NAOSITE: Nagasaki University's Ac Title 南太平洋におけるマグロ類とマカジキの体長と体重の関係について Author(s) 古賀, 重行 Citation 長崎大学水産学部研究報告, v.21, pp.23-31; 1966 Issue Date 1966-11 URL http://hdl.handle.net/10069/31460 Right This document is downloaded http://naosite.lb.nagasaki-u.ac.jp
23 The Relationships between Length and Weight of Tunas and Striped marlin in the South Pacific Ocean Shigeyuki KOGA* The data were obtained by the Koyo tuna fishing fleet in the Fiji area during the period of four months from August to November, 1958. At present the Fiji ground is restricted roughly to the area extending from 170 E. to 170 W. and from 18 S. to 30 S. The purpose of this report is to estimate the conversion equation between length and weight of albacore, Thunnus alalunga (BONNATERRE) and striped marlin, Makaira audax (PHILIPPI), caught in the Pacific Ocean. Therefore, for converting length-frequency data to weight-frequency data, the length-weight relationships derived from the regression of weight on length can be taken as: albacore ; w = 2. 257.l - 3. 198 striped-marlin ; w = 3. 504.l - 6. 737 where 1 is logarithm of length (cm) and w is logarithm of weight ((1) in kg, (2) in kan). The relationships are illustrated in Figs. 1-3 and Table 1. The bodyweight of those with the same body-length differed by locations. The body-weight of albacore and yellowf in tuna caught in the area to the north of the equator showed a trend to increase as the fishing ground proceeded eastward. while, in the area to the south of the equator, yellowfin tuna and bigeye tuna from the intermediate latitude are mostly of body-weight than those from the low latitude. The body-weight of albacore in the Fiji area (18-30 S) is generally larger than that in the North-Western Pacific Ocean. The body-weight composition of albacore distributed in a location south of the equator is exactly identical with that on the same latitude north of the equator. In the South Pacific Ocean, the catch of the striped-marlin consists of large sized ones. The principal group is composed of mature fishes with the body-weight from 55 to 111 kg. But on the contrary fishes with the body-weight from 23 to 36 kg are the leading group in the North-Western Pacific Ocean. (Shimonoseki University of Fisheries).
24 In the area north of the equator, the length-weight relationship of bigeye tuna scarcely varied according to the location and season Therefore, for the purpose of converting length frequency samples to weight frequency samples, it seems that the statistics obtained from the total regressions are not affected by the difference in location or seaons
2) CUATWIN, B M The relationships between length and weight of yellowf in tuna (Neothunnus macropterus) and skipiack (Katsuwonus pelamzs) from the Eastern Tropical Pacific Ocean Inter-American Tropical Tuna Comm, Bull, 3 (7), 304-343 (1959) 4) IVERSEN, E S Size frequencies and growth of central and western pacific bigeye tuna U S Fish and Wildlife Sery, Fish Bull, (162), 1-40 (1955)