"A trend of the otter trawl net fishery in Ise Bay [Japan], 2: Stock assessment of ma-anago [Conger myriaster] in the southern fishing ground of Ise Bay."
1986
"Nakajima, H. (Mie-ken. Government Office, Tsu (Japan))."
"Though ma-anago is the most important of all fishes caught by the otter trawl net fishery in Ise Bay, we cannot obtain its annual catches in Mie Prefecture. Fortunately, Aritaki fishermen's association began to make out the data of daily catches classified by species in the otter trawl net fishery from 1984. Then, an attempt was made to estimate the stock and the rate of exploitation of ma-anago, using the data on the fishery in 1984 and 1985. On the other hand, according to the previous acknowledgements about ma-anago in Ise Bay, it was considered that ma-anago population was mainly consisted of 1 and 2 aged fish and the 2 aged fish migrated toward the mouth of Ise Bay. The migration of ma-anago abve mentioned was also recognized from April to July with the sampling investigation of the otter trawl net fishery in Aritaki in 1984. The present study is the first approach toward the assessment of ma-anago stock with the catch and effort statistics in 5-day period. The CPUE (number/boat-day) was decreased gradually from April to August. The tendency in CPUE in 1985 was also similar to that in 1984. As the decline of CPUE was considered to be mainly due to the capture, DeLury's equation was applied for estimating the catchability coefficient. Consequently, it was estimated to be 7.604 * 10E-4 in 1984 and 7.884 * 10E-4 in 1985. The initial stock of ma-anago and the rate of exploitation were estimated to be 339 * 10E4, 65.7% respectively in 1984 and 342 * 10E4, 58.8 % respectively in 1985. Judging from the analysis for two years, annual recruitments of the population scarcely fluctuate in the southern fishing ground of Ise Bay."
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