Prevalence and intensity of Portunus segnis Forskål, 1775 (Decapoda, Portunidae) infestation to metazoan symbionts on Band Abbas cost, Hormozgan province

The purpose of this study was to investigate the infestation of Portunus segnis with symbiotic organisms to determine the abundance, prevalence, and intensity of the infestation. A total of 86 blue swimming crabs were collected from Bandar Abbas coast during Summer and Autumn, 2018. Totally, 473 symbionts including Lepas anserifera, Chelonibia testudinaria, Philometra sp., Microstella norvegica, two unidentified species of order Cyclopoida, unidentified species of Ostracoda and Bivalvia were isolated. The prevalence of infection was 66.59, 1.47, 53, 13.5, 5.91, and 12.47%, respectively. Except for C. testudinaria, other taxa are reported for the first time in P. segnis and the Persian Gulf during this study. The intensity of infestation in both males and females did not show a significant difference, therefore, it can be concluded that this factor is not affected by gender in blue swimming crab. The intensity of infestation in autumn was approximately, four times more than summer (21 and 5.84, respectively). It is probably because of the suitable conditions and the larger size of the host in this season. Moreover, intensity of infestation in cluster 2 was almost four times more than in cluster 1, confirming the positive effect of size on the abundance of symbionts in P. segnis.