Genetic analysis of goldsinny wrasse reveals evolutionary insights into population connectivity and potential evidence of inadvertent translocation via aquaculture

Interbreeding between local and translocated populations of a cleaner fish in an experimental mesocosm predicts risk of disrupted local adaptation

“…Similarly to corkwing wrasse, intraspecific geographic variance in genetic and phenotypic traits has been also reported on goldsinny and ballan wrasse, the other two main cleaner wrasses used by the salmon industry (Halvorsen et al, 2016;Jansson et al, 2017;Leclercq, Grant, Davie, & Migaud, 2014;Sayer, Gibson, et al, 1996). Similarly to corkwing wrasse, intraspecific geographic variance in genetic and phenotypic traits has been also reported on goldsinny and ballan wrasse, the other two main cleaner wrasses used by the salmon industry (Halvorsen et al, 2016;Jansson et al, 2017;Leclercq, Grant, Davie, & Migaud, 2014;Sayer, Gibson, et al, 1996).…”

“…Faust et al (2018) suggested that the proportion of translocated-origin wrasses neighboring a salmon farm in the west coast of Norway may reach almost 40% and our findings provide highly relevant information pertaining to the issue of hybridization and introduction of exogenous genes in such situations. Similarly to corkwing wrasse, intraspecific geographic variance in genetic and phenotypic traits has been also reported on goldsinny and ballan wrasse, the other two main cleaner wrasses used by the salmon industry (Halvorsen et al, 2016;Jansson et al, 2017;Leclercq, Grant, Davie, & Migaud, 2014;Sayer, Gibson, et al, 1996). Hence, considering that millions of cleaner wrasses are annually translocated in Norway (Iversen, 2016) and the UK (Riley et al, 2017) and released inadvertently and intentionally when the net pens are emptied (Blanco Gonzalez & de Boer, 2017), our results should bring awareness of the putative threat pose by wrasse translocations on fitness performance and the long-term evolutionary potential of recipient populations (Araki, Cooper, & Blouin, 2007;Araki et al, 2009;Eldridge & Naish, 2007;Glover et al, 2017;Laikre et al, 2010).…”

“…The northern Scandinavian populations have shown a further pattern of isolation by distance in the goldsinny (Jansson et al, 2017) and a genetic discontinuity ("break") between southern and western Norwegian populations in the case of corkwing wrasse (Blanco Gonzalez et al, 2016). Moreover, apparent translocated individuals of goldsinny (Jansson et al, 2017) and corkwing wrasse (Faust, Halvorsen, Andersen, Knutsen, & André, 2018) have been found in the proximities of salmon farms in Norway, with indication of hybridization with locals for the latter species. Little is known about how translocated individuals fare in their new environment, their mating preferences versus local conspecifics, and potential isolation mechanisms between translocated and local wrasse populations.…”

“…Recent genetic studies of cleaner fishes in northern Europe have revealed marked large-scale population genetic structure, with reduced genetic variability in northern populations (Almada et al, 2017;Blanco Gonzalez, Knutsen, & Jorde, 2016;Jansson et al, 2017;Knutsen et al, 2013;Robalo et al, 2012). The northern Scandinavian populations have shown a further pattern of isolation by distance in the goldsinny (Jansson et al, 2017) and a genetic discontinuity ("break") between southern and western Norwegian populations in the case of corkwing wrasse (Blanco Gonzalez et al, 2016). Moreover, apparent translocated individuals of goldsinny (Jansson et al, 2017) and corkwing wrasse (Faust, Halvorsen, Andersen, Knutsen, & André, 2018) have been found in the proximities of salmon farms in Norway, with indication of hybridization with locals for the latter species.…”

Embryonic development in corkwing wrasse, Symphodus melops

“…In 2017, approximately 20 million wild wrasses were used by the salmon industry (Statistics Norwegian Directorate of Fisheries: http://www.fiskeridir.no/Akvakultur/Statistikk-akvakultur/Akvakulturstatistikk-tidsserier/Rensefisk) despite little knowledge about their biology (Blanco Gonzalez & de Boer, ). Additional concerns revolve around the possibility that translocated wrasses with distinct genetic profiles to recipient populations (Blanco Gonzalez, Knutsen, & Jorde, ; Jansson et al, ) may escape (Espeland et al, ) and spawn viable eggs that may survive the colder temperatures experienced in northern regions (Blanco Gonzalez & de Boer, ; Faust, Halvorsen, Andersen, Knutsen, & André, ). Eventually, they could establish a genetically distinct population and/or compromise the viability and evolutionary potential of the species (Blanco Gonzalez et al, ; Faust et al, ).…”