COilPARAinE STfOY OF SrOMBEOID FLSRE-S. 389 



vei"tebml columu, it c;iu not lie en3Ll\' In'ut. Tho tail-Cm is rigid ;i,uil liiuiite, 

 its quick and ^wwerM strokes cjiii Ijo uudersti:iil from the quick iind IJgli 

 pitched souud pitKluced liy the fish in its death-struggle on the deck of a boat 

 when caught. If a hmding hook is driven by uiisfcike into tlic caudal peduncle of 

 a tunny, we can not hold it, as the hands Ixx-oiue paralyzed h^om the violent 

 convulsion of the muscles. Neither can we hold, even for a few seconds, a 

 landing hook driven accidentally into a tunny swimming away from our lx)at. 

 Reallj- bonitos and tunnies swim like meteoi's. The ti"olI-line for tunnies as 

 ^^ell as the line attached to a harpoon-head used in timuy-fisliing require a 

 ivsen-e of at lejist 200 m, though the ti'oU-lino for a seorfish luis a reserve of 

 only 30 m or often none at alh 



mCRATION. 



The scombroid fishes, especially the plecosteans are good swimmers, and as 

 they are voracious, they are forced to swim .alwut incessantly in search of 

 food. Like many other fishes, scombroid fishes generally swim in shallower 

 strata of water at night, and seek the deeper strata in day-time. They migi'ate 

 more or less accorcling to the change of temperatiu'e. lu the cold season 

 they seek lower latitude.?, iu summer they go fui-ther north ; but Gyhiwiii 

 commosmi seems to be exceptional, visiting the western coast of Hondo in 

 the Japan Sea in ^vinter only. The migration of the striped l»nito is also 

 i-emarkable. On the Pacific coast the fish migrate with the wai'm current and 

 in summer they reach the southeastern coast of Hokkaido and remain tl:ere 

 till autumn. Iu their northerh' migration they apx^roach the coast, but iu 

 moving south tliey swim off-shore. In the Japan Sea they take a quite 

 difiei'ent com'se, appnxiching the coast in their southerly migration in the cold 

 season. The migi-atiou of Thunnns orienkdis and Tk. gernio in the Pacific 

 coast is nearl}- the same as that of the stri^ied bouito. Thunnus orieiitalis in 

 the Japan Sea approaches the coast in going north, in early summer. 



Generally s^x^akiug of scombroid fishes, large and old are caught at the 

 beginning of the fishing season, wliile at the end of the season only yomig 

 and small ones aie found. 



