Premium
Age, growth and natural mortality rates of some cichlid fishes of Lake Malawi
Author(s) -
Tweddle D.,
Turner J. L.
Publication year - 1977
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.1095-8649.1977.tb04070.x
Subject(s) - fecundity , biology , cichlid , seasonal breeder , maturity (psychological) , fish <actinopterygii> , ecology , fishery , zoology , population , demography , psychology , developmental psychology , sociology
The growth rates, lengths at maturity, fecundity and natural mortality of several cichlids of importance in trawl catches in Lake Malawi are described. Growth rates were determined by analysis of length frequency data from trawl catches. The breeding season for each species was determined by monthly examination of the gonads, and fecundity determined by egg counts from ripe ovaries. Lengths at maturity were calculated from the proportion of mature fish during breeding seasons. Natural mortality rates were determined from length frequency data from an unfished area of the lake. Values of the growth constant K ranged from 0.487 to 0.671. The ratio of length at maturity to asymptotic length varied from 0.56 to 0.82. Growth parameters are compared with those of other cichlids. Most species mature in their third year. Fecundity was proportional to the square of the length in four of the five species. The species studied appeared to produce only one batch of eggs per breeding season. Instantaneous natural mortality rates ranged from 0.92 to 1.69.