Illegal shrimp fishing in Hormozgan inshore waters of the Persian Gulf

An observer program was conducted to study and quantify the dimensions of illegal shrimp fishing in Hormozgan inshore waters (the northern Persian Gulf). Catches were sampled from 54 replicate landings of three boats from July to October 2014. The catch composition by weight included 55.37% shrimp and 44.63% by-catch (25.90% discards and 18.73% incidental catch). Forty-one species belonging to 27 families constituted the by-catch species, which Portunidae and Leiognathidae families had the highest contribution of by-catch composition with 24.71% by weight and 16.71% in number, respectively. The catch rate (kg boat−1 day−1) of shrimps and by-catches were estimated as 16.056 ± 4.412 and 12.653 ± 2.686 using the non-parametric bootstrap method (α = 0.05). A randomized t-test comparison, with 1000 replicates, of by-catch species weight with weight of shrimps was not significant (P > 0.05). Using a Monte Carlo procedure through combining data of catch rate and the number of boats and fishing days, we estimated the annual IUU shrimp catch between 461.118 and 523.251 tons (α = 0.05), which is valued between 2.6 and 3 U.S. million dollars approximately. These results consider the first study on the illegal shrimp fisheries in the Persian Gulf, and could be helpful for marine fisheries managers in the region.