PARASITE COMMUNITIES OF TWO SHARKS, ETMOPTERUS GRANULOSUS AND SCHROEDERICHTHYS BIVIUS, OF SOUTHERN CHILE: Parasite communities of two sharks, Etmopterus granulosus (Squaliformes) and Schroederichthys bivius (Carcharhiniformes), from Southern Chile Comunidades

The shark-parasite associations for most shark species in Chile are poorly known. Thus, the purpose of this study was to analyze the parasite community of two shark species from Southern Chile. A total of 24 specimens of the southern lanternshark Etmopterus granulosus, and seven specimens of the narrowmouthed catshark Schroederichthys bivius were collected from the Strait of Magellan during January of 2017 and 2018. We recorded a total of 87 parasites associated with the examined E. granulosus and 192 parasites associated with the examined S. bivius, with higher average of parasite abundance in the latter species (27.5 ± 25.5 parasites/host) compared to E. granulosus (3.5 ± 3.3 parasites/host). A few parasites were prevalent and abundant; the nematodes Pseudoterranova sp. (41.7% prevalence; 1.46 parasites/host) and Anisakis sp. (29.2% prevalence; 1.21 parasites/host) present in E. granulosos, whereas the copepod Tautochondria sp. (85.7% prevalence; 9.14 parasites/host) and the nematode Proleptus niedmanni (71.4% prevalence; 14.86 parasites/host) present in S. bivius. Similitude in terms of parasite composition between the two shark species was low (14.6%). Thus, despite the sympatry of the two sharks species analyzed in this study, the parasite composition was different because only two parasite species were shared, the anisakid nematodes Pseudoterranova sp. and Anisakis sp. Therefore, the difference in parasite composition of the E. granulosus and S. bivius could be due to their evolutionary history, involving several differences in the ecology of the hosts.