Award: OCE-1924599

The centerpiece of this project was to document the global spread of the Pacific oyster (*Magallana gigas*), one of the most widely aquacultured species in estuaries on the planet. Although this oyster has been deliberately shipped around the world to establish farms, records describing the sources of these introductions are scarce and information about species co-dispersed with oysters is especially lacking. We used genotyping of single-nucleotide-polymorphisms (SNPs) to map the oyster’s native population structure in Japan and match those genetic signatures to populations now found in Europe, and the Americas. We found that oysters introduced into new regions tend to thrive in environments similar to their native climate, suggesting environmental matching shapes invasion the oyster’s success. We developed a novel statistical framework based on Approximate Bayesian Computing to compare the genetic patterns in 14 other nonnative species found alongside the oysters and statistical address whether oyster transport or commercial shipping was a more likely pathway for each species’ spread. For several of these species, the oyster trade itself was the strongest explanation, highlighting how intentional species movements can inadvertently carry additional organisms around the globe. The authors propose that similar genetic and historical modeling could clarify invasion histories for many other transplanted organisms, improving management and prediction of future invasions.

This funding also facilitated studies that advanced our knowledge of genetic diversity, local adaptation, gene flow, and demographic history during invasions, in host–parasite interactions, and across environmental gradients. The taxa include the annelid Diopatra cuprea, the crustaceans Ampithoe valida and intertidal barnacle Balanus glandula, a haplosporidian oyster parasite Bonamia, and the non-native seaweed Gracilaria vermiculophylla, and foundation salt marsh plant Spartina alterniflora. The project facilitated the development of skills in molecular biology techniques and bioinformatics for several undergraduate and graduate students, and created a network of international scientists that work on estuarine oyster biology and ecology. 

 

Last Modified: 01/08/2026
Modified by: Erik E Sotka