Destructive effects of small-scale shrimp trawl fisheries on by-catch fish assemblage in Hormozgan coastal waters

The aim of present study was to determine by-catch composition and contribution of non-standard fish in small-scale shrimp trawl fisheries in Hormozgan coastal waters. Sampling was performed in 2012 shrimp fishing season by 3 small-scale vessels. At the end of 38 hauls، the samples contained 82 species: 53 teleost taxa contributing 71. 8% of the total biomass، 6 elasmobranchs taxa (15. 5% of biomass) and 6 species of invertebrates (12. 7% of biomass). Also contribution of teleost، elasmobranch and invertebrate species was 85. 5%، 0. 48% and 14. 02% from total catch numerically. Small discard species، large discard fishes، commercial species and shrimp consisted 45. 17% (59. 34% of total catch number)، 27. 84% (1. 16% of total catch number)، 14. 5% (2. 53% of total catch number) and 12. 49% (36. 97% of total catch number) from total by-catch weight respectively. The highest Biomass and number of by-catch belonged to small discard fishes with 4329. 02 tonnes and 4923244number respectively. On average By-catch-to-shrimp ratio was estimated 6. 18:1. Length data analysis indicated that whole caught specimens of P. argenteus، P. niger، S. commerson، C. dussumieri، C. nudus، O. ruber، S. forsteri and T. lepturus had a non-standard size for fishing.