Relationship between tidal range and catch of pound net in Kasaoka Bay

　内湾に設置された桝網について，その漁獲量と環境要因との関係を明らかにするために， 1957 年7月から12月迄の6カ月間，笠岡湾の引野水域で操業された数統の桝網の1i統当りの目別漁獲量と漁場の潮差との相関々係について統計的な解析を試みた結果，両者の間には可成り高い正の相関が認められた.即ち，月別ではその相関係数は7月1<: 最高の0.835 を， 11 月に最低の0.453 を， 6ヵ月間の合計では0.468 を示し，何れも統計学的に有意であった.又，両者聞には直線関係が認められ， その回帰係数は1.40 (kg/m) で，潮差が桝網の漁獲量IL 可成り大きく影響することが判明した.

1) Relationship between the tidal range of the fishing ground and the daily catch per unit masu-ami (a kind of pound net) was discussed by statistically analyzing the data obtained from the several regular masu-ami of the commerical catch operated at Hikino water area of Kasaoka Bay, located along the northern middle part of the Seto Inland Sea, during six months from July to Dec. in 1957.
2) The abundance of the daily catch per unit masu-ami had a highly significant correlation with the tidal range of the fishing ground as the result of calculating the correlation coefficient between the two in each month.
3) In masu-ami fishing, although the catch per unit masu-ami fluctuated by fishing season, there was a linear relation between the tidal ranges and the mean daily catches per unit masu-ami against the corresponding tidal ranges, moreover, the regression coefficient amounted as much as 1.40 (kg/m) throughout the fishing season in 1957.