Change of Fish Distribution
Change of Global Fish Distribution
Change of Global Fish Distribution
Extinction fish is also increasing and the catch near the equator is decreasing to 50%. In 2050, fish that inhabit the current changes about 60% due to the global warming and catch is greatly reduced in the equatorial ocean. So distribution of fish of the world will be reorganized.
Turbulent species northward
As temperatures have risen in the northeast Atlantic Ocean, fish species with more southern biogeographical affinities, such as hake and dab, have increased in abundance, whereas those with more northerly and boreal distributions, such as cod and haddock, have declined. Grey bars indicate no significant response. Simpson and colleagues show that collectively, such changes have led to a reorganization of local demersal communities in the region, despite limited evidence of range shifts among the species studied. The abundance response to temperature is shown as the coefficient of correlation .
Left picture show change of fish catch on subtropic and temperate ocean. From 1970 to 2006, as open temperatures were rising, catch composition in the subtropic and temperate areas slowly changed to include more warm-water species and fewer cool-water species. Right picture show change of fish catch on Tropics. In the tropics the catch composition changed from 1970 to 1980 and then stabilized, likely because there are no species with high enough temperature preferences to replace those that declined.
These shifts could have negative effects including loss of traditional fisheries, decreases in profits and jobs, conflicts over new fisheries that emerge because of distribution of distribution shifts, food security concerns, and a large decrease in catch in the tropics.
Plunged fish near the Equator and increasing South, Arctic fish
Sea surface temperatures (SSTs) rise fish respond by moving either deeper or to higher latitudes. This was shown clearly in events like the 2011 Western Australian Extreme Marine Heatwave, as well as the steady increase in numbers of sub-tropical fish being caught in temperate fisheries. Overall, our results suggest that change in the composition of marine fisheries catch is significantly related to temperature change in the ocean, with an increasing dominance of catches of warmer waters species at higher latitudes and a decrease in the proportion of catches of subtropical species in the tropics. Such changes in catch composition have direct implications for coastal fishing communities, particularly those in tropical developing countries, which tend to be socio-economically vulnerable to the effects of climate change.
Marine species are gradually moving away from the equator into cooler water, and, as a result, species from warmer water are replacing those traditionally caught in many fisheries worldwide. Scientific studies show that this change is related to increasing ocean temperatures.
As these changes may also affect fish assemblage metrics in use at present for assessment and monitoring purposes, this implies that the reference condition baselines use to assess the ecological status of rivers based on fish would not be adequate in the future.
Empirical evidence of these changes was shown by the study conducted downstream of lake outlet flow in the Traun river. During the last three decades the water temperature increase by on average 2.2 °C in August. This increase led to unsuitable thermal conditions for the grayling (Thymallus thymallus), which was historically present in this area. Consequently the grayling population greatly decline in favour of more adapted species such as barbel
Climate change alters fish assemblage structure and function distribution in Europe
Species distributions are driven by environmental conditions, be it natural landscape settings or environmental stress induced by human activities including Climate Change. The Intergovernmental Panel on Climate Change predicted changes in temperature and precipitation in Europe for the periods 2020-2030 and 2050-2060. These changes are expected to greatly alter the distribution of fish, by providing more suitable habitats for species tolerating or preferring warm water, and by restricting species adapted to cold water habitats; the latter are expected to decline or even go extinct some regions of Europe.
Increasing of the extinction fish
Researchers pointed out that fish, being not able to adapt to global warming, many will face a crisis of extinction. Rock lobster of the Antarctic Ocean and the striped rock cod of the Arctic Ocean is representative. It was expected that damage of fish of the equator, the Antarctic Ocean, the North Atlantic and Northeast Pacific Ocean becomes more pronounced. Possibility of extinction is larger fish species that inhabit the sea surrounded by land as the Mediterranean and the Red Sea. In addition, moving to the North Pole, living in the Arctic Ocean which lies between the continent and the UK "Atlantic cod" is reduced by 20% or more. On the other hand "Europe flounder" lived in south is expected to increase 10% or more.
