An ecological tragedy has shocked Japan in recent weeks. Around 1,200 tonnes of sardines and mackerel were found on the sea surface off the fishing port of Hakodate on the island of Hokkaido, spanning more than a kilometre.
"The cause is unknown at the moment. We plan to sample seawater at the site and examine it to find out the cause," Mikine Fujiwara, a local fisheries official, told the newspaper. Mainichi Shimbun a fisherman who has worked in the area for 25 years, told: "I have never seen anything like this before." According to the Guardian, Japanese authorities are trying to determine the reasons.
The hypothesis is that the death of the fish has to do with natural causes, while a connection with the water released into the ocean from the tanks of the Fukushima nuclear power plant is categorically excluded. Both sardines and mackerel are migratory fish and it is likely that as they moved they ended up in a stretch of sea with temperatures too low to allow them to survive.
Sardines and mackerel
The mackerel is a species widespread in the coastal waters of the Mediterranean and the Black Sea, as well as in the North Atlantic, from the Moroccan and Spanish coasts to the Norwegian Sea.
It is also present in Icelandic, Greenlandic waters and off the coast of Canada. It inhabits waters up to 200 meters deep, wintering in deep waters and returning to the coasts in the warmer seasons. During the 20th century, mackerel fishing increased significantly, even reaching the risk of extinction of the western Atlantic population in 1960.
Over the last decades, actions and measures for sustainable fishing strategies have been prepared, the application of which has caused friction between European Community countries, such as Scotland and Ireland, and foreign countries, such as Iceland and the Faroes .
Mackerel is one of the most used and appreciated fish in the Mediterranean diet: it is recommended by doctors for its supply of omega-3 fats, particularly suitable for those suffering from hypercholesterolemia. In addition to being cooked fresh, mackerel is also preserved canned, possibly after smoking, in oil, natural or even flavored with various ingredients such as white wine. Sardines can be found in the eastern Atlantic Ocean between Iceland and Senegal.
It is usually not found further north than the North Sea. It is common in the Mediterranean Sea and rare in the Black Sea and the Sea of Azov. It is a typical pelagic species that lives in open waters without any contact with the seabed and can be found both far from the coasts and, especially during the good season, in shallow and coastal waters. In winter it is found at depths of up to 180 meters.