Climate warming promotes Pacific oyster (Magallana gigas) production in a subarctic lagoon and bay, Japan: Projection of future trends using a three dimensional physical-ecosystem coupled model

Abstract

Bivalve aquaculture is a major industry supporting food production in coastal areas. Although sea water temperature increase due to climate change is expected to affect marine ecosystems in a variety of ways, it is important to determine whether changes in water temperature and associated changes in the trophic conditions will enhance or inhibit the production of bivalves. In this study, I conducted a field survey of environmental factors and growth rates of the Pacific oyster (Magallana gigas) in the subarctic estuarine areas (Akkeshi-ko Lagoon and Akkeshi Bay) and evaluated the effects of climate warming using numerical simulations. In situ cage experiments with two different year-classes were conducted and oyster growth varied between the two stations in the 2nd year-class mainly in response to spatial variation in water temperature. A three dimensional physical-ecosystem coupled model including a growth model of oyster was applied and the model could reproduce the differences in present (the year 2014) growth patterns between stations. The climate warming scenarios showed that oyster production would increase in both lagoon and bay. However, the timing and location of weight loss due to spawning will differ, so caution will need to be exercised regarding the timing of the oyster harvest in the future.