Researchers at the University of Tokyo have discovered a troubling trend in the western North Pacific Ocean: fish get smaller. The study hypothesizes that warmer oceans, the consequence of global warming, are the main cause of food scarcity for fish, which eventually reduces their body weight. Over the past decade, the weight of fish in the area decreased significantly and experts believe that this phenomenon resulted from warm waters that constrained food supplies. However, the increase in the number of Japanese sardines, which developed in such a warm environment, caused an additional food resource competition among fish species.
Professor Shin-ichi told that higher temperatures change the ocean structure which affects plankton abundance. Changes in phytoplankton blooms, vital for fish breeding, and disturbances in migration routes interfere with the availability of food for fish and increase the competition for scarce resources. These findings emphasized the need to tackle the threat to marine ecosystems from climate change. Besides measures, the dropping fish weight could imply a critical situation about the marine biodiversity and global food security. Fighting climate change is of high priority to ensure the health of our oceans and fish stocks.