Influence of stocking density and temperature on early development and survival of the purple sea urchin, Strongylocentrotus purpuratus (Stimpson, 1857)

摘要

We evaluated the effect of four densities (940, 1880, 3760, 7520?eggs?cm?2 and 0.5, 1, 2, 4 ind?mL?1 of embryos and larvae, respectively) and four temperatures (8, 11, 14, 17°C) on early growth and survival of the sea urchin Strongylocentrotus purpuratus. Prism-stage length was significantly greater in embryos initially held at 940 and 1880?eggs?cm?2 than in those held at 3760 and 7520?eggs?cm?2. Larvae grew significantly faster and had significantly greater survival when reared at 0.5 or 1?ind?mL?1 than when held at 2 or 4?ind?mL?1. Embryos had greater survival at 11 and 14°C than at 8 and 17°C, whereas embryo length was significantly smaller at 8°C than at 11, 14 or 17°C. Larvae grew significantly slower at 8°C than at 11, 14 or 17°C, whereas survival was significantly reduced at 8 and 17°C compared with 11 and 14°C. Per cent survival from prism to metamorphic competency in the best treatments was 48.9?±?2.2% and 50.0?±?3.6% (mean?±?SE) for the 1?ind?mL?1 and 11°C treatments, respectively. On the basis of these results, for rearing of S.?purpuratus under static conditions, we recommend that fertilized eggs and larvae be held at ≤1880?eggs?cm?2 and ≤1?ind?mL?1, respectively, and at 11–14°C.