Downstream migration in Atlantic salmon (Salmo salar) smolt sibling groups

Abstract

Previous studies have shown kin recognition abilities in salmonid fish. Some authors have suggested that the attraction of juvenile fish to siblings may indicate preference for shoaling with kin. The aim of the present study is to test the prerequisite for the hypothesis that siblings swim spatially closer than unrelated fish during their seaward migration as smolts. Atlantic salmon (Salmo salar) eggs from three families were each reared in two tanks to create familiar and unfamiliar sibling smolts. Before the experiment started they were tagged individually withpassive integrated transponders (PITs). Twelve individuals from each of six groups were mixed and released together at several occasions in the upper end of the 400-m-long experimental stream. An automatic PIT-monitoring system placed in the outlet recorded the time for passage of each individual leaving the stream. Eighty-five percent of the juveniles monitored by the PIT antenna showed downstream migration at night hours and they migrated significantly more often closer in time to both known and unknown siblings than to unrelated fish. The results suggest that there is a genetic component in the migratory behaviour of Atlantic salmon smolts and support the hypothesis that smolts migrate in kin-structured groups.

Sampling strategies for estimating brook trout effective population size

“…Early (soon after hatching) non-random kin associations have been demonstrated in other stream fishes, including Atlantic salmon (Salmo salar) (Olsen et al 2004;Einum and Nislow 2005), brown trout (Salmo trutta) (Hansen et al 1997;Hansen and Jensen 2005;Carlsson 2007;Sanz et al 2011) and high predation populations of guppies (Poecilia reticulata) (Piyapong et al 2011) and are likely to be demonstrated in future studies of additional species. Population-specific spatial variation in kin associations is likely to vary with environmental conditions and age of the individuals under consideration.…”

Kin assortment in juvenile shoals in wild guppy populations

“…Many investigations of kin recognition in fish have focused on juvenile salmonids and have shown that salmonids are able to recognise kin (see Olsén, 1999 for a review). Experiments using released PIT (Passive Integrated Transponders) tagged smolts of laboratory reared salmon, have shown that siblings swim spatially closer together than unrelated fish during their seaward migration, supporting the hypothesis that smolts migrate in kin-structured groups (Olsen et al, 2004). These studies provide reliable evidence for kin recognition and kin preference both under laboratory and semi-field conditions.…”

Relatedness and polyandry of sixgill sharks, Hexanchus griseus, in an urban estuary

“…A handful of studies have found spatiotemporal kin association in the aquatic environment (Planes et al 1993;Olsén et al 2004;Selkoe et al 2006;Miller-Sims et al 2008;Buston et al 2009;Sikkel and Fuller 2010). Over half these studies found high levels of relatedness among fish within discrete aggregations (Miller-Sims et al 2008;Olsén et al 2004;Sikkel and Fuller 2010). This level of association has been demonstrated in the demersal livebearing black perch, Embiotoca jacksoni (Sikkel and Fuller 2010), the benthic nesting humbug damselfish, Dascyllus aruanus (Buston et al 2009), the midwater aggregate spawning kelp bass, Paralabrax clathratus (Selkoe et al 2006), and the riverine benthic nesting Atlantic salmon, Salmo salar (Olsén et al 2004).…”

“…Alternatively, sharks born in the same location may simply be found together over time because they are similarly associated with their natal habitat. A handful of studies have found spatiotemporal kin association in the aquatic environment (Planes et al 1993;Olsén et al 2004;Selkoe et al 2006;Miller-Sims et al 2008;Buston et al 2009;Sikkel and Fuller 2010). Over half these studies found high levels of relatedness among fish within discrete aggregations (Miller-Sims et al 2008;Olsén et al 2004;Sikkel and Fuller 2010).…”

“…Over half these studies found high levels of relatedness among fish within discrete aggregations (Miller-Sims et al 2008;Olsén et al 2004;Sikkel and Fuller 2010). This level of association has been demonstrated in the demersal livebearing black perch, Embiotoca jacksoni (Sikkel and Fuller 2010), the benthic nesting humbug damselfish, Dascyllus aruanus (Buston et al 2009), the midwater aggregate spawning kelp bass, Paralabrax clathratus (Selkoe et al 2006), and the riverine benthic nesting Atlantic salmon, Salmo salar (Olsén et al 2004). Kinship associations are not generally expected for species with the capacity to disperse long distances and mix randomly during planktonic phases (Selkoe et al 2006;Buston et al 2009).…”