COMPARATIVE STtTJT OF SCOMBKOID FLSFIES. 40Ü 



siiba. MoTOover in the former variety tbo dark coloured bauds iu the back ruu 

 down beyond the lateral meditin lint". Tii that variety the caudal fin Ls yellowish. 

 The fish lives near tlie coast, but iu deejier layers of water. Its flesh is more 

 oily and pilatable. Iu the other variety which is also called " gomasaba " tlio 

 dark coloured bands in the back are found, only alx)ve the lateral median lino. 

 On that lino there is a row of round s])ois, and below the line there are 

 numerous greyish spots. It is chiefly found in off-shore gi-ounds and in shallower 

 strata of water, makiug larger shoals than the former variet}'. 



This species inhabits rather littoral waters, and its range of distribution 

 in our country is very wide, from Karafuto to Taiwan. On our coast this 

 species is rarely found in layers of water deeper than a1x)ut a hundred metres. 

 We observe more or less the bathybial as well as Lititudinal migration of the 

 mackerel. In spring the mackerel enters the Inland Sea, and in summer it is 

 caught off Notasan, west coast of Karafuto. In whiter it is caught near Ta- 

 n^jushima, Kagoshima-kou. In Houdo it is caught all the year roimd, but 

 large catches are eiq^ectod in summer and autumu. It is also caught abim- 

 dantly on the east coast of Chosen, especially near the Channel of Chosen. At 

 the Channel of Chosen, i. e. at the southern entrance of the Japan Sea, ma- 

 ckerels make thick shoaLs in spring and autumn. Two hundred and sixty thou- 

 sand mackerel with a part of saurel were caught iu a haul with a purse seine. 

 Sometimes two milhons of mackerel are Lmded in the jwrt of Hügj-oshin near 

 Fusan in one day. IMackerel are caught in twilight when they come to shal- 

 lower layers of water. In cloudy weather they often rise to the siurface. 



Adult mackerel appi'oach the twenty metro liue shoreward, and are dis- 

 tributed a little beyond the two hundred metre line. They are never found 

 in the Kuroshiwo, being found in waters of 10-20° C. On a cold day and during 

 the cold season mackerel are found near the bottom of the sea. The optimum 

 density for the mackerel is 1.025. 



Mackerel spawn in May. Fry and the immatiu-e fish are found among those 

 of the sardine, anchovy, and the saurel. Thej- grow very rapidly, feeding on 

 fries of other fishes. When they are about 36 cm iu length and i kg in weight, 

 they are riyie for the first time. The age of these fishes is not exactly known. 

 They may be two or three years old. Fish of about 60 cm long and li kg 

 in weight are very large and rare. 



