By the year 2100 nearly 60 percent of marine and freshwater fish species may encounter temperature conditions of the environment in which it will be impossible for their reproduction. According to the study, published in the journal Science, the most sensitive to warming water fish is on the stages of the embryo and spawning adult. The authors noted that a limitation of anthropogenic emissions of greenhouse gases will reduce the number of species of fish at risk to 10 percent.
Fish is the main source of protein for more than three billion people around the world, and with population growth the importance of this resource will increase. Human impact on the environment, especially associated with climate change may lead to greater risks for populations of many fish species, because they are poikilothermic organisms, and water temperature changes will inevitably impact on their metabolism.
Already establishedthat many species of marine organisms has shifted their habitats from the equator toward high latitudes, while the recent forecast of scientists have indicated the possibility of the extinction of 15 percent of species in tropical latitudes of the World ocean. These studies indicate the importance of studying the temperature tolerance of fish, and the need to consider the risks at all stages of their life cycle, as different stages changes the body’s need for oxygen.
Scientists under the leadership of Flemming Dahlke (Flemming T. Dahlke) from Institute for polar and marine research Wegener studied the temperature tolerance of the 630 species of marine and freshwater fish that live in the major latitudes of the world (excluding deep-sea fish living at a depth below 500 feet from the surface, as there is no accurate data on the spawning grounds). To do this, they summarized the empirical evidence on the existence of individuals of these species in changing temperature conditions of the natural habitat. The focus on all four life-cycle stages: embryos, larvae, adults outside the process of reproduction and adults, ready to spawn.