The effect of salinity on larval development of spider crab Libinia spinosa (Brachyura, Majidae) reared in the laboratory

Abstract

Ovigerous females of Libinia spinosa were collected in the oceanic region adjacent to the Patos Lagoon and were maintained in the laboratory at 20° and 30 PSU until spawning. After hatching larvae were transferred to compartmented plastic boxes of approximately 25 ml with filtered sea water of different salinities (25, 30 and 35 PSU) and kept under photoperiod of 12 h light: 12 h dark. Water was changed every other day, and larvae were checked daily to assess molt and death rates. Larvae were fed Artemia sp. nauplii newly hatched. Survival to megalopa was higher at salinitiesof 30 and 35 than at salinity 25. Although larvae reached megalopal phases in all three salinities mortality was 100% during this phase. Salinity had no effect on duration of zoea stage I whereas development of zoea II was significantly delayed in the lowest salinity tested. The results obtained were compared to other species of the same genus which were maintained under similar conditions. Nevertheless, there is a difference between the larval development length reported in another study for this species, where the mean length of larval stages was longer.