Figure 3 shows the frequency distribution of 0~6 ; out of 21 examples 

 62^ are within the range of +1° - + 2°, and 2.6% are within the range of 

 +2° - +3°, values of + 1°- +3° thus occupying 88% of the total, while 

 values of 0°- +1° are only 7% and those of f 3°-+4.° are only 5^c Judging 

 from these data^, the body temperature of the skipjack rises with the water 

 temperature, and always shows a difference of about +2*^ from its environ- 

 raento Considered in more detail, a tendency could be perceived for this 

 temperature differential to show greater values at lower body temperatures 

 or lower water temperatureSo As for differences in body temperature de- 

 pending on the size of the fish, the data for May, 19^0, show higher @ 

 for the smaller fish, but this is not clear for the earlier data^ The 

 idea that within the range of water temperatures which can be considered 

 the so-called "suitable temperatures" the skipjack regulates its body 

 temperature with respect to the surrounding water temperature proceeds 

 naturally from the relationships of (l), (2), and (3) cited above„ At 

 the same time the fact that the body temperature of the fish is always 

 higher than the water temperature means that heat is constantly being 

 taken off into the sea water from the surface of the body of the fish,, 

 3hfifact that it is constant shows that, the heat energy^l) liberated being 

 supplied within the body by the food taken in, this supply is almost 

 constant. The amount of heat energy released from the whole body of a 

 2 kg fish is about 3,500 gr.cal„, and where the water temperature or the 

 body temperature is high, the amount is small, but where the water tempera- 

 ture or the body temperature is low the amount becomes comparatively great. 



There are records of body temperatures taken on the catch from 

 experimental tuna longline fishing by the research vessel Shonan Maru of 

 the fisheries experiment station of the Taiwan Government-Generalo ^^' 

 When these are shown graphicallyy as was done in the case of the skipjack, 

 the results are as shown in Figure 5 a, b, c, and d„ For the yellowfin 

 tuna at water temperatirres of 25° - 27 the body temperature can be 

 shown by the approximate formula Qslol - lo3, 9 being 1,2° = 1„A°C 

 higher than „ For the true marlin /~Tet-rapturus mitsukurii 7 at 

 temperatures of 2^^ = 27°C5, ® s 0,8 +6„X and @ is 0,7° = 1.3° 

 (average l^C) higher than , In the case of the big-eyed tuna at 

 023° = 26*^, s 0„7 +8„A and ® is 0.6° = 1„5° (average 1°C) higher 

 than 00 For white-^tioped shark / Carcharinus albimarginatus 7 at 6 25° - 

 23°C, g) s Oo9 0+3o2 and @ is about 0o6° higher than „ For the dolphin 

 at 025° = 28°C, = 0o94. +2ol and @ is about 0„6° higher than . 

 Thus not only the skipjack;, but also the tunas have body temperatures 

 0o5° •= lo5° higher than the water temperature, and the white-tipped shark 



^1) Hoshino, Saburo:" On the Specific Heat of Fish Fleshy Journal of the 

 Japanese Refrigeration Society, Volo5j No, 51, March 1930o According to 

 this article the specific heat of fresh skipjack flesh is 0o882„ Assuming 

 that the specific heat of the live fish is of this order, for a difference 

 of 2 C between water temperature and body temperature the amount of heat 

 released from the whole body of a 2 kg skipjack would be 2000 X 2 X 0^582 

 a 3523 groCala 



(2) Taiwan Government-General Fisheries Experiment Station, Experimental 



Tuna Longlining in the Tfeters East of Formosa in 1936 (published in 1937), 

 pp„ 22-66„ 



19 



