Climate change has taken another victim, the ocean fish. Scientists from University of Aberdeen established that some of the most commonly consumed fish species including herring, whiting, and haddock, have reduced in size by nearly 30% for the period of the last 40 years.
The study published in the latest issue of Global Climate Change reveals that the main reason for this drastic decrease in body size is the raise of sea temperatures.
The team led by Alan Baudron looked at eight commercial fish species commonly found in the North sea, and analysed the changes in their body size over the years between 1970 and 2008. For six out of the eight species the findings were shocking, and the only reasonable explanation was the increase of sea temperature by up to 2 degrees C over the examined period. Although there are many other factors that might have caused this such as low food supply and pressure from commercial fishing, climate change was found to be the most significant.
The conclusion was justified by the fact that changes in temperature were the only common factor affecting all six different species. The scientists explain that if the temperatures are lower during the early stage of development, the fish reach maturity a lot later, hence they grow a lot bigger. If temperatures are higher, however, the fish stop growing much earlier. In addition, warmer waters contain much lower concentrations of oxygen, which has been previously found to affect fish body size.
The news came as a surprise to some, who that work in the field. To date, the only known response of fish to climate change has been changes in distribution. If increase in temperatures has this effect now, one can only wonder what will happen to the ocean fauna as the situation worsen as predicted.
Image (c) National Geographic