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 WB = a(TL)b and TL = a + b(SL) were highly significant (P < 0.01) with a reliable coefficient of determination (R2) ranged from 0.967 to 0.99.