Global change and climate‐driven invasion of the Pacific oyster (Crassostrea gigas) along European coasts: a bioenergetics modelling approach

Abstract

Aim The spread of non-indigenous species in marine ecosystems world-wide is one of today's most serious environmental concerns. Using mechanistic modelling, we investigated how global change relates to the invasion of European coasts by a non-native marine invertebrate, the Pacific oyster Crassostrea gigas.Location Bourgneuf Bay on the French Atlantic coast was considered as the northern boundary of C. gigas expansion at the time of its introduction to Europe in the 1970s. From this latitudinal reference, variations in the spatial distribution of the C. gigas reproductive niche were analysed along the northwestern European coast from Gibraltar to Norway.Methods The effects of environmental variations on C. gigas physiology and phenology were studied using a bioenergetics model based on Dynamic Energy Budget theory. The model was forced with environmental time series including in situ phytoplankton data, and satellite data of sea surface temperature and suspended particulate matter concentration.Results Simulation outputs were successfully validated against in situ oyster growth data. In Bourgneuf Bay, the rise in seawater temperature and phytoplankton concentration has increased C. gigas reproductive effort and led to precocious spawning periods since the 1960s. At the European scale, seawater temperature increase caused a drastic northward shift (1400 km within 30 years) in the C. gigas reproductive niche and optimal thermal conditions for early life stage development.Main conclusions We demonstrated that the poleward expansion of the invasive species C. gigas is related to global warming and increase in phytoplankton abundance. The combination of mechanistic bioenergetics modelling with in situ and satellite environmental data is a valuable framework for ecosystem studies. It offers a generic approach to analyse historical geographical shifts and to predict the biogeographical changes expected to occur in a climate-changing world.The oyster-DEB model was derived from the standard DEB model described by Kooijman (2010) and first applied to C. gigas by Pouvreau et al. (2006). The model equations and parameter values used here are based mainly on the study

Shellfish Aquaculture from Space: Potential of Sentinel2 to Monitor Tide-Driven Changes in Turbidity, Chlorophyll Concentration and Oyster Physiological Response at the Scale of an Oyster Farm

“…For example, the poleward extent of the Pacific oyster (a well-known invasive species, Herbert et al, 2016) along the European coasts has been recently quantitatively analyzed using an original coupling of EO with mechanistic physiological oyster modeling (Thomas et al, 2016). In another recent study the EO time-series archive has been used with climatic, biological and energetics models to better understand predicted changes in growth, reproduction and mortality risk for commercially and ecologically important bivalves in the Mediterranean Sea (Montalto et al, 2016).…”

“…The second objective is to analyze the tide-driven influence of SPM and chl a variability on oyster ecological response at the scale of an oyster farm. For that purpose, and building on previous studies (Gernez et al, 2014;Thomas et al, 2016), Earth Observation (EO) and shellfish physiological modeling were interconnected in order to remotely quantify the influence of rapidly changing environmental conditions on oyster clearance and chl consumption rates.…”

Satellite remote sensing reveals a positive impact of living oyster reefs on microalgal biofilm development

“…In Europe, it was massively imported in the 1970s and rapidly became the main cultivated species, following the decline of previously farmed oysters which had been struck by large-scale epizootic outbreaks (Grizel and Héral, 1991;Humphreys et al, 2014). During recent decades, C. gigas benefited from coastal eutrophication and rising sea temperature (Thomas et al, 2016), resulting in a poleward expansion of its distribution (Dutertre et al, 2010) and the formation of dense reefs along many coastal areas (Diederich, 2006;Brandt et al, 2008;Le Bris et al, 2016). In some ecosystems, wild C. gigas is now considered as a trophic competitor of its cultivated conspecifics (Cognie et al, 2006).…”

Competitive interactions moderate the effects of elevated temperature and atmospheric CO2 on the health and functioning of oysters

“…Information from experimental studies on C. gigas (e.g. Havenhand & Schlegel 2009, Dutertre et al 2010) indicate, with high probability, further spread of this species across Europe, leading to large-scale biogeographic shifts in coastal marine communities (Thomas et al 2016) and potential to outcompete the native oyster O. edulis.…”