カレイ類の棲息場所選択と環境の評価についての実験的研究
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概要
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The indiuidual fish of Limanda yokohamae was liberated one by one from a definite position into the experimental pool, whose bottom was provided on one side with the fine sand and the other side with the small gravel, each in half space. The number of individuals settled on either the sand or the gravel bottom was counted at each time of the liberation. The same was done by the different species, Kareius bicoloratus. The results showed that, when the population density is low, both the species tend to settle on the side of sand than gravel; however, with the increasing density, the tendency of preference for the sand gradually falls. (Figure 1) Namely, the probabilities for the settlement on the sand are high at the lower density and decrease as the density becomes higher. In order to find out the relationship between the habitat preference and the population density, MORISITAS theory on the environmental density and probability formula derived from its theory were applied for the analysis of the results of this experiment. The frequency distribution of the number of individuals settled on the bottom of the tank were conicident well with the expected values calculated by MORISITAS formula for both the species (Tables 2 & 3). The values of the environmental density (expressed as the population density) were 0.10 for the sand and 3.10 for the gravel in the case of L. yokohamae and 0.22 for the sand and 1.95 for the gravel in the case of K. bicoloratus.
- 公益社団法人 日本水産学会の論文