Digestive protease activity in planktonic crustaceans feeding at different trophic levels

• Main Authors: Kumlu M., Jones D.A.
• Other Authors: Çukurova Üniversitesi
• Format: Conference Object
• Language: English
• Published: 1997
• Subjects: Homarus gammarus; Copepods
• Online Access: https://hdl.handle.net/20.500.12605/13323

Trypsin-like enzyme activity of the larvae of two planktonic predatory crustaceans, Homarus gammarus and Nephrops norvegicus (Decapoda: Nephropidae) and the omnivorous larvae of Carcinus maenas (Decapoda: Brachyura) were investigated at each larval stage until metamorphosis. Two copepods, herbivorous or omnivorous grazers, Centropages typicus and Temora longicornis (Copepoda: Calanoidae) were also investigated for this enzyme. A comparison of trypsin-like activity in these and other decapod larvae shows a pattern with high levels in herbivores, low levels in carnivores and intermediate levels in omnivores. Herbivorous planktonic crustaceans appear to rely on high digestive enzyme activities to extract nutrients from less digestible algae or particulates, whereas carnivorous larvae have limited enzymatic capacity as they feed at higher trophic levels upon large and easily digestible prey. Omnivorous Carcinus maenas larvae have intermediate levels of digestive enzymes and are able to transfer between herbivorous and omnivorous feeding. We wish to thank Dr D.J. Fletcher, Mr C. Zeng and Sea Zoo, Anglesey (UK) for providing lobster and crab larvae for the present investigations. The first author greatly acknowledges (^ukurova University (Turkey) and Overseas Research Scheme (UK) for providing grants to support this study. Special thanks also to B. Roberts and G. Hughes for their technical assistance during these experiments.