Nippon Suisan Gakkaishi 73 (3), 487-494 (2007)

Growth of the snow crab Chionoecetes opilio estimated by carapace width frequency analysis in the waters off the Pacific coast of northern Honshu, Japan

YUJI UEDA,1* MASAKI ITO,1 TSUTOMU HATTORI,1 YOJI NARIMATSU,1 KUNIHIRO FUJIWARA,1a TETSUYA YOSHIDA2 AND DAIJI KITAGAWA3

1Hachinohe Station, Tohoku National Fisheries Research Institute, Fisheries Research Agency, Hachinohe, Aomori 031-0841, 2Fukushima Prefectural Fisheries Experimental Station, Iwaki, Fukushima 970-0316, 3Hokkaido National Fisheries Research Institute, Fisheries Research Agency, Kushiro, Hokkaido 085-0802, Japan

Growth of the snow crab Chionoecetes opilio in the waters off the Pacific coast of northern Honshu (PNH), Japan was investigated using carapace width (CW) frequency analysis. The CW frequency of this stock in 2001-2005 was separated into six instars with 27-93 mm of mean CW for males, five instars with 30-77 mm of mean CW for females. Mean CW of each instar of females was slightly different from that of males. Almost all male and female crabs attained terminal molt at 110 mm and 76 mm CW, respectively. Mean CW of each instar and proportion of numbers of terminal molted male crabs were compared to previous studies in the Sea of Japan. While mean CW of each instar in PNH was similar to that in the Sea of Japan, the proportion of numbers of terminal molted male crabs in PNH was higher than that in the Sea of Japan for each CW class. One of the reasons why few large male snow crabs are found in PNH was that the size at terminal molt was different between PNH and the Sea of Japan.


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