Premium
Diel feeding periodicity, daily ration and vertical migration of juvenile Cape hake off the west coast of South Africa
Author(s) -
Pillar S. C.,
Barange M.
Publication year - 1995
Publication title -
journal of fish biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.672
H-Index - 115
eISSN - 1095-8649
pISSN - 0022-1112
DOI - 10.1111/j.1095-8649.1995.tb06000.x
Subject(s) - diel vertical migration , cape , biology , juvenile , fishery , west coast , cove , oceanography , ecology , geography , geology , archaeology
Feeding periodicity, daily ration and vertical migration of juvenile Cape hake Merluccius capensis are investigated from midwater and bottom trawl collections taken during a 42‐h period between 29 February and 2 March 1992 at a fixed position off the west coast of South Africa. Feeding of 10‐20 cm hake intensified during the night when they ascended into subsurface layers to prey on recruits of anchovy Engraulis capensis. Larger hake remained close to the bottom, were partially cannibalistic and exhibited no diel feeding periodicity. M. capensis appear to migrate vertically and feed asynchronously in midwater, as individuals, and not as a population, returning to the bottom when satiated. Based upon the exponential rate of decline in stomach fullness throughout the day, the evacuation rate by hake <20 cm was estimated as 0.054 h −1 ; 90% evacuation of anchovy prey required an estimated 43 h. Using the Elliott & Persson and Eggers methods, the daily ration was estimated as 5.51 and 4.15% of wet body weight respectively. The effect of the foraging behaviour of M. capensis on the appropriateness of acoustic sampling for estimates of their abundance is discussed.