野生メダ力保護ヘの提言

摘要

The wild populations of Medaka, Oryzias latipes complex now are facing to extinction by human activities, because they occur in such closed habitats as aquatic environment where various negative factors bring about direct influence. Among them, the release of a commercial variant "Himedaka" to nature is one of the most dangerous actions to induce the genetic contamination through hybridization with the wild populations. The basic idea to protect the wild populations of Medaka is provided by substantial approach viz., "In situ Conservation" and "Ex situ Preservation" . “In situ Conservation" literally means to protect the whole population without any changes in natural environment such as fish sanctuary as Nakaikemi wetland where they actually occur in original distribution. "Ex situ Preservation" aims to keep each threatened population as stock or gene-bank by gathering some individuals from natural environment to artificial equipment. “In situ Conservation" and “Ex situ Preservation" as well as "Enlightenment to public" are needed, and three must be coordinated as parts of unified programs as far as "Protection" for the wild Medaka populations is concerned. To avoid the confusion between wild and domesticated Medakas for classification, new terminology for domesticated Medaka is proposed, with subdivided into "Laboratory Medaka" and "Aquarium Medaka". Nomenclature by Latin name on both wild and domesticated Medakas are discussed as well according to the latest taxonomic information.