Helminth communities of loggerhead turtles (Caretta caretta) from Central and Western Mediterranean Sea: The importance of host's ontogeny

Abstract

We investigated the factors providing structure to the helminth communities of 182 loggerhead sea turtles, Caretta caretta, collected in 6 localities from Central and Western Mediterranean. Fifteen helminth taxa (10 digeneans, 4 nematodes and 1 acanthocephalan) were identified, of which 12 were specialist to marine turtles; very low numbers of immature individuals of 3 species typical from fish or cetaceans were also found. These observations confirm the hypothesis that phylogenetic factors restrict community composition to helminth species specific to marine turtles. There were significant community dissimilarities between turtles from different localities, the overall pattern being compatible with the hypothesis that parasite communities reflect the ontogenetic shift that juvenile loggerheads undergo from oceanic to neritic habitats. The smallest turtles at the putative oceanic, pelagic-feeding stage harboured only the 2 digenean species that were regionally the most frequent, i.e. Enodiotrema megachondrus and Calycodes anthos; the largest turtles at the putative neritic, bottom-feeding stage harboured 11 helminth taxa, including 3 nematode species that were rare or absent in turtles that fed partially on pelagic prey. Mean species richness per host was low (range: 1.60-1.89) and did not differ between localities. Variance ratio tests indicated independent colonization of each helminth species. Both features are expected in ectothermic and vagrant hosts living in the marine environment.

Helminths of hawksbill turtle (Eretmochelys imbricata) from the Pacific coast of Costa Rica

“…The turtle in this study had ingested mainly algae that is unusual for this species and would indicate inability to forage effectively in its environment. It might explain the rich helminth fauna here found since sea turtles with vegetarian diet would ingest accidentally and more easily great amount of mollusk intermediate hosts whose live on marine pasture with respect to turtles with mainly spongivorous or carnivorous habits (Pérez Ponce de León et al, 1996;Santoro et al, 2006Santoro et al, , 2010Santoro & Mattiucci, 2009). Infection by spirorchiid flukes represents the main parasitological health problem of sea turtles.…”

“…Studies on sea turtles suggest that ontogenetic and ecological factors influence strongly their helminth communities (Pérez Ponce de León et al, 1996;Santoro et al, 2006Santoro et al, , 2010. Unfortunately, no information exists on helminth community of hawksbill turtle at both hierarchical levels of organization (the component community and infracommunity), and the known data is fragmented and based on occasional findings of stranded individuals (Oguro, 1936;Chattopadhyaya, 1972;Fischthal & Acholonu, 1976;Dyer et al, 1995;Werneck et al, 2008;Greiner, 2013).…”

Report of Enodiotrema megachondrus (Looss, 1899) Looss, 1901 (Digenea: Plagiorchiidae) in a green turtle Chelonia mydas Linnaeus, 1758 (Testudines, Cheloniidae) from Brazil

“…2F). Previous records: In C. caretta from Egypt (Braun, 1901;Looss, 1899); France (Euzet & Combes, 1962); Italy (Manfredi et al, 1998); Mediterranean (Aznar et al, 1998;Santoro et al, 2010); Madera (Valente et al, 2009), Adriatic sea (Gracan et al, 2012) and USA (Greiner, 2013); C. mydas from Egypt (Looss, 1902), USA (Greiner, 2013) and Brazil (Present report); E. imbricata from Cuba (Groschaft et al, 1977); L. olivacea from Mexico (Pérez-Ponce de León et al, 1996;Vivaldo et al, 2006) and Costa Rica (Santoro & Morales, 2007) and L. kempii from and USA (Greiner, 2013).…”

“…microvitellatus Chattopadhyaya, 1970; E. schikhobalovae Gupta & Mehrotra 1976 and E. carettae Blair & Limpus 1982. Although these parasites are carried out at various locations in the world, on different hosts (Santoro et al, 2010), None of these species have previously been reported in hosts found in the SouthWest Atlantic Ocean (Fernandes & Kohn, 2014). The aim of this note is report the fi rst occurrence of E. megachondrus in a juvenile Chelonia mydas Linnaeus, 1758 from Brazil.…”

Spatiotemporal distributions of intestinal helminths in female lesser scaupAythya affinisduring spring migration from the upper Midwest, USA

“…During spring migrations of 2014 and 2015, we identified and enumerated intestinal helminths in 130 scaup from stopover locations in four regions of the upper Midwest, to examine the effects of host age and body size as well as the region and year of collection on helminth infracommunity structure (Santoro et al, 2010(Santoro et al, , 2012Kanarek & Zaleśney, 2013). Results from this investigation will be valuable for identifying possible relationships between intestinal helminth communities and key stopover locations of spring-migrating scaup.…”