WAKAYAMA, Spring 2007--Masaba Mackerel Exit, Goma Mackerel Emerge--Quiet Ripples of a Shift in the Ocean

WAKAYAMA, Spring 2007--Masaba Mackerel Exit, Goma Mackerel Emerge--Quiet Ripples of a Shift in the Ocean

In 2007, the Japan Meteorological Agency announced the reality of a long-term rise in sea surface temperatures in the seas around Japan, quietly shaking fishermen along the Kinan coast of Wakayama Prefecture. In the rich fishing grounds that stretch along the southern tip of the Kii Peninsula, fatty chub mackerel used to be the mainstay of the fishing industry. Since the 1990s, however, the water temperature has been slowly rising, and the sea temperature at a depth of 100 meters has risen from 15 to 17 degrees Celsius. The character of the sea had definitely begun to change.

As a result, fishermen's nets began to catch tropical sesame mackerel instead of chub mackerel. Mackerel are adapted to cold currents, whereas sesame mackerel belong to the Kuroshio Current system and prefer warmer water temperatures. Thus, a "species shift" was quietly underway at the bottom of the sea.

In 2005, 80% of the mackerel catch in Wakayama Prefecture was dominated by sesame mackerel. However, sesame mackerel has less fat than chub mackerel, and its market price is low because it tends to lose its freshness easily. The local fishing economy, which had been supported by years of experience, was slowly eroding as the "inverse composition" of increased catch and decreased income for fishermen spread.

At the time, Japan was approaching the first commitment period of the Kyoto Protocol, which was to begin in 2008, and people were becoming aware that global warming was not a distant topic, but a "problem at hand. However, the effects of environmental change appear not in mountains and cities, but first in the oceans. Fish will change. Seaweed beds disappear. Fishermen will suffer. It was a change that could be perceived not by theory but by the senses, and it was a harbinger that the ecosystem would begin to shift all together.

The case of Wakayama illustrates that global warming is not merely a matter of "rising temperatures," but has the power to shake food, culture, and lifestyle to their very foundations. Just one or two degrees Celsius change in ocean temperature can change the fish on the dinner table, and alter traditional fishing methods, distribution networks, and the very order of local economies. Climate change is a "silent revolution" that will rewrite the blueprint of not only nature but also society itself.