GROWTH, MORTALITY AND RELATIVE YIELD PER RECRUIT OF TWO TRIGLID SPECIES FROM THE EGYPTIAN MEDITERRANEA1V, OFFALEXANDRIA.

GROWTH, MORTALITY AND RELATIVE YIELD PER RECRUIT

OF TWO TRIGLID SPECIES FROM THE EGYPTIAN

MEDITERRANEA1V, OFFALEXANDRIA.

By
S.N. FALTAS* AND M. A.B.DALLAH
*Nationallnstitute ofOceanography and Fisheries. Alexandria, EGYPT
Key-words: Familj’ Triglidae. Fisheries biology, Alexandria, -Mediterranean.
ABSTRACT
Trigla lucerna Linnaeus, 1758 and Trigloporus lastoviztl
(Brunich, 1768) are the most commercially important species of
triglids in the Egyptian Mediterranean waters offAlexandria. Growth:
mortality, relative yield per recruit and related parameters ofthese
two species in the trawling catch were estimated from length~
frequency data using compleat ELEFAN sojrM.lare. The estimated von
Bertalanffy growth parameters were Lro = 40.3cm & K= 0.287 year-I
for T. lucerna and L ro = 34.7 cm & K = 0.372 year-1for T. ltzstoviza.
Natural mortality, fishing mortality and exploitation ratio were 0.66,
0.83 year-1 & 0.56 for T. lucerna and the corresponding ones were
0.81, 2.01 year-.l & 0.71 for T. lastoviza. It is found that T. lastoviza
is overexploited. Therefore management should be recommendedfor
its fishery.