Study links climate change to decreased fish weight in oceans
Climate change may be causing more competition for food in oceans, leading to a reduction in the weight of fish, according to a study. Researchers at the University of Tokyo in Japan found that fish weight in the western North Pacific Ocean dipped in the 2010s due to warmer water limiting food supplies.
They attributed the first period of weight loss to greater numbers of Japanese sardines, which increased competition with other species for food.
«With higher temperatures, the ocean's upper layer becomes more stratified, and previous research has shown that larger plankton are replaced with smaller plankton and less nutritious gelatinous species, such as jellyfish,» Professor Shin-ichi Ito from the University of Tokyo said.
«Climate change can alter the timing and length of phytoplankton blooms, which may no longer align with key periods of the fish life cycle. The migration of fish has also been shown to be affected, in other studies, which in turn impacts fish interaction and competition for resources,» the researcher added.
During the 2010s, the effect of climate change warming the ocean appears to have resulted in more competition for food, as cooler, nutrient-dense water could not easily rise to the surface, the researchers said.
The results, published recently in the journal Fish and Fisheries, have implications for fisheries and policymakers trying to manage ocean resources under future climate change scenarios.
According to the UN Food and Agriculture Organization, in 2019, the western North Pacific
