Estimate growth and mortality parameters of Nematalosa nasus (Bloch, 1795) in coastal waters of the Persian Gulf (Hormozgan Province)

Abstract

Introduction: Some population parameters of N. nasus were studied by using Bottom-trawler
for a period of 18 months from Nov 2016 to Apr 2018 in the coastal waters of the Persian Gulf
(Hormozgan province).
Materials & Methods: A total of 618 fish were selected as bycatch from shrimp bottom trawl
and measured biometric data.
Results: The correlation between total length and weight for males and females showed a high
value (R2 were estimated at 0.71 and 0.72 for males and females, respectively. The b-value for
length-weight relationship was 2.58 and 2.69 for males and females, respectively, indicating a
positive allometric growth pattern in this species (P<0.05). The FL∞ was estimated at 172 mm
for males and 176 mm for females. In addition to the growth coefficient (K) for males and females
was estimated at 1.3 and 1.1 Y-1, respectively. Also, t0 for males and females were -0.07and
-0.08Y-1, respectively. The Φ` coefficient index in males and females were 4.59and4.53,
respectively. The recorded results of this study showed that the natural mortality rate (M) in males
was 1.28 Y-1and for females were 1.14 Y-1and the fishing mortality rate (F) was 3.25 in males
and 2.23 Y-1 in females, respectively
Conclusion: The total mortality (Z) for males and females was estimated at 4.53 and 3.37 Y-1,
respectively. Also, the exploitation coefficient (E) for this species was 0.66 and 0.72 in males
and females, respectively.