Length-Weight Relationships of Four Fish Species Associated to Shrimp Trawl Fishery as by-Catch in the Persian Gulf, Iran

Length-length relationships (LLRs) and length-weight relationships (LWRs) were determined for four marine fish from Iranian waters of the Strait of Hormuz: Pseudotriacanthus strigilifer , Rhinobatos annandalei , Muraenesox cinereus , Nematalosa nasus belonging to four families Triacanthidae, Rhinobatidae, Muraenesocidae, Clupeidae. Specimens were collected monthly between October to December 2018 from artisanal shrimp vessels equipped with non-selective bottom trawl net (with mesh size of 20 and 40 mm, respectively at cod-end and body of trawl net). Trawling operation carried out in a depth range of 2 to 20 m. Total length (TL) (nearest to 0.1 cm) and body weights (nearest 0.1 g) were taken each individual. The result of this research provides first length-weight relationship references for R. annandalei and P. strigilifer and first LLR for R. annandalei and new maximum total length for M. cinereus . Estimated parameters of the LLR and LWR models ( a and b value) of the equation W B = a(TL) b and TL = a + b(SL) were highly significant ( P < 0.01) with a reliable coefficient of determination (R 2 ) ranged from 0.967 to 0.99.