Effects of temperature on hatching rate and early larval development of longfin yellowtail Seriola rivoliana

Abstract

The longfin yellowtail Seriola rivoliana is an emerging commercial species in aquaculture. However, there is little information regarding environmental conditions and their influence on early larval development that come from natural spawning. Temperature is one of the main factors affecting embryo and larval development. Therefore, the purpose of this research was to determine the impact of different temperatures (16–32 °C) on S. rivoliana hatching rate, larvae quality (survival, growth, yolk sac and oil droplet consumption, protein and lipid contents) and early developmental events (eye pigmentation and mouth opening). Eggs incubated at 23 °C showed the highest hatching rate (75.5%), but the larvae died 24 h after hatching (hah). Nonetheless, larvae cultivated at 24 °C had the highest survival rates at 48 hah and survived without being fed for over 100 hah. The temperature exhibits a direct effect on protein and lipid content, notochord size and oil droplet volume. In S. rivoliana, the larvae notochord size decreased after the oil droplet was more than half consumed, and at the higher temperature the faster the embryo and larvae depleted their endogenous reserves for growth. Finally, after 96 hah, the optimal mouth opening to ingest adequate rotifers for first feeding has been observed at 22 °C, while best eye pigmentation has been obtained at 24 °C. Therefore, we recommend incubating S. rivoliana eggs at 23 °C. After hatching, we suggest adjusting the temperature to 24 °C to increase the survival percentage and start eye development. Ultimately, after 48 h we encourage to low down the temperature at 22 °C to preserve notochordal length and allow faster mouth formation for further feeding. These optimal temperatures could be operated in the aquaculture industry to improve the management of larval development of S. rivoliana in captivity.