Abstract
Between 2015 and 2018, a total of 1656 fish specimens belonging to four elasmobranch species was collected from the Tunisian coast and examined for isopods. Two species of Cirolanidae, Natatolana borealis and Natatolana neglecta, are reported for the first time from the Tunisian coast. This study presents new data on the morphology, distribution and behaviour of the two species. This is the first record of Natatolana borealis on Mustelus mustelus, Mustelus punctulatus and Scyliorhinus canicula, and of Natatolana neglecta on the elasmobranch Raja clavata. The scavenging behaviour of N. borealis and N. neglecta on elasmobranchs showed that these two species present similar behaviour. We also noted that their impact on fisheries in the first hours of infestation was negligible as the infested fish specimens did not show any external or internal damages.