Implications of climate change for the fishes of the British Isles

Abstract

Recent climatic change has been recorded across the globe. Although environmental change is a characteristic feature of life on Earth and has played a major role in the evolution and global distribution of biodiversity, predicted future rates of climatic change, especially in temperature, are such that they will exceed any that has occurred over recent geological time. Climate change is considered as a key threat to biodiversity and to the structure and function of ecosystems that may already be subject to significant anthropogenic stress. The current understanding of climate change and its likely consequences for the fishes of Britain and Ireland and the surrounding seas are reviewed through a series of case studies detailing the likely response of several marine, diadromous and freshwater fishes to climate change. Changes in climate, and in particular, temperature have and will continue to affect fish at all levels of biological organization: cellular, individual, population, species, community and ecosystem, influencing physiological and ecological processes in a number of direct, indirect and complex ways. The response of fishes and of other aquatic taxa will vary according to their tolerances and life stage and are complex and difficult to predict. Fishes may respond directly to climate-change-related shifts in environmental processes or indirectly to other influences, such as community-level interactions with other taxa. However, the ability to adapt to the predicted changes in climate will vary between species and between habitats and there will be winners and losers. In marine habitats, recent changes in fish community structure will continue as fishes shift their distributions relative to their temperature preferences. This may lead to the loss of some economically important cold-adapted species such as Gadus morhua and Clupea harengus from some areas around Britain and Ireland, and the establishment of some new, warm-adapted species. Increased temperatures are likely to favour cool-adapted (e.g. Perca fluviatilis) and warm-adapted freshwater fishes (e.g. roach Rutilus rutilus and other cyprinids) whose distribution and reproductive success may currently be constrained by temperature rather than by cold-adapted species (e.g. salmonids). Species that occur in Britain and Ireland that are at the edge of their distribution will be most affected, both negatively and positively. Populations of conservation importance (e.g.Salvelinus alpinus and Coregonus spp.) may decline irreversibly. However, changes in food-web dynamics and physiological adaptation, for example because of climate change, may obscure or alter predicted responses. The residual inertia in climate systems is such that even a complete cessation in emissions would still leave fishes exposed to continued climate change for at least half a century. Hence, regardless of the success or failure of programmes aimed at curbing climate change, major changes in fish communities can be expected over the next 50 years with a concomitant need to adapt manag...

Synthesis of thermal tolerances of the common freshwater fish species in large Western Europe rivers

“…biology (different life stages) and temperature. This will be all the more important for any attempt to make trend forecasts corresponding to scenarios of global change, in which it will be necessary to allow not only for seasonal temperature changes but also for a modified hydrological regime (Graham and Harrod, 2009). …”

Transitional states in marine fisheries: adapting to predicted global change

“…These changes are in addition to well-documented climate variability effects on fisheries from changes in temperature, winds and hydrological cycles (Brander 2010). Warming will probably alter the location of critical fish habitat (Brander 2010); competition and predation dynamics (Graham & Harrod 2009); ecosystem functional roles ; food availability (Chase & Liebold 2002); and reproductive success (Edwards & Richardson 2004;Overland et al 2010). Finally, warming trends will also alter ocean chemistry, with potentially negative effects such as ocean acidification and hypoxia (Pörtner 2010) that, given their limited effects to date, we do not consider here.…”

Seasonal and ontogenetic shifts in the diet of Arctic charr Salvelinus alpinus in a subarctic lake

“…As the natural distributions of many species extend towards higher latitudes and altitudes because of global warming (Walther et al 2002), a major concern for aquatic ecosystems is invasive species and their impacts on native fish populations Graham & Harrod 2009). The most common native fish species in high-latitude lakes is Arctic charr (Salvelinus alpinus), which is regarded as a poor resource competitor against sympatric fish species (e.g., .…”