Genetic comparison of experimental farmed strains and wild Icelandic populations of Atlantic cod (Gadus morhua L.)

Genetic Analysis of Cultured and Wild Populations of <I>Mytilus coruscus</I> Based on Mitochondrial DNA

“…However, the mtDNA nucleotide and gene diversity were reduced in the cultured population. A slight decrease of genetic variability in cultured populations had been observed in many fish and mussel species (Lundrigan et al, 2005;Pampoulie et al, 2006;Wang, 2007;Kong & Li, 2007;Shu et al, 2008). The reduced genetic variability we observed in the farmed strains is probably due to a low number of successful breeders during the foundation period, similar to a recent bottleneck in terms of impact on genetic variability (Allendorf, 1986).…”

Wild Atlantic cod sperm motility is negatively affected by ovarian fluid of farmed females

“…Second, cultured strains are usually derived from populations foreign to those locally adapted to the farm area. Finally, re duced genetic diversity among individuals can arise due to founder effects, small effective population sizes and genetic drift (see Bekkevold et al 2006, Hutchings & Fraser 2008 for reviews and Pampoulie et al 2006, Glover et al 2010 for examples in cod). In this context, one of the main ecological concerns is that escapee fish hybridize with wild populations leading to introgression of farmed genetic material into the wild pool (as observed in some Norwegian Atlantic salmon populations by Glover et al 2012Glover et al , 2013, potentially lowering wild stock fitness and/or causing the extinction of the original wild genotypes (reviewed by Fleming 1995, Weir & Grant 2005, Ferguson et al 2007, Hutchings & Fraser 2008; see Araki et al 2009 for a study in a fish population).…”

Farmed and Wild Fish

“…Therefore, a genetic selection occurs in captivity even without any intentional pressure by humans. In fi sh, a reduced genetic diversity has been reported in captive stocks when compared to wild populations, attributable to founder effects, inbreeding, arti fi cial selection, and natural selection mechanisms due to survival of the fi ttest (Alarcon et al 2004 ;Blanchet et al 2008 ;Jackson et al 2003 ;Koljonen et al 2002 ;Pampoulie et al 2006 ;Porta et al 2006 ;Withler et al 2007 ) . In fact, natural selection in captivity acts through exclusion of the individuals unable to survive the many stressors posed by the captive conditions (Mignon-Grasteau et al 2005 ) .…”