Biodiversity, conservation and fisheries

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Climate change, in combination with human uses and developments, affects coastal and marine biodiversity, and the coastal and marine ecosystems that provide vital ecosystems goods and services. These ecosystems goods and services underpin sectors like fisheries, tourism, recreation, nature conservation and the varying needs of local communities, residents, and visitors.

Local, artisanal, sport and commercial fisheries will be affected by climate change. These impacts can include higher sea surface temperatures, stratification of the seas and alteration of the food web, which in turn can affect nutrients, spawning and growth of important fish species. In addition, higher sea temperature can facilitate the introduction, and the emigration and immigration of valuable fish species.

Part of the dilemma for fish stocks are difficulties in separating climatic impacts, from impacts of overfishing and increasing destruction of coastal and estuarine habitat, which also need to be highlighted. This parallels the interaction between human uses and developments, and climatic impacts on coasts. There is also a greater likelihood of the introduction and survival of invasive marine species in coastal and marine waters, which can affect the overall ecosystems, health and populations of these ecosystems and important fish species.

Complex interactions between overfishing and climate change could facilitate ecosystem shifts, a recent example of this may be seen in the Mediterranean and other regions. The combination of higher water temperatures, overfishing and nutrient influxes may result in the presence of algal blooms and jellyfish. In the Mediterranean, algal blooms are boosted by nitrate and phosphate influxes from farming and human wastes. Jellyfish also benefit from the reduction in the number of natural predators like loggerhead turtles and the bluefin tuna, which have been drastically reduced by over-fishing. Once jellyfish are predominant, it can be difficult for juvenile fish populations to re-establish that predator-prey relationship. Reduced river flows during hotter summers might also lead to increased numbers of jellyfish near the shore, as freshwater currents no longer keep the jellyfish offshore. The predominance of jellyfish and algal blooms in coastal waters and adjacent to beaches also reduces the attractiveness of tourism for those beaches.

Enclosed shallow seas such as the Mediterranean Sea, Baltic Sea and Black Sea are very vulnerable to warming and other climate changes. On a longer term basis, ecosystem shifts such as jellyfish and algal blooms could be perceived as an indication that the Mediterranean Sea and region is under stress, and that the sea is becoming "tropicalised". The Mediterranean climate, typified by cool wet winters and dry hot summers, may be shifting with related impacts on terrestrial, coastal and marine ecosystems and biodiversity, and the economies and communities they support.

Principles of biodiversity conservation and climate impacts are considered in the Council of Europe paper, Conserving European Biodiversity in the Context of Climate Change. This concern over the interaction between biodiversity and climate change was continued in the recommendations of the European Platform for Biodiversity Research Strategy, which were then introduced to a meeting of EU Nature Ministers in October 2005. Interactions between biodiversity and climate change are also being considered for adaptation measures under second stage of the European Climate Change Programme.


References

Case Study: Climate Change and European Coast and Beach Management, 2006, Completed by M.A.K.Muir for EU-funded Coastal Practise Network (CoPraNet)
The main author of this article is Magdalena Muir
Please note that others may also have edited the contents of this article.