The health ministry has issued a warning to pregnant women not to eat broad-bill swordfish and certain types of sea bream more than twice a week because mercury in the fish can be harmful to fetuses.
The Health, Labor and Welfare Ministry is also advising pregnant women to limit consumption of shark and sperm whale meat to no more than once a week and bottlenose dolphin to no more than once every two months.
It is the first time the ministry has issued such warnings on consumption of specific types of marine products.