Invasion genetics of Pacific oyster Crassostrea gigas shaped by aquaculture stocking practices

• Published in: Journal of Sea Research
• Main Authors: Moehler, Jenny, Wegner, K. Mathias, Reise, Karsten, Jacobsen, Sabine
• Format: Article in Journal/Newspaper
• Language: English
• Published: Elsevier 2011
• Subjects: British Columbia; Canada; Pacific; Crassostrea gigas; Pacific oyster
• Online Access: https://oceanrep.geomar.de/id/eprint/12594/; https://oceanrep.geomar.de/id/eprint/12594/1/JSR.pdf; https://oceanrep.geomar.de/id/eprint/12594/2/tables-1.xlsx; https://doi.org/10.1016/j.seares.2011.08.004

As a result of aquaculture activities Pacific oysters Crassostrea gigas (Thunberg, 1793) have invaded the European Wadden Sea. Using a variable noncoding mitochondrial marker, we show that the invaded range is the result of two independent invasions. Haplotype frequencies point towards two separate groups, one in the southern and the other in the northern Wadden Sea. We found virtually no genetic differentiation throughout the southern range and the putative source from British Columbia, Canada, suggesting that the Southern region can be considered as a closed population. In the North, mismatch distributions, haplotype ordination and isolation-by-distance analysis suggest a stronger, persistent impact of aquaculture on invasive populations. Due to the ongoing supply of new genetic material from hatchery production the northern invasive populations can therefore be considered as an open population highlighting the importance of aquaculture practice on the genetics of this keystone invader in the Wadden Sea. Highlights: ► Invasions of Pacific oysters into the Wadden Sea are genetically distinct. ► Aquaculture provides constant input of new genetic material into the northern range. ► No significant genetic differentiation was found throughout the southern range. ► Aquaculture practice has strong effects on population demographic parameters.