Fish populations are decreasing, as the oceans are warm, making them a key source of food and income, endangered by millions of people around the world, according to new studies published Thursday
. that people could consistently harvest crops from a wide range of species declined by 4.1 percent from 1930 to 2010, a victim of human-induced climate change. this is 1.4 million metric tons of fish from 1930 to 2010, "said Chris Free, lead author of the Science magazine.
Scientists have warned that global warming will put pressure on world food supplies. a decade But new findings that separate the effects of warming water from other factors, such as excessive fishing, indicate that climate change already has a serious impact on seafood.
"Fish is a vital source of protein for more than half of the world's population, and some 56 million people worldwide are to some extent supported by marine fisheries," said Dr. Freedom
. As the oceans warmed, some regions were particularly heavy. In the north-eastern Atlantic Ocean and the Sea of Japan, during the period of study, the population of fish decreased by 35% .
"Ecosystems in East Asia ha marked the greatest decline in the productivity of the fish industry," said Dr Will. "And in this region there are some of the largest human populations and populations that are heavily dependent on seafood."
Now a researcher at postgraduate education at the University of California, Santa Barbara, Dr Freeborne began a study, and Ph. D. Rutgers University student
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Marine life has been subject to some of the most dramatic effects of climate change. The oceans absorbed 93% of the heat that enters the atmosphere that enters the atmosphere.
A study published in January, also in science, showed that the temperature of the ocean grew much faster than previous estimates.
Against the background of these changing conditions, the fish shifts where they live, in search of desired temperatures. High temperatures of the ocean can destroy both the fish and the sources of food from which they depend.
"Fish are similar to Zlatogurka: they do not like that their water is too hot or too cold," said Malin L. Pinsky. Professor at the School of Environmental and Biological Sciences at Rutgers University and co-author of a new study.
Approximately a quarter of the investigated regions of the fish expanded their range . On the Atlantic coast of the United States, the steady catch of the Black Sea perch has increased by 6% during the period under investigation.
Another quarter of the regions did not see significant changes in fish populations, such as the northwestern Atlantic Ocean, where Atlantic herring abounds.
But half of the regions have not suffered too. The northeast Atlantic Ocean, the birthplace of Atlantic cod, fish and chips, has fallen by 34% in a steady fork.
Most of all, the number of fish populations has decreased, rather than increased over the course of eight decades of research. The researchers focused on sustainable catches using measures developed by the United Nations to quantify the amount of food that can be re-collected from the base fish population. "Fishing is similar to a bank account, and we are trying to live with interest," said Dr. Pinsk.
Several previous studies suggested that climate change would reduce the number of ocean fish in the future, but new research looked at historical data to determine that the decline has already begun.
"This will be one of the pioneering studies that are quoted over and over again," said Trevor Branch, associate professor at the University of Washington School. Water and Fisheries, which were not involved in the study. "Most of what I saw earlier in terms of the impact on climate change was speculative in terms of:" We believe this will be what will happen in the future. A collection of data from 235 fish populations located in 38 ecological regions around the world. Detailed data told them not only where the fish, but also how they responded to the impact of the environment, as a change in water temperature. . These regional analyzes were important because some parts of the ocean warmed up faster than others. 19659002] The data revealed some other trends. Fish populations in the cold parts of their habitats tended to be more expensive than those located in warmer areas – the excess heat was too high for these fish. This was especially worrisome for researchers, since the data they used was less detailed in the tropics. The loss of fish in these regions may have been higher than in those regions where research was concentrated. Researchers have suggested that swaddling has made fish even more vulnerable to temperature changes, damaging their ability to reproduce and damage the ecosystem.
Protection from overfishing and improving overall fisheries management can help, researchers said. But ultimately, according to them, the decision is to slow down or stop climate change.
A separate study, published on Wednesday in the journal Science Advances, found that the limitation of warming to 2.7 degrees Fahrenheit, or 1.5 degrees Celsius, above the pre-industrial level – the goal of the Paris climate agreement – could lead to billions dollars of additional income for fishing all over the world. Much of this will be the case in developing countries, where many people rely on fish for protein. his research. "Fisheries managers must come up with new, innovative ways to measure these changes. This includes reducing the catch limits in warmer years, but it may also include an increase in catch limits in cooler positive years. The availability of regulatory adaptations to climate change will be really important to maximize food supply. "