Karyotypes of three South East Pacific flounder species of the family Paralichthyidae

First-feeding halibut larvae (245-day degrees; 40 days post hatch), reared at 34 g L-1 salinity and 7°C, were subjected to handling and allowed to recover in a range of salinities (0–34 g L-1) and at 10°C. Survival of the unfed larvae was determined daily for 18 days. Mortality rates approached 0 after 4 days in all treatments and presumed starvation-induced mortality started at about 11 days post handling. By 20 days post treatments, all larvae had died. Salinities in the range of 10–20 g L-1 produced significantly (anova, P<0.01) higher initial survival (71–95%) than salinities above 20 g L-1 (24–48%) or below 10 g L-1 (0–19%) and this survival pattern changed little in unfed larvae for the first 10 days following the stressor. For example, 24 hour post handling, survival of halibut was improved from 28.7±16.5% (mean±standard error, n=3) at 34.0 g L-1 to 95.2±4.8% at 13 g L-1. A second-order polynomial regression of 4-day post-handling survival data (y=-0.002 x2+0.0603x+0.0699, r2=0.3936) predicted a maximum survival at 15.1 g L-1 salinity. These results have important implications for halibut aquaculture and research when handling of larvae is unavoidable. For practical applications, we recommend reducing salinity of receiving waters to 15–20 g L-1 with a slow (3–4 days) reacclimation to ambient conditions.