Seasonal metabolic and oxidative stress responses of commercially important invertebrate species—correlation with their habitat

Abstract

Habitat conditions play a crucial role in food acquisition and the energetic and physiological performance of marine organisms during seasonal changes. However, across a wide distribution, populations of the same species might face physiological constraints driven by the oceanographic and climatological characteristics of their habitats. In the context of climate change, biochemical and metabolic data may be important in identifying marine areas in which inhabiting organisms are more or less physiologically constrained. As a first step in identifying such marine areas on the Greek coast, we studied the seasonal metabolic and antioxidant responses of blue crab Callinectes sapidus, cuttlefish Sepia officinalis, sea cucumber Holothuria tubulosa and clam Venus verrucosa, collected from 3 different Greek gulfs: Thermaikos, Pagasitikos and Vistonikos. Seasonal analysis of metabolic responses was based on the activity of the following intermediary metabolic enzymes: lactate dehydrogenase (L-LDH), octopine dehydrogenase (ODH), β-hydroxyacyl-CoA dehydrogenase (HOAD) and citrate synthase (CS). Antioxidant responses were based on the activities of the following enzymes: superoxide dismutase (SOD), glutathione reductase (GR) and catalase, and on lipid peroxidation estimation. The blue crab and clam exhibited the most significant seasonal changes compared to the sea cucumber and cuttlefish, which exhibited no changes. The intermediary metabolism enzymatic activity of blue crab and clam decreased and antioxidant enzymatic activity increased during summer. Higher activity levels for all examined species were observed in Pagasitikos and lower levels in Vistonikos Gulf, indicating corresponding oxidative stress. These results are correlated with the spatial oceanographic conditions of the habitats and are discussed based on future projections of global warming in the Mediterranean Sea.