Effects of temperature, density, and diet on development, survival, settlement synchronism, and fatty acid profile of the ornamental shrimp Lysmata seticaudata

The effects of different rearing temperatures, densities, and diets on the larval development, survival to metamorphosis, settlement synchronism, and fatty acid profile of the ornamental shrimp Lysmata seticaudata were evaluated. Survival of larvae raised at 20 degrees C was not significantly different (average+/-standard deviation) (94.8+/-4.5%) from that of those raised at 26 degrees C (85.3+/-9.5%), and presented significantly longer larval durations (31.8+/-1.0 days) than the ones raised at 26 degrees C (19.5+/-1.3 days). Larvae starved in zoea I displayed significantly lower survival (64.7+/-10.0%), and higher numbers of larvae remained in the last zoeal stage and died before metamorphosing. Larvae fed newly hatched Artemia nauplii, Artemia metanauplii or enriched Artemia metanauplii displayed similar survival (85.3+/-9.5%, 81.3+/-5.9%, and 75.5+/-2.1%, respectively) and similar larval stage durations. Larvae cultured at rearing densities of 10, 20, and 40 larvae l(-1) showed similar survival rates (85.3+/-9.5%, 88.0+/-1.8%, and 86.8+/-5.4%, respectively). When cultured at 40 larvae l(-1), a significantly higher proportion of larvae remained in the last zoeal stage (13.5+/-5.9%) 15 days after the settlement of the first postlarva. The survival of larvae fed newly hatched Artemia nauplii, or fed newly hatched Artemia nauplii until zoea V and switched to enriched Artemia metanauplii until settlement did not differ significantly (86.8+/-5.4% and 87.0+/-6.0%, respectively). Both treatments showed similar proportions of late stage larvae that did not metamorphose by the 15th day following the first settled postlarva. With the exception of larvae starved in zoea I, and those cultured at 40 larvae l(-1), that did not display any "mass settlement period," settlement mainly occurred during the 3rd and the 7th day following the settlement of the first postlarva. The fatty acid content of postlarvae cultured under different temperatures (20 and 26 degrees C) and fed the same larval diet (newly hatched Artemia) were similar. With the exception of docosahexaenoic acid (DHA) content, postlarvae fed enriched Artemia metanauplii displayed similar fatty acid content to those displayed by postlarvae fed on newly hatched Artemia and Artemia metanauplii. Wild postlarvae displayed a significantly lower fatty acid content (46.95+/-2.85 microgram/mg dry weight), when compared to cultured organisms. These differences in fatty acid composition were more pronounced on saturated and monounsaturated fatty acids. Wild postlarvae always displayed a significantly higher DHA/EPA ratio (1.01+/-0.13), even when compared with that of postlarvae fed on enriched Artemia.