Age, Growth and Mortality Rate of the Narrow-Barred Spanish Mackerel (Scomberomerus commerson Lacepède, 1800) in Coastal Waters of Iran from Length Frequency Data
Abstract
Monthly data of length composition for narrow-barred Spanish mackerel, Scomberomorus commerson (Lacepède), landed between April 2003 to March 2005 along the Persian Gulf and Oman Sea were used to estimate the growth, mortality and exploitation parameters of the stock. Maximum fork length and weight were 132 cm and 18.4 kg respectively. Nonlinear least square fitting provided a complete set of von Bertalanffy growth estimates: L∞=140 cm fork length; K=0.42 and t0= -0.26 years. The estimated value of total mortality based on length converted catch curve using these growth parameters is Z=1.47 year-1. Natural mortality based on growth parameters and mean environmental temperature (T=26.5ºC) is M=0.49 year-1. Furthermore, the annual instantaneous fishing mortality rate of 0.98 year-1 was by far in excess of the precautionary target (Fopt=0.49 year-1) and limit (Flimit=0.65 year-1) biological reference points, indicating that the resource was heavily over-exploited, and that management of this species should have been implanted rapidly if they were to remain sustainable.
Age, Growth and Mortality Rate of the Narrow-Barred Spanish Mackerel (Scomberomerus commerson Lacepède, 1800) in Coastal Waters of Iran from Length Frequency Data
Abstract
Monthly data of length composition for narrow-barred Spanish mackerel, Scomberomorus commerson (Lacepède), landed between April 2003 to March 2005 along the Persian Gulf and Oman Sea were used to estimate the growth, mortality and exploitation parameters of the stock. Maximum fork length and weight were 132 cm and 18.4 kg respectively. Nonlinear least square fitting provided a complete set of von Bertalanffy growth estimates: L∞=140 cm fork length; K=0.42 and t0= -0.26 years. The estimated value of total mortality based on length converted catch curve using these growth parameters is Z=1.47 year-1. Natural mortality based on growth parameters and mean environmental temperature (T=26.5ºC) is M=0.49 year-1. Furthermore, the annual instantaneous fishing mortality rate of 0.98 year-1 was by far in excess of the precautionary target (Fopt=0.49 year-1) and limit (Flimit=0.65 year-1) biological reference points, indicating that the resource was heavily over-exploited, and that management of this species should have been implanted rapidly if they were to remain sustainable.
Details
| Primary Language | Turkish |
|---|---|
| Journal Section | Articles |
| Authors | |
| Publication Date | April 1, 2007 |
| Published in Issue | Year 2007 Volume: 7 Issue: 2 |