Infestation of Lithodes santolla (Decapoda: Lithodidae) by Pseudione tuberculata (Isopoda: Bopyridae) in San Jorge Gulf, Southwestern Atlantic Ocean

Abstract

The bopyrid isopod Pseudione tuberculata infests decapod crustacean species of the family Lithodidae. It has previously been found in Neolithodes diomedeae from Chile, in Lithodes santolla and Paralomis granulosa from the Beagle Channel and in L. santolla from the Magellan Strait. A case was detected in 1980 in San Jorge Gulf and since then no bopyrid has been found in any of the 12,300 specimens of Lithodes santolla studied from commercial captures. In the present study we collected and analysed 648 juveniles of Lithodes santolla measuring between 8.38 and 49.04 mm carapace length (CL) from shallow waters in the central area of San Jorge Gulf. Sixteen females of Pseudione tuberculata along with 12 attached males were recorded. Additionally, six exuviae showed branchial swelling but no parasites were found. An infestation of the right branchial chamber was observed only once. Ten bopyrid females were mature and six were immature. Prevalence was very low and closely related to the age and the habitat of young king crabs in open coastal waters. The infestation occurs during the first months following postlarval settlement, and the parasite reaches sexual maturity within the next year, before host juveniles leave the coastal waters. So, the entire life span of the bopyrid could occur in coastal waters.