Foraging niche segregation between juvenile and adult hawksbill turtles (Eretmochelys imbricata) at Príncipe island, West Africa

Ferreira, Rogério L.; Ceia, Filipe R.; Borges, Teresa C.; Ramos, Jaime A.; Bolten, Alan B.

Publication

Foraging niche segregation between juvenile and adult hawksbill turtles (Eretmochelys imbricata) at Príncipe island, West Africa

2018-01Journal article

dc.contributor.author	Ferreira, Rogério L.
dc.contributor.author	Ceia, Filipe R.
dc.contributor.author	Borges, Teresa C.
dc.contributor.author	Ramos, Jaime A.
dc.contributor.author	Bolten, Alan B.
dc.date.accessioned	2018-02-08T11:42:59Z
dc.date.available	2020-01-01T01:30:12Z
dc.date.issued	2018-01
dc.description.abstract	Hawksbill sea turtles are the most tropical sea turtle species with one of the last remaining aggregations in West Africa found on Príncipe Island (1° 37′ N; 7° 23′ E). Here we present for the first time, data on the trophic and foraging ecology of both juvenile and adult hawksbill turtles found in the shallow waters of Príncipe, using stable isotope analyses of carbon (δ13C) and nitrogen (δ15N), and assess any isotopic niche segregation between these two life-stages. Hawksbill turtles were sampled from December 2012 to June 2014, complementary to a snorkeling survey conducted around the entire coastline (ca. 100 km). δ13C and δ15N values were measured in epidermal samples of 40 individuals and analyzed in the context of isotopic niche width and overlap (i.e. trophic and foraging niches). Juveniles hawksbills (n = 29; < 60 cm curved carapace length (CCL)) occupy a significant smaller isotopic niche than adults (n = 11; > 75 cm), especially in relation to δ13C values (i.e. habitat use) but also in δ15N values (i.e. trophic level). Variances between adults and juveniles were not homogenous for both isotopes and larger for adults, particularly for δ13C values. We found significant differences in δ13C values between the two groups, but not for δ15N, and a significant correlation between δ13C values and CCL for the pooled data. SIBER (stable isotopes Bayesian ellipses in R) outcomes support these results and, although niches are not completely segregated, it indicates spatial foraging segregation between juveniles and adults. The fact that Príncipe Island's shallow waters are constantly being patrolled by spearfishermen, together with the existence of a large insular platform and a superior dive capacity in larger hawksbills, might influence this segregation. Our results suggest that part of the adults may be originating from isotopically distinct areas. To have a better understanding on the distribution and abundance of the sea turtle populations in Príncipe, including their connectivity with other foraging and breeding areas, future in-water studies focused mainly on the entire insular platform of Príncipe, but also on the adjacent probable foraging areas of the Gulf of Guinea, are required.	pt_PT
dc.description.version	info:eu-repo/semantics/publishedVersion	pt_PT
dc.identifier.doi	10.1016/j.jembe.2017.10.005	pt_PT
dc.identifier.issn	0022-0981
dc.identifier.other	AUT: TBO00930;
dc.identifier.uri	http://hdl.handle.net/10400.1/10367
dc.language.iso	eng	pt_PT
dc.peerreviewed	yes	pt_PT
dc.publisher	Elsevier	pt_PT
dc.rights.uri	http://creativecommons.org/licenses/by/4.0/	pt_PT
dc.subject	Sea turtle	pt_PT
dc.subject	Isotopic niche	pt_PT
dc.subject	Stable isotope	pt_PT
dc.subject	Life stage	pt_PT
dc.subject	Habitat use	pt_PT
dc.subject	Gulf of Guinea	pt_PT
dc.title	Foraging niche segregation between juvenile and adult hawksbill turtles (Eretmochelys imbricata) at Príncipe island, West Africa	pt_PT
dc.type	journal article
dspace.entity.type	Publication
oaire.citation.endPage	7	pt_PT
oaire.citation.startPage	1	pt_PT
oaire.citation.title	Journal of Experimental Marine Biology and Ecology	pt_PT
oaire.citation.volume	498	pt_PT
person.familyName	Borges
person.givenName	Teresa Cerveira
person.identifier.ciencia-id	5A1E-E8AD-3E24
person.identifier.orcid	0000-0002-6414-0083
person.identifier.rid	M-3388-2013
person.identifier.scopus-author-id	6604001208
rcaap.rights	openAccess	pt_PT
rcaap.type	article	pt_PT
relation.isAuthorOfPublication	7975c9b8-d25a-4bec-91f4-d1193a8e8082
relation.isAuthorOfPublication.latestForDiscovery	7975c9b8-d25a-4bec-91f4-d1193a8e8082