Parasitism by the rhizocephalan Peltogaster paguri Rathke, 1842 and hyperparasitism by the bopyrid isopod Liriopsis pygmaea (Rathke, 1843) on Pagurus hirsutiusculus (Dana, 1851) in Southeastern Alaska.

[The hairy hermit crab Pagurus hirsutiusculus was sampled from the low intertidal at two sites in Auke Bay, southeastern Alaska (58°22′N 134°40′W) to examine the prevalence of rhizocephalan parasitism. One site was exposed to wave activity while the other was sheltered. Two species of rhizocephalan, Peltogaster paguri and Peltogasterella gracilis, were found. Peltogaster paguri parasitized 12.6% of the crabs at the sheltered site and 13.4% at the exposed site. Rhizocephalan parasitism was not correlated with crab size at either site. One crab from the sample was infected with the rhizocephalan Peltogasterella gracilis. Also found was a bopyrid isopod, Liriopsis pygmaea, that hyperparasitized 36% of the Peltogaster paguri. This is the first report of Peltogaster paguri and Peltogasterella gracilis parasitizing Pagurus hirsutiusculus and the first record of both rhizocephalans from southeastern Alaska. The bopyrid isopod Liriopsis pygmaea is also reported from southeast Alaska, previously having been reported from Puget Sound. The incidence of infection of Peltogaster paguri in Alaska was higher than previously reported from other areas. Le pagure Pagurus hirsutiusculus a ete echantillonne a maree basse sur deux sites a Auke Bay, sud de l'Alaska (58°22′N 134°40′W) pour examiner la prevalence du parasitisme par des rhizocephales. Un des sites etait expose a l'action des vagues, tandis que l'autre etait abrite. Deux especes de rhizocephales, Peltogaster paguri et Peltogasterella gracilis ont ete identifiees. Peltogaster paguri parasitait 12,6% des pagures sur le site abrite et 13,4% sur le site expose. Le parasitisme des rhizocephales n'est correle a la taille des pagures sur aucun des sites. Un seul pagure etait infecte par Peltogasterella gracilis. Un isopode bopyrien, Liriopsis pygmaea, a ete egalement trouve, hyperparasitant 36% des Peltogaster paguri. Ceci constitue la premiere observation de Peltogaster paguri et Peltogasterella gracilis parasitant Pagurus hirsutiusculus et la premiere observation de ces deux rhizocephales pour le sud de l'Alaska. L'isopode bopyre, Liriopsis pygmaea, deja connu de Puget Sound, est aussi signale du sud-est de l'Alaska. L'incidence d'infection de Peltogaster paguri en Alaska est superieure a celle d'autres regions., The hairy hermit crab Pagurus hirsutiusculus was sampled from the low intertidal at two sites in Auke Bay, southeastern Alaska (58°22′N 134°40′W) to examine the prevalence of rhizocephalan parasitism. One site was exposed to wave activity while the other was sheltered. Two species of rhizocephalan, Peltogaster paguri and Peltogasterella gracilis, were found. Peltogaster paguri parasitized 12.6% of the crabs at the sheltered site and 13.4% at the exposed site. Rhizocephalan parasitism was not correlated with crab size at either site. One crab from the sample was infected with the rhizocephalan Peltogasterella gracilis. Also found was a bopyrid isopod, Liriopsis pygmaea, that hyperparasitized 36% of the Peltogaster paguri. This is the first report of Peltogaster paguri and Peltogasterella gracilis parasitizing Pagurus hirsutiusculus and the first record of both rhizocephalans from southeastern Alaska. The bopyrid isopod Liriopsis pygmaea is also reported from southeast Alaska, previously having been reported from Puget Sound. The incidence of infection of Peltogaster paguri in Alaska was higher than previously reported from other areas. Le pagure Pagurus hirsutiusculus a ete echantillonne a maree basse sur deux sites a Auke Bay, sud de l'Alaska (58°22′N 134°40′W) pour examiner la prevalence du parasitisme par des rhizocephales. Un des sites etait expose a l'action des vagues, tandis que l'autre etait abrite. Deux especes de rhizocephales, Peltogaster paguri et Peltogasterella gracilis ont ete identifiees. Peltogaster paguri parasitait 12,6% des pagures sur le site abrite et 13,4% sur le site expose. Le parasitisme des rhizocephales n'est correle a la taille des pagures sur aucun des sites. Un seul pagure etait infecte par Peltogasterella gracilis. Un isopode bopyrien, Liriopsis pygmaea, a ete egalement trouve, hyperparasitant 36% des Peltogaster paguri. Ceci constitue la premiere observation de Peltogaster paguri et Peltogasterella gracilis parasitant Pagurus hirsutiusculus et la premiere observation de ces deux rhizocephales pour le sud de l'Alaska. L'isopode bopyre, Liriopsis pygmaea, deja connu de Puget Sound, est aussi signale du sud-est de l'Alaska. L'incidence d'infection de Peltogaster paguri en Alaska est superieure a celle d'autres regions.]