サケ・マス流網に羅網する漁獲物の個体重量の分布について-II

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書誌事項

タイトル別名
  • ON THE WEIGHT DISTRIBUTION OF THE FISHES CAUGHT BY DRIFT NETS IN THE REGION OF THE NORTHERN PACIFIC OCEAN-II
  • サケ マス ナガシアミ ニ ラモウ スル ギョカクブツ ノ コタイ ジュウリョウ ノ ブンプ ニ ツイテ 1 2
  • THE WEIGHT DISTRIBUTION OF INDIVIDUAL FISH IN THE REGION OF THE NORTHERN PACIFIC OCEAN.
  • 北洋流網漁場で漁獲されるサケ・マスの個体重量分布

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説明

If we will assume that the results of the previous paper concerning the weight distribution of the individual fish caught by gill nets are applicable in the case of the salmon driftnets used in the region of the Northern Pacific Ocean, then it may be considered that the number of the fish caught by the drift nets (n), which have the weight (w), is proportional to the formula exp [-k1(w-h2owo+h2iwi/h2o+h2i)2]. Consequently, the mean number of the fish caught by per unit of drift nets is proportional to the formula of the exp [-k2(wo-wi)2].<br> In this paper, from the underlying treatment we get the value of wo with the aid of the value (h2o+h2i) and (h2owo+h2iwi) computed from the data in the ocean field. The individual weight of the fish caught is measured under the consideration of the following different condition: the difference of size of mesh (12.1, 12.4, 12.7, 13.3cm), the difference of species of fish [red salmon (Oncorhynchus nerka (WALBAUM), chum salmon (Oncorhynchus keta(WALBAUM), pink salmon (Oncorhynchus gorbuscha (WALBAUM)), silver salmon (Oncorhychus kisutch (WALBAUM))], the difference of the portion of fish body which is gilled in the mesh used (operculum (II), middle portion of operculum and dorsal fin (III)). Refering to the above result, the values of (h2o+h2i) and (h2owo+h2iwi) were obtained by the same treatment as the previous paper. Consequently, it was estimated that these values do not so depend on the size of mesh (li) (Table 1, Fig. 1, Fig.3).<br> Accordingly, h20w0+h2iwi may be transformed into the following formula h2owo+h2iwi=[h2o+h2i(li/lo)3]wo (lo: shows the mesh size which is most easily to catch fish in the fishing field and value of lo is alike to the commercial mesh size 12.1-12.4cm). Where li/l0 ?? 12.1/13.3 then (li/l0)3 ?? 0.75 and h2i<h2o (refer to the previous report). Therefore, wo may be obtained from the known values of h2o+h2i and h20wo+h2iwi (Table 2).<br> The mean number of the fish (per unit of drift nets) which are gilled in the mesh in a certain portion of fish body, namely Ni, may be evaluated by the following expression: Ni∝exp [-h2oh2i/h2o+h2i(wo-wi)2]. Accordingly, Ni has a max. value in the case wo=wi. Therefore, we evaluate the value of li given the max.

収録刊行物

  • 日本水産学会誌

    日本水産学会誌 27 (5), 377-381, 1961

    公益社団法人 日本水産学会

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