علوم زیستی دریا
Emad Koochaknejad; Ahamd Savari; Alireza Safahieh; Gholamreza Eskandari
Abstract
In this study age, growth and maturity of Hilsa shad in Khuzestan province were analyzed. 394 number of fishes from marine habitat (Life-Boseif), estuaries (Bahmanshir and Arvand) and rivers (Bahmanshir and Karoon) from February 2014 to September 2014 were collected using commercial fishing with gill ...
Read More
In this study age, growth and maturity of Hilsa shad in Khuzestan province were analyzed. 394 number of fishes from marine habitat (Life-Boseif), estuaries (Bahmanshir and Arvand) and rivers (Bahmanshir and Karoon) from February 2014 to September 2014 were collected using commercial fishing with gill net. Total length and wet weight of each fish were measured with precision of 1 cm and 1 gram. Sagittal otoliths were extracted for age determination of the fish. Then abdominal cavity of each sample were opened for determining sex and maturity stage. Growth parameters were calculated using von Bertalanffy growth function (L∞=58.365, K=0.26, t0=-0.16). Phi-prime constant was obtained 2.95. Length and age at first maturity were obtained 27.32cm and 2.4 g respectively using logistic model to fit a and b parameters with observed data in spawning season.
علوم زیستی دریا
gh s; Emad Koochaknejad; Yosef Mayahi; Houshang Ansari
Abstract
The main goal of this study was estimating discards of trawl nets in north western part of the Persian Gulf. Data were collected from fishing boats in fishing areas of Lifeh, Boseif, Khure-mussa and Bahrakan from October 2011 to September 2012 with collaboration of fishery office. Discard samples include ...
Read More
The main goal of this study was estimating discards of trawl nets in north western part of the Persian Gulf. Data were collected from fishing boats in fishing areas of Lifeh, Boseif, Khure-mussa and Bahrakan from October 2011 to September 2012 with collaboration of fishery office. Discard samples include 101 species from 61 families which are 39.5% of commercial catch and 60.4% of non-commercial catches. Rayfish and catfish have been observed in most fishing nets. The average size of bony fishes in discard samples was lower than 15 cm. Total weights of discards was estimated about 1109 tons per year. Total weight of commercial fishes with small size in discards was estimated 2736 tones. The rate and proportion of discards in total catch of trawl was estimated 0.5 and 1.03 respectively. Osteichthyes with 70 species and 50.7% of trawl catch has the highest percentage of discards in trawl nets. High rate of small fishes in commercially important species of discards is probably due to nursery role of Khuzestan coastal waters.