The Day Oysters, Salmon, and Cuttlefish Disappear from Our Dining Table

The temperature of sea water continues to rise due to the effects of global warming. The most prominent example is the Sea of Japan, which has risen 1.8 degrees Celsius in the past 100 years. This is more than three times the global average,” said meteorologist Masamitsu Morita.

Each fish has its own water temperature suitable for development. However, global warming has drastically changed the environment, resulting in unprecedented poor catches of fish and shellfish. Salmon and Japanese common squid are particularly noteworthy.

It is said that the water temperature suitable for salmon is 5 to 13 degrees Celsius, while that for Japanese common squid is 14 to 16 degrees Celsius, above which they are unable to survive. According to statistics from the Japan Fisheries Research and Education Organization, the number of salmon returning to rivers in Japan has dropped to about 20% of its peak around 1996. The catch of Japanese common squid has also decreased to about 10%,” said a Fisheries Agency official.

The rise in CO2 concentration, which is believed to be a factor in global warming, has had a devastating effect on shellfish.

CO2 is dissolving into seawater, causing ocean acidification,” said a Fisheries Agency official. This is preventing oysters from building calcium carbonate skeletons and shells, and more and more are dying before they reach adulthood. Hamana Lake, a famous oyster-producing area, suffered a serious poor catch for two years from ’19, which is once in 50 years”.

Acidification is progressing at an accelerated pace, and there are fears that similar cases may occur off the coast of Sanriku. Global warming, the root of the problem, is unlikely to be resolved, and the situation is likely to worsen further. Mr. Morita, the aforementioned expert, says, “The environment is changing.

“It is possible that a ‘species shift’ is taking place as a result of environmental changes. In search of a better environment, fish will shift their habitat over the next 20 to 30 years. If this happens, they will never return to the waters around Japan.”

The situation is changing by the minute, as the fish species shift has conversely led to a bumper catch of yellowtail in Hokkaido.

Japan’s food supply is at a turning point.

From the January 20 and 27, 2023 issues of FRIDAY