Analyse van genmigratie bij de grondel Pomatoschistus minutus (Pallas, 1770) in de zuidelijke Noordzee en Westerschelde aan de hand van microsatelliet merkers
Larmuseau, M.H.D. (2005). Analyse van genmigratie bij de grondel Pomatoschistus minutus (Pallas, 1770) in de zuidelijke Noordzee en Westerschelde aan de hand van microsatelliet merkers. MSc Thesis. Katholieke Universiteit Leuven. Faculteit Wetenschappen: Leuven. 101 pp.
Marine fishes maintain large effective populations, have a high potential for larval dispersal and are highly fecund. Nevertheless, numerous studies detected fined scaled geographical population structuring in highly mobile marine species. The marine environment shows much more heterogeneity than expected, which affectsdispersal; furthermore the genetic structuring is enhanced by certain biological traits as phylopatry and homing. This study was carried out to determine the genetic variability and the temporal stability of population structure of a high gene flow marine goby Pomatoschistus minutus (Pallas, 1770) (Gobiidae, Teleostei).Samples of sand goby were collected in six different localities along the French-Belgian-Dutch coast including the Schelde Estuary in two different seasons both in 2004. Genotyping at seven microsatellite loci revealed very high polymorphism and high expected heterozygosities but it also showed a significant deficiency for heterozygosities in all analysed populations and loci. The genetic differentiation between all populations is weak (FST= 0,009) but statistically highly significant (p< 0,01). There was also an apparent trend of isolation by distance along the coastline. However, significant temporal differentiation was observed within the populations, which does not confirm the persistenee of population structure over time. This study thus proposes that the adopted-migrant hypothesis with a high degree of exchange between neighbouring populations (patchy metapopulation) provides a realistic hypothesis to explain the present population genetic structure of sand gobies. As expected, there is evidence that the Schelde Estuary is a nursery area for juvenile sand gobies. However, the sample collected in Doel during spring had a different status. So further investigation must prove if there is a resident population in the Westerschelde. The microsatellite analysis thus yielded some evidence for small-scale population structuring, although patterns remain difficult to interpret. However, more work with a better sampling strategy and other types of genetic markers, is needed to elucidate genetic relationships among populations and to investigate the function of the Schelde Estuary for the sand goby in the southern North Sea.
All data in the Integrated Marine Information System (IMIS) is subject to the VLIZ privacy policy
