Effects of temperature and salinity during incubation on hatching and yolk utilization of Gulf killifish Fundulus grandis embryos

This study serves to determine the influence of incubation temperature and salinity on egg-yolk utilization and size at hatch in Gulf killifish Fundulus grandis. Variables such as body length, body depth at vent and yolk area at hatch have been viewed as critical aspects for larval survival at first feeding and beyond. Incubation temperatures were maintained at 20, 21.6, 23 and 29 °C using incubation chambers. Incubation trays were filled with 50 mL of water at salinity concentrations of 10 g/L and 20 g/L. Newly fertilized eggs were placed in the incubation trays and checked daily for the presence of newly hatched larvae. The larvae were collected and analyzed by image analysis software to determine the length, body depth and yolk area of each larva. Larvae incubated in lower temperatures had the longest incubation time but were more developed with the least amount of yolk. Conversely, larvae incubated in the highest temperature had the shortest incubation time but were less developed with the greater relative amounts of yolk. Larvae from the 20 g/L salinity trial had a longer mean time to hatch and total length compared to the 10 g/L trial. The results of this study may be used in estimating developmental responses to temperature and salinity. Coordination of hatch times and morphometric traits can be managed through the manipulation of temperature and salinity to achieve desired parameters.