LAUSR

Abstract Diversification of marine species has emerged as a priority in the aquaculture agenda of many countries due to its large industrial potential and as an alternative to overharvested fisheries. Aquaculture diversification entails new challenges during early life stages of candidate species such as survival bottlenecks or body malformations, many of them due to uncoupling between classic diets and early nutritional requirements. Monospecific diets are common in fish aquaculture, e.g. beginning with a rotifer-based diet, followed by a mixed diet of rotifer and artemia nauplii and ending with artemia nauplii and metanauplii until weaning. Despite some success was reported using such protocol in early hake feeding the massive mortality observed as approaching 25 dph makes optimization of early feeding and larval management a current challenge for the domestication of this species. The main goal of this study was to design and test a workflow management system for early feeding of the European hake as a candidate species. The null hypothesis tested was that optimization of rearing settings had no effect on early growth and survival up to 30 dph as compared to classic culture protocols using commercial prey. Absence of prey in 6 dph hake larvae stomachs indicates that their external feeding at 14 °C begins just after that age. Early feeding preference depends on prey size ( A. franciscana Nauplii. Significant feeding specialization on wild zooplankton such as P. intermedius and T. longicornis occurred after 9 dph (Chesson selectivity index = 0.11). Feeding activity was maximal in darkness (D) and medium light intensity (600 lx, MLI) as compared to the lethal light intensity of 1700 lx (HLI). Rotifer-based diets entailed low larvae growth and hake culture unviability after 15 dph but inclusion of wild zooplankton in early diets doubled growth of 30 dph larvae regarding artemia-based diets. The adaptive prey-size diet designed (MiACop) by combining stages of copepods (nauplii, copepodite and adult), rotifer and commercial nauplii of artemia was five-fold superior to the artemia/zooplankton diet all along the first 30 dph larvae culture. The massive cannibalism observed from 25 dph on was related to the absence of an adequate prey size such as that of mysids and euphausiids in combination with semi-dry feed to trigger weaning. Current workflow design for early feeding of the European hake can be helpful to assuring a larger proportion of juveniles entering the weaning phase. Statement of relevance First feeding of the European hake.