カジカCottus pollux GUNTHERの生態的2型

概要

論文の詳細を見る
The common freshwater scorpion, Cottus pollux Gunther, was divided into two ecological types, the large-egg and small-egg type. The large-egg type spawnsa small number of large eggs in winter (Fig.1; Tables 1 and 2). Soon after the absorption of yolk, the larvae transform directly into the benthic young fish ofthe essential form of adult. They spend their whole life in the upper course ofrivers (Figs.3 and 4). The small-egg type spawns in winter a great number of small eggs (Fig.1; Tables 1 and 2), from which swimming larvae hatch out (Fig.5). Their early larval stages are spent in the stagnant waters like seas and lakes. In spring they ascend the rivers, and stay in its middle and lower courses (Figs.3 and 4). These two types are distinguished in the number of pectoral fin rays(Table 3 and Fig.4). Comparing the life histories of freshwater scorpions in Japan, it was concluded that the large-egg type of Cottus pollux might have been derived from the small-egg type of the same species.
社団法人日本動物学会の論文
1961-08-15