Many people enjoy oysters at New years and during the course of the year. In Japan great care is taken to maintain the freshness and in many cases hotels refuse to serve them due to the spreading of norovirus. The virus affects around 267 million people worldwide and causes over 200,000 deaths each year.
In most cases oysters are farmed and held in tanks, and shipped in boxes and kept refrigerated. So the idea of wild caught oysters is similar to Canadian lobster, not reliable or worthy of the consequences. In fact, oysters are mediocre at best after having been kept in boxes and water tanks. It makes no sense to irrigate oysters, eat them fresh or skip them.
Fresh means from the seashore directly with limited tampering or interference. Hyogo Ako is a picture perfect city on Harima-Nada Sea on the Seto inland of Japan off the East China Sea. There oysters are wild caught in the Harimanada waters from Tatsuno to Aioi, large in size and intense with a lots of gusto.