Impact of climate change on temperature-related growth potential of juvenile fish in the western Dutch Wadden Sea

Abstract

Over the last decades, significant changes in the distribution and abundance of fish species are observed in the North Sea region. The ongoing warming trend of the Wadden Sea might drive cold-water species out of the Wadden Sea by exceeding their optimum performance temperature and might give an opportunity for warm-water species to perform well. In the context of the physiology of fish species and temperature conditions of the Wadden Sea, a mechanism is developed to explain changes in the distribution of several fish species. The species of interest are two demersal flatfish species and two contrasting pelagic fish species, respectively, plaice (Pleuronectes platessa L.), flounder (Platichthys flesus L.), Atlantic herring (Clupea harengus L.) and European anchovy (Engraulis encrasicolus L.). Projected temperature conditions of a general estuarine transport model (GETM) of the Dutch Wadden Sea were implemented into a dynamic energy budget (DEB) model, resulting in monthly potential growth maps for the years 2009-2011 of two sizes classes of the four fish species. Summer temperatures exceeded several species-specific optimum temperatures in large parts of the Wadden Sea within the study period, whereby high temperatures limit growth. Growth reduction was not projected in every year since there was interannual variability in temperature-related growth. If temperatures keep rising, which is projected, optimum temperatures will be exceeded more frequently and more pronounced in the Wadden Sea. The observed changes in fish species distribution can be temperature driven since several cold-water species live at their upper thermal limit, besides, temperature conditions become more favorable for warm-water species.