RESOURCE ASSESSMENTAND MANAGEMENT PROSPECTIVE OF TWO NEMIPTERlD SPECIES (NEMIPTERUS JAPONICUS AND N. ZYSRON) IN THE GULF OF SUEZ

RESOURCE ASSESSMENTAND MANAGEMENT PROSPECTIVE OF

TWO NEMIPTERlD SPECIES (NEMIPTERUS JAPONICUS

AND N. ZYSRON) IN THE GULF OF SUEZ

BY

AZZA A. EL-GANAINYAND SAHAR F. MEHA.NA

National Institute OjOceanographyAnd Fisheries. Suez Branch,PD. Box 182, Suez, Egypt.

E-lvfail: [email protected]

Keywords: Nemipterus japonicus; Nemipterus zysron; Relative abundance; Grmvth;
Mortality rates; Exploitation; Yield per recruit.
ABSTRACT
The population parameters of’t’tvo commercially important nemipterid
species (Nemipterus japonicus and Nemipterus zysron) were estimated
from length frequency composition. Samples were collected from the Gulf
of Suez during the jishing season 2000/2001. The von Bertalanffy growth
fimction (VBGF) estimates were: L~= 28.35 em. total length, K= 0.63
year-l and to = -0.435 years for N japonicus. The corresponding estimates
for 1,. zysron were Lco=28.1 cm, K=0.58 yr-l
, and to= -0.475 year. The total
mortality coefficient (Z) was computed as 3.18 yrl
, the natural mortality
coefficient (M) estimated as 0.967 yrl with fishing mortality calculated as
F= 2.213 yr-l and the exploitation ratio (E==F/Z) for N japonicus was
0.696. The mortality estimates for N zysron were Z= 2.33 yr-1
, M= 0.946
yr-l and F= 1.384 yr-l and exploitation ratio (E) calculated as 0.594. The
Beverton and Holt yield per recruit model was used to explain the present
status ofthe nemipteridjishery, which shows that N japonicus stock in the
GulfofSuez is overexploited.