Kin-structured subpopulations in Eurasian perch (Perca fluviatilis L.)

Based on ecological and behavioural studies it has been assumed that Eurasi an perch (Perca fluviatilis) within one lake may not represent one panmicti c population, but that they are subdivided into subpopulations. In order to investigate the genetic substructuring of populations, we used gene freque ncies of five microsatellite loci to compare perch from six different sites from Lake Constance, Germany, and as outgroups perch from the lake Grosser Vatersee, Berlin, and two Swiss lakes, Lake Zurich and Lake Walensee. We e xamined whether homing behaviour of subadults to the spawning sites of thei r parents occurs and whether philopatric behaviour of adults results in sig nificant population genetic substructuring. The distribution of genetic var iation revealed two major, genetically distinct populations in Lake Constan ce: one in the eastern part of the lake and another in the western part (G( ST)=0.07). Within each of these two populations, no further genetic substru cturing, nor any indication of inbreeding could be detected, either because genetic exchange was sufficiently high or because the time since separatio n has been too short. Homing behaviour of subadults to parental spawning si tes after having spent several weeks of their life cycle in the pelagic zon e could not be detected. Instead, subadults stay within either the western or the eastern region of the lake. There is evidence that some shoals conta in full- and half-sibs. Despite females spawning in close proximity to each other, some siblings stay together. This might suggest that perch possess kin preferences and kin recognition.