Gill-net efficiency on fish catch based on economical and biological diversity indices

One of the most important methods for evaluating changes in an ecosystems is studying the biodiversity changes. This study sought to examine the changes of biodiversity in two different fishing grounds of the Persian Gulf. For this purpose, two fishing grounds were selected, Abumusa, Tonb and Siri as subarea 1, and Kish westward as subarea 2. The catching data were obtained from two fishing vessels in January 2010 and July 2011. To evaluate changes in diversity of the populations, Simpson index, economic diversity index, Shannon index and the Hill index were used. The species diversity in subarea 1 was higher than that in subarea 2. The percentage of total frequency was higher for Tunnus tonggol (53.34 and 37.64) and Euthynnus affinis (40.76 and 27.34) in both subareas. However, the economic diversification index was higher in subarea 2 and the evenness index was higher in subarea 1.