Press Release

July 6, 2015

Fisheries Research Agency

Development of a simple technique for identifying the floating larvae of Japanese oysters

  • We have developed a technique for easily identifying floating larvae of Japanese oysters among various bivalve larvae in the sea. This will help to determine the timing suitable to install seed oyster collectors in seawater, and promote to secure natural seed oysters for aquaculture efficiently.

The Great East Japan Earthquake caused major damage to the Japanese oyster farming industry in Miyagi Prefecture, so there is an urgent need to reconstruct this industry. Japanese oyster farming in the prefecture starts with the collection of seed oysters in the wild (seed collection); however, seed collection in Matsushima Bay, a major production area of seed oysters, was poor last year and two years ago, influencing not only the prefecture but also other parts of Japan that depend on seed oysters from the area.

To collect a large number of high-quality seed oysters, it is necessary to install seed collectors with accurate knowledge of the status of floating larvae. To enable stable and efficient collection of seed oysters in the wild, we have developed a simple technique for fishing operators to easily identify the floating larvae of the oysters.

By making only the floating larvae of Japanese oysters produce fluorescence using an antigen-antibody reaction, the larvae can be easily, accurately, and rapidly identified under a microscope.

This technique will allow the installation of seed collectors at an appropriate time and result in the efficient collection of seed oysters. Sufficient amount of seed oysters will contribute to the stable oyster production in prefectures affected by the disaster, as well as in other parts of the country.

The findings in this study were obtained via the Advanced Technologies Application Project for Revitalizing Food Production Areas based on the budgets of the Reconstruction Agency and the Agriculture, Forestry, and Fisheries Research Council Secretariat.

Fig.3 Identification of the floating larvae of Japanese oysters using a technique that we developed.

The larvae of only Japanese oysters are labelled by green light when illuminated with fluorescence, enabling them to be distinguished from other species. A, B: Larvae at different growth stages. C: Larvae from a wild community. (In all photos, left-hand images are from an optical microscope and right-hand ones are from a fluorescent microscope. The red lines represent 0.1 mm.)