Response to domestication and selection for growth in the European sea bass (Dicentrarchus labrax) in separate and mixed tanks

Abstract

Selective breeding of European sea bass (Dicentrarchus labrax) receives a growing interest, as the estimated heritability of growth is medium to high. In this study, we compared the offspring of four groups of sea bass sires, mated with the same wild dams: wild (W), first generation of domestication (D), first generation of mass selection for length (M), first generation of PROSPER-like selection for length (P). The comparison was done both in replicated tanks (separate rearing) and in mixed tanks (mixed rearing) where sire origins were recovered by genotyping of eight microsatellite markers. Weight, length and growth rate were measured from day 238 post-fertilization (69 g mean weight) to day 611 post-fertilization (390 g mean weight). Both in mixed and separate tanks, both selected groups (P, M) were larger than unselected groups (W, D). No difference was seen at any time between W and D, nor between M and P. The selection response estimate on weight was larger in mixed tanks when compared to separate tanks (+ 42% in mixed tanks, + 23% in separate tanks at day 611), yielding realized heritability estimates of 0.60 and 0.34, respectively, and confirming the excellent potential of the species for growth improvement through selective breeding. Both selection response and the amplification effect between mixed and separate tanks decreased as rearing density increased. Our hypothesis is that selection response is magnified by competition in mixed tanks, while sub-optimal rearing conditions lower the observed selection response, more in separate tanks (where selected thus larger fish are at a higher density than unselected ones) than in mixed tanks (where all fish experience the same density effects).

Cuttlebone calcification increases during exposure to elevated seawater pCO2 in the cephalopod Sepia officinalis

“…During long-term exposure to high levels of hypercapnia (*1,000 Pa), teleosts maintain control growth rates; however, the frequency of calcareous precipitates observed in the kidneys, i.e. nephrocalcinosis, has been found to increase (Anarhichas minor, Foss et al 2003;Salmo salar, Fivelstad et al 1999Hosfeld et al 2008; Dicentrarchus labrax, Vandeputte et al 2009). Similarly, elevated calcification has also been observed in otoliths, where otolith mass increased by 25% in 7-day-old larvae of Atractoscion nobilisi raised at 260 Pa CO 2 (Checkley et al 2009).…”

Are sex ratios in wild European sea bass (Dicentrarchus labrax) populations biased?

“…Moreover, at a similar age, females are larger than males (Saillant et al 2001). Finally, as selective breeding of sea bass becomes a reality, with high potential gains in productivity (Vandeputte et al 2009), a good balance between males and females in the populations is needed to allow efficient selection of both sexes.…”

Self-feeding behavior changes induced by a first and a second generation of domestication or selection for growth in the European sea bass,Dicentrarchus labrax

“…The details of rearing conditions and sizes of these populations can be found in Vandeputte et al (2009). In summary, the four tested populations were hatched and reared at the experimental research station of Ifremer in Palavas-lesFlots (France).…”

“…Sea bass was only recently domesticated, so very little is known about the effects of the early steps of domestication or selection for growth, apart from effects on the classically-measured traits of commercial interest (Dupont-Nivet et al 2008;Vandeputte et al 2009), and specifically, little is known about behavioral responses to stress exposure and welfare potential. The authors have already evaluated the behavioral changes induced by a first step of domestication or selection for growth in the European sea bass (Millot et al 2010).…”