A new study revealed that the size of fish is relatively shrinking due to global warming and climate changes threatening the environment.
The rise in ocean water temperature causes small plankton (microorganisms that fish feed on) to move to the surface, which means that fish do not get enough nutrition.
The University of Tokyo researchers analyzed the individual weight and total biomass of 13 species of fish, including mackerel and sardines, and looked at long-term data for six groups of fish between 1978 and 2018, while studying seawater temperature data between 1982 and 2014 to see the potential impact of changes. In the surface and subsurface layers of the ocean.
The results, published in the journal Fish and Fisheries, showed a clear decrease in fish weight in the 1980s and at the beginning of 2010.
The initial decrease in weight was attributed to an increase in Japanese sardine numbers, which led to increased competition with other species for food.
But closer analysis revealed that climate change, which has warmed the oceans, has led to more competition for food as nutrients rise to the surface layers.
Professor Shin-ichi Ito, from the University of Tokyo, said: “Climate change could affect the timing and length of phytoplankton growth, the massive growth of microscopic algae on the ocean surface, which may not align with key periods of the fish life cycle. It has also been shown in other studies that migration “Fish are affected, which in turn affects fish interactions and competition for resources.”
The team explains that the findings have implications for fisheries and policymakers trying to manage ocean resources under future climate change scenarios.