CHANGES IN VOLUME, BIOMASS, AND FATTY-ACIDS OF DEVELOPING EGGS IN NAUTICARIS-MAGELLANICA (DECAPODA, CARIDEA) - A LATITUDINAL COMPARISON

The hippolytid shrimp Nauticaris magellanica, with a known geographica l distribution covering approximately 35 degrees of latitude, was sele cted to conduct a latitudinal comparison regarding volume, biomass, an d fatty acid changes during embryogenesis. Ovigerous females were coll ected from populations in northern (Guanaqueros) and central-southern Chile (Metri and Putemun). Recently produced eggs from the 3 populatio ns sampled wen: similar in size (ranging from 0.031-0.038 min(3)). Emb ryos close to hatching, however, were considerably larger in central-s outhern Chile (Metri: 0.072 mm(3); Putemun: 0.091 mm(3)) compared with those from Guanaqueros (0.054 mml). Egg volume increase during the in cubation period varied between 74% (Guanaqueros) and 160% (Putemun). W et mass and water content of embryos increased, while dry and ash mass decreased during embryogenesis. Analyses of fatty acids revealed simi lar results for eggs from the 3 study sites and different developmenta l stages. The overall utilization of fatty acids, however, was elevate d in embryos from the most southern location (Putemun) compared with t hat found in embryos from the other sampling sites. Main fatty acids o f eggs and newly hatched larvae were the polyunsaturates 20:5 (n-3) an d 22:6 (n-3), and the saturate 16:0, comprising 21, 16, and 15%, respe ctively, of the total. The pattern of fatty acid utilization during em bryogenesis is characterized by a sharp decline of the 16:1 (n-7) fatt y acid. Our results confirm a latitudinal dine in egg volume in N. mag ellanica. The differences observed among populations may be attributed , however, to differences in the ambient conditions (e.g., temperature , salinity, feeding) of the habitats rather than simply to its norther n and southern location. In addition, the lipid biochemistry of develo ping eggs seems to be unaffected by latitude.