Ecophysiological studies on the ontogeny of euryplasticity in the caridean shrimp, Palaemonetes pugio (Holthuis) and modifications by zinc.

Larvae of the estuarine caridean shrimp Palaemonetes pugio (Holthuis) were reared from hatch through completion of metamorphosis in 80 combinations of salinity (3 to 31 %.), temperature (20 to 35 C), and zinc (0.00 to 1.00 ppm Zn++). Response-surface methodology demonstrated that outside optimal salinity-temperature conditions (17 to 27 %. S and 20 to 27 C), viability of larvae was reduced by both the individual and interactive effects of salinity and temperature. Survival capacity of larvae and resistance adaptations to salinity and temperature were progressively reduced by increasing zinc concentrations. Response-surface analysis of the data suggested that the duration of total larval development of P. pugio was least at salinities from 18 to 23 %. and at temperatures from 30 to 32 C. At both higher and lower salinity-temperature conditions and in increasing zinc concentrations, developmental rates were retarded. Increasing zinc concentrations reduced both survival and developmental rates of larvae more at suboptimal temperatures. Larval resistance to zinc toxicity was least at supraoptimal salinities.