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Fish in Search of Cooler Waters
Discussion of the effects of global warming often revolve around problems that the Earth will confront in the future, but they often fail to mention the issues that are currently being experienced. Environmental experts offer a long list of risks that global warming will create, including a significant rise in water levels, changes in ocean currents, decertification of land and a loss of many animal species. For many fish in oceans today, these issues of the future are of little consequence, because they are facing a global warming crisis at this very moment. In many parts of the ocean, temperatures have risen by as much as 1°C or 2°C. While this may not seem like a dramatic increase in temperature, it is enough to create changes in the ecological composition of oceans, seas, lakes and rivers throughout the world.
As ocean temperatures continue to rise, many fish have migrated in attempts to find cooler waters; a trend that has caused many environmental issues. One of the most common strategies implemented by fish when confronting warming temperatures is to go deeper in the ocean to find cooler waters. A simple change in ocean depth actually has a great effect on the ecosystems of oceans. As fish populations go deeper into the ocean, predators such as birds and marine mammals are no longer to reach their traditional prey. As a result, many species of seabirds have vanished from locales where they used to flourish. Fish who cannot locally deal with climate change usually attempt to migrate closer to the North and South Pole to find cooler waters. Various species of fish throughout the world have traveled great distances in order to find cooler waters. For example, 21 species of fish in the North Sea have migrated north with cod moving 73 miles north and Arctic haddock moving 65 miles. In addition, Cod, plaice and halibut are moving out of US and southern Canadian waters. These are just two, of the many examples of ocean environments that will be permanently changed as a result of marine species adaptation to global warming.
Dramatic shifts of entire fish populations have a tremendous effect on ocean environments. Apart from effecting fisheries and other human economic interests, migration of fish populations throws off the balance of ocean ecosystems. When new species of fish are introduced into foreign waters they often deplete the resources available to native populations. This problem has been sprouting up in many different areas throughout the world: In the Mediterranean Sea, new species of tropical fish have been spotted; scientists predict that nearly 30 new species of fish will be introduced into the Great Lakes; and anchovies, sardines and other traditionally subtropical fish have found their way into the waters of Britain. Cases such as these will become even more prevalent as the effects of global warming continue to bring about higher water temperatures and ecosystems will struggle to find balance as new species are introduced and others are lost.
The effects of global warming are no longer a case of "if" or "when," for fish populations throughout the world's various bodies of water, the effects of global warming are being felt today. Entire fish populations are being forced to find cooler waters by whatever means necessary. This includes retreating to deeper waters, but at ever increasing rates, the search for cooler waters takes fish far north or south. As fish travel hundreds of miles from their original habitats, marine ecosystems suffer. Whether the motivation is the fishing industry or environmental conservation, these issues need to be addressed and this can be done by fighting global warming.
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