Effects of body weight and temperature on feed intake, gonad growth and oxygen consumption in green sea urchin, Strongylocentrotus droebachiensis

The current study describes the metabolic performance of adult green sea urchin Strongylocentrotus droebachiensis in terms of oxygen consumption, feed intake and gonad growth in relation to body weight and temperature. The experiments were conducted at six constant temperatures (4, 6, 8, 10, 12 and 14 °C), and with three body size groups, i.e. small (S, 40 g), medium (M, 65 g), and large (L, 100 g). Results show that 10–12 °C is the optimum temperature for gonad growth for 40–100-g green sea urchin during summer/autumn, and that there is an inverse relationship between optimum temperature and size. Contrary to gonad growth, both feed intake and oxygen consumption continued to increase throughout the entire temperature range (4–14 °C). The Q10 values for oxygen consumption of fed animals were in the normal range (1.72–3.01), while the corresponding values for starved animals were low (1.17–1.36), indicating negligible effects of temperature on aerobic metabolism during starvation. The energetic analyses indicate a poorly developed regulation of energy intake in relation to energy expenditure.The oxygen consumption data from this study can, together with a still missing description of the relationship between oxygen saturation and somatic and gonad growth, be used to evaluate the water requirement of green sea urchin in aquaculture.