Seasonal Variation in the Biochemical Composition of the Embryos of Callinectes Sapidus Rathbun

Abstract

The biochemical composition of the embryos of Callinectes sapidus, spawned early in the reproductive season in North Carolina waters (water temperature 12–16°C), is compared with embryos spawned later in the reproductive season (water temperatures greater than 24°C). Embryos spawned early in the season (cultured at 16°C) have initially greater lipid levels, an equivalent amount of protein, and a lower carbohydrate and caloric content than embryos spawned later in the season (cultured at 26°C). During development of the 26°C embryos, lipids are utilized at a significant rate, but in the 16°C embryos protein is utilized to a greater extent. Overall, 45% of the lipid and 35% of the protein is utilized during the development at 26°C versus 55% lipid and 34% protein in the 16°C embryos. In the final stage before hatching the embryos at both temperatures have equivalent lipid, protein, and caloric contents. These results are compared with the results of previous studies on crustacean chemical embryology and possible explanations are given for the variations in substrate utilization with respect to seasonal temperature.