COMPARAXrVE STUDY OF SCOMBROID FISHES. 44^ 



with IV k1 aud line late iu summer. Sudi iminntnre fish are called " imosliiln " 

 in Miyazaki-kcn. Still smaller fish are called " kakinotaue " iu Ivaiiaf^awa- 

 keu, and "abiikj" or " bints ;i " iu Mije-keu. These immature fishes are 

 fmnd in assiwiatiou witli Aitxis, feeding chiefly on peliigic cn'usta(«aas. These 

 immature fish gi-ow to a length of ca. 40 cm, weighiug ca. 1 kg in wiuter, 

 and in the next summer 2-3 kg in veiglit. 



In summer, June and July, the reproductive glands ai*e very large, and 

 the fi.sh swarm uejir the snrfiwe of the water, <jften siiowing their dorsal fins 

 out of water. This is the case in the northern parts of our waters, Iwth on 

 the Pacific jind Japan Sea coasts. These raatm-e fishes are iissociated with 

 iimnaturo fishes. I have, however, not yet examined a tunny with fully ripe 

 reproductive elements, and in August tlie reproductive glands are found spent. So 

 that we are inclined to l)elieve that the tunny spawn in of&hore watere. OlTthe 

 southern part of Kyushyu aud also ofi" the Pacific coast of the centi'al part 

 of Hondo, we find small immatm'e tiuniies in summer and autumn. In these 

 watei-s the common tunny with ri]^ie reproductive glands is not known. But 

 it is difficult to l)elieve tliat those immatm'e fishes migrated fi-om the nortliei-n 

 waters. 



Timoies are cjiught more uii dark nights, and Ijefore a storm. When tlie 

 weather is warm witii a southerly wind, tunnies come near the surface of 

 the water, and a good catch by drift-nets is expected. On a dixy of northerly 

 wind drifters do not go out fisliiug. Tliey are said to swm against the 

 (Min'ent, espacially when they are near the coast, hence they enter l)ays or 

 inlets iu low tide and seek ofi'-shore groimds iu high tide. Tunnies dislike 

 a water of a low density-, so that they do not approach the coast on a rainy 

 <Uy, nor approach the mouth of a river. They are found in a water of ca. 

 1.024-1.025 in deusity. 



It is said tliat when a shoal of timnies is frightened at sometliing ahead 

 of them, every tunny of the shoal turns back immediately just at the spot 

 where it happens to I)e. Tlius tlie liindermost fish lead the schrxjl when 

 i-etiring. In 1921 a few immjitm« tunnies were caught off Sendai in set-nets, 

 at a depth of ca. 300 m. Tlie nets were for a kind of deej>-sea shai'ks. These 

 titunies were prolmbly entangled, wliile tlie net was Ijeing hauled in, or when 

 letting it out in the sea. 



