Nippon Suisan Gakkaishi 78 (4), 681-691 (2012)

Selectivity of experimental drift net for chub mackerel Scomber japonicus

AYAKO YANO,1 TADASHI TOKAI1 AND ATSUSHI KAWABATA2

1Tokyo University of Marine Science and Technology, Minato, Tokyo 108-8477, 2National Research Institute of Fisheries Science, Fisheries Research Agency of Japan, Yokohama, Kanagawa 236-8648, Japan

Fishery surveys of pelagic fish resources with experimental drift nets of 16 different mesh sizes were conducted in the waters off Sanriku and east of Hokkaido from 1984 to 2002. From the survey data, 37 data sets of fork length distributions of chub mackerel which were caught by drift nets of 12 different mesh sizes (26, 30, 33, 37, 43, 48, 55, 63, 72, 106, 112, and 121 mm) were used to estimate the master curve for expressing the size selectivity. The skew normal model was selected as the best-fitted selection curve by AIC. Girths at three positions (the center line of the eye, the posterior edge of the gill cover, and the anterior end of the first dorsal fin base) and maximum girth were measured with fork length. For the chub mackerel with the optimum fork length at the modal selection curve, the position of the girth equivalent to the mesh perimeter was within the range from the posterior edge of the gill cover to the anterior end of the dorsal fin base. This suggested that most of the chub mackerel were wedged or gilled by the mesh of the drift net.


  [BACK]  [TOP]