Phoretic sharksuckers (Echeneis naucrates) associated with an elasmobranch host occupy higher relative trophic positions

Marine Ecology Progress Series
By: , and 

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Abstract

The relationship between phoretic diskfishes and their hosts is a classic example of marine symbiosis, yet surprisingly few studies have quantified this trophic relationship. We investigated the hypothesis that by consuming host parasites and prey scraps phoretic diskfishes (Echeneidae) feed at a higher relative trophic position than free-living individuals through expanded foraging opportunities. We used carbon and nitrogen stable isotope analysis of muscle tissue from both free-living and commensal sharksuckers Echeneis naucrates and their hosts, supplemented with gut-content analysis, to investigate this hypothesis. Our analysis revealed that commensal sharksuckers likely occupy higher relative trophic positions than free-living sharksuckers. The importance of scavenging host prey decreased ontogenetically as sharksuckers shifted from symbiotic phoresis to free-swimming behavior, leading to an ontogenetic change in which obligately commensal juveniles occupy higher trophic positions than free-living adults which are only facultatively commensal. Relative differences in δ13C and δ15N among individual host-commensal pairs varied among host species, suggesting potential differences in foraging opportunities among host taxa.

Publication type Article
Publication Subtype Journal Article
Title Phoretic sharksuckers (Echeneis naucrates) associated with an elasmobranch host occupy higher relative trophic positions
Series title Marine Ecology Progress Series
DOI 10.3354/meps14002
Volume 687
Year Published 2022
Language English
Publisher Inter-Research Science Publisher
Contributing office(s) Great Lakes Science Center
Description 8 p.
First page 125
Last page 132
Additional publication details