The effect of climate change on regional fish population

FishIn recent decades, climate change has been a big concern for the world. Everyone from individual countries to scholars and world leaders have been pondering on the fate of the planet, especially in respect to man’s activities. With the UN Climate Change Conference already under way in the city of Doha, Qatar, a new study has revealed that climatic changes could significantly reduce the fish population within the tropics. However, a counter effect would not be a general decline in population but rather a rise in stock in the cooler waters.

The research led by Dr. Julia Blanchard from the University of Sheffield in the UK, has shown that some areas, far from the equator could see a substantial increase in the amount of fish caught per annum, as long as the fisheries are properly managed. Tropical regions on the other hand will see a fall in fish population. The human populations around the coastal tropics depend largely on fish for food security and subsistence, this drastic drop could bring with it very drastic repercussions. An example cited in this research study, is the island of Palau, this nation in the south of the Pacific experienced great loss in primary production; which depends on how much sunlight is converted to living matter that in turn feed the entire ocean population including fish. This sunlight conversion is done by the photosynthetic organisms, algae.

The research which is also part of the QUEST (Quantifying and Understanding the Earth System) Fish project headed by Prof. Manuel Barange of Plymouth Marine Laboratory, adds the Humboldt ecosystem as another area of concern. This area, west of South America, is important for commercial fish meal production, thus if there is a decrease in productivity of fish in this region, the economic consequences could be far and wide reaching. The research paper continues to not however that the predictions are highly indeterminate because it is based on a climatic scenario that most likely will not happen so many assumptions had to be made.

This is a first of its kind exploration that studies the effects of climate change on fisheries in the coastal ocean worldwide and has also taken into consideration, the important role that algae plays in the food chain. Previous efforts have been made, however it has been difficult to capture the level of complexity brought about when details of every species is included, this is due to our limited ecological knowledge.

The basis of this study that makes it stand out is that it considered the universal principle understood for a long time, that there are more of small animals than the big ones in any environment. This mathematical rule that appear to govern the relationship between organisms of various sizes in an ecosystem so much applies to the relation of planktons, small fish, big fish and top marine predators in the food chain. By using the latest IPCC’s climate change projections on how much plankton there will be in a certain future time frame, the research calculated how much energy will be available to support the bigger animals in the ecosystem. This data was translated to projected numbers by representing how food flows to the top of the marine food chain.

This model was tested by comparing it to previous years and the results checked with the average number of fish caught from several countries over the same period. With the simplicity of this model comparisons resulted in a close match for many of the studied regions. The size based model also closely confirmed earlier models outcome on species distribution.

Though it has produced very conclusive results, the researchers are planning to conduct more detailed testing and also compare outputs from the different models. Sources of uncertainties in the models will also be closely examined. Dr. Blanchard and her team will also investigate particular geographical areas to understand how reliable model prediction might be for the local ecosystems and decipher what makes them better. Further research on the effect of climate change on fish population will also seek to record the important complexities for local ecosystems such as coral reefs, something that the current research study did not dwell upon enough to produce concrete outcomes.

Share on digg

Tags: ,

Comments are closed.