First natural spawning of wild-caught premature south pacific bonito (Sarda chiliensis chiliensis, Cuvier 1832) conditioned in recirculating aquaculture system and a descriptive characterization of their eggs embryonic development

Abstract

This investigation revealed the first biological bases of embryonic development until the hatching of South Pacific bonito Sarda chiliensis chiliensis eggs. The characteristics and stages of embryonic development were described until the hatching stage. The eggs were obtained by natural spawning from wild-caught broodstocks that were conditioned to captivity for more than 1 year in a 75 m3 marine land-based aquaculture recirculating system in Chile. The water temperature range in the broodstock RAS, during the natural spawns events, was between 18.6 °C and 19.8 °C in December 2012, between 20.4 °C and 21.2 °C in January 2013, between 21.5 °C and 22.4 °C in February 2013, and between 21.90 °C and 22.87 °C in march. Incubators’ water temperature was kept similar, through daily water exchanges, to the temperature recorded at the broodstock tank to lessen thermal stress which could affect the embryonic development. Thirty-one embryonic stages were characterized in 71.83 h until eggs hatching. Five periods of embryonic were distinguished: morula, blastula, gastrula, neurula, and metamery. Translucent telolecitic eggs hatched on the third day of incubation, and which was comparatively longer than reported for Atlantic bonito Sarda sarda and the eastern Pacific bonito Sarda chiliensis lineolata. The morphometric data with the most significant variability between the stages of embryonic development were: the length and height of the head, and the length and height of the eye. These are the first embryonic development studies conducted with eggs naturally spawned from wild-caught Sarda chiliensis chiliensis.