Comparative biological characteristics of Electrona carlsbergi (Tåning) (Myctophidae) from the notal and Antarctic areas in the Southern Ocean Atlantic sector

Some biological peculiarities of E. carlsbergi from the Antarctic and notal areas of the Southern Ocean Atlantic sector have been studied on the basis of the data for 1987-1989. Mean length of fish from the Antarctic area increased while drifting eastward in the Antarctic circumpolar current waters. Fish specimens from 62 to 97 mm long were registered in catches. About 95% of specimens analysed were at age 2 to the west of 35°W and 3 yr old specimens , the portion of which made up to 40% in catches, occurred in much high amount to the east of 30°W. In the notal area the length of E. carlsbergi reached 103 mm. Fish from older age groups (3 and 4 yr old) constituted about 85% of total amount, with fish at age 1+ (to 75%) being noted in separate catches. Essential distinctions in a nature of the "fish length/fish weight” and "fish length/otolith weight" relationships between males and females from the Antarctic and notal areas have been elucidated. Growth rate in the notal area was somewhat higher,with the highest increment being observed at the 1st and 2nd years of life. Limiting age for fish from the notal area is, probably, 5 years. E. carlsbergi investigated in the Antarctic waters occurred to be immature. Spawning was registered in summer only in the notal area.Over 50% of specimens become mature at the 3rd year of life at 85-89 mm length. Determined differences of the length–age and length–weight compositions, as well as the rate of growth and maturation in comparable groupings indicate a possible expatriation of E. carlsbergi to the Antarctic area from the region of reproduction of the notal one.