Venerupis decussate) from Ingril, a French Mediterranean lagoon. Toxicon 2013 75(SI) 16-26. 

Chen, W.Y, and C.M. Liao. 2010. Dynamic features of ecophysiological response of freshwater clam to arsenic revealed by BLM-based toxicological model. Ecotoxicology 19 1074-1083. 

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