علوم زیستی دریا
Khatereh Mehrabani; Mohammad Khosravizadeh; Vahid Yavari; Seyed Mehdi Hosseini; Omid Beyraghdar Kashkooli
Abstract
The aim of this study was to estimate the amount and species composition of discards in bottom trawl fisheries in the Bosif fishing ground in the coastal waters of Khuzestan. Furthermore, the biological parameters of discarded species were assessed. Specimens were collected from commercial catch data ...
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The aim of this study was to estimate the amount and species composition of discards in bottom trawl fisheries in the Bosif fishing ground in the coastal waters of Khuzestan. Furthermore, the biological parameters of discarded species were assessed. Specimens were collected from commercial catch data of trawl vessels in three seasons, autumn and winter 2017 and summer 2018. The results showed that discarded samples included 33 species from 28 families. Orangefin Pony fish and striped piggy species were the most frequent species in this study. The results also showed that the mean length of most of the discards species was below 30 centimeters. The amount of discards per unit of catching effort was 57.33±9.87, 27.50±16.64 and 32.33±7.50 in the autumn, winter and summer seasons, respectively. The catch per surface area in autumn, winter and summer were 2.77 ± 0.064, 0. 73 ±0.39 and 1.73 ± 0.44 kg/nm2, respectively. The results showed that CPUE and CPUA in winter were significantly higher than those in autumn and summer (p<0.05). In general, the results of this study represent high fishing pressure on ecologically important species in Bosif fishing ground especially in their critical life cycle which may affect local ecosystem structure and function in future.
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 ...
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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.