Assessment of fish trophic status and relationships by stable isotope data in the coral reef lagoon of New Caledonia, southwest Pacific

Laure Carassou, Michel Kulbicki, Thomas J R Nicola, Nicholas V C Polunin

Research output: Contribution to journalArticle

34 Citations (Scopus)

Abstract

This study examines the trophic status and relationships of coral reef fish in the lagoon of New Caledonia, southwest pacific. The feeding habits of 34 fish species collected at three contrasted sites were first described using a compilation of gut contents observations and data from the literature. The carbon and nitrogen isotope signatures of these fish and of some of their potential ultimate food sources were also determined at each site. Despite some spatial variations in the isotopic signatures of most food sources and fish trophic groups, the overall trophic structures of fish assemblages were similar at the three sites. Stable isotope data were then used to re-assign fish species to trophic groups based on the δ15N signatures of fish and their food sources. Herbivorous fish species were clearly distinguished from the other trophic groups by their lower δ15N signatures, consistent with an estimated trophic position of ∼2 for all species examined. Scaridae were however characterized by relatively higher δ13C and lower δ15N, which is probably linked with the role of detritus in their diet. The estimated trophic positions of planktivorous fish species were consistent with their gut contents-based classification. Conversely, the isotopic signatures of carnivorous and piscivorous fish species largely overlapped, and their estimated trophic positions were much lower than expected. This suggests that these species feed over a broader range of trophic levels and food sources than implied by the gut contents observations, and indicates that their diet is partly omnivorous. Finally, the relationships between body mass and the isotopic signatures of four fish species were significant for at least one isotopic ratio for each species. Since ontogenetic variations and omnivorous diets are difficult to assess with gut contents data only, stable isotopes revealed essential in estimating the actual trophic status and relationships characterizing the fish species under study.

Original languageEnglish
Pages (from-to)1-12
Number of pages12
JournalAquatic Living Resources
Volume21
Issue number1
DOIs
Publication statusPublished - Jan 2008

Fingerprint

trophic status
New Caledonia
trophic relationships
coral reefs
stable isotopes
stable isotope
fish
digestive system
food
diet
trophic levels
coral reef lagoon
Scaridae
trophic structure
nitrogen isotope
isotopic ratio
trophic level
body mass
detritus
coral reef

Keywords

  • Coral reef fish
  • Gut contents
  • Ontogenetic variability
  • Pacific Ocean
  • Stable isotopes
  • Trophic position

ASJC Scopus subject areas

  • Aquatic Science

Cite this

Assessment of fish trophic status and relationships by stable isotope data in the coral reef lagoon of New Caledonia, southwest Pacific. / Carassou, Laure; Kulbicki, Michel; Nicola, Thomas J R; Polunin, Nicholas V C.

In: Aquatic Living Resources, Vol. 21, No. 1, 01.2008, p. 1-12.

Research output: Contribution to journalArticle

Carassou, Laure ; Kulbicki, Michel ; Nicola, Thomas J R ; Polunin, Nicholas V C. / Assessment of fish trophic status and relationships by stable isotope data in the coral reef lagoon of New Caledonia, southwest Pacific. In: Aquatic Living Resources. 2008 ; Vol. 21, No. 1. pp. 1-12.
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