Occurrence and Prevalence of Heterosaccus dollfusi Boschma, 1960 (Rhizocephala: Sacculinidae) on Charybdis (Archias) longicollis Leene, 1938 (Brachyura: Portunidae) from Yumurtalık Cove, Iskenderun Bay (Northeastern Mediterranean)

This study investigated the prevalence and size-related distribution of the rhizocephalan parasite Heterosaccus dollfusi Boschma, 1960, infecting the invasive swimming crab Charybdis (Archias) longicollis in Yumurtalık Cove, Iskenderun Bay, northeastern Mediterranean Türkiye, between July 2014 and June 2015, excluding February. Monthly sampling was conducted using a bottom trawl at depths ranging from 0 to 50 m. In total, 951 crabs were examined, including 523 females (55.0%), 350 males (36.8%), and 78 juveniles (8.2%). The parasite was detected in 114 individuals, corresponding to an overall prevalence of 11.98%. Carapace width ranged from 7.12 to 100.60 mm, while body weight ranged from 1.34 to 164.09 g. Infected individuals had carapace widths between 26.57 and 78.27 mm, whereas larger individuals (>78 mm CW) were parasite-free. Parasite prevalence showed significant seasonal variation (χ² = 41.43, df = 20, P < 0.05), with higher infection frequencies recorded during the summer months. Despite the relatively high infection levels, no significant differences in carapace width were observed between parasitized and unparasitized crabs (ANOVA, P > 0.05). Overall, the findings confirm the stable coexistence of this invasive host–parasite system in Yumurtalık Cove (Iskenderun Bay, Türkiye).