Trophic relationships between the farmed pearl oyster Pinctada margaritifera and its epibionts revealed by stable isotopes and feeding experiments

Type Article
Date 2016
Language English
Author(s) Lacoste EliseORCID1, Raimbault Patrick2, Harmelin-Vivien Mireille2, Gaertner-Mazouni Nabila1
Affiliation(s) 1 : Univ Polynesie Francaise, UMR EIO 241, F-98702 Faaa, Tahiti, France.
2 : Univ Toulon & Var, Aix Marseille Univ, CNRS INSU IRD, Inst Mediterraneen Oceanol MIO, F-13331 Marseille, France.
Source Aquaculture Environment Interactions (1869-215X) (Inter-research), 2016 , Vol. 8 , P. 55-66
DOI 10.3354/aei00157
WOS© Times Cited 3
Keyword(s) Ascidian, Biofouling, Trophic interactions, Stable isotope, Flow cytometry
Abstract

Bivalve cultures support a host of epibionts, mainly suspension feeders, which can compete for food resources with the cultivated bivalves. However, the magnitude of interspecific competition for food in bivalve aquaculture settings remains inconclusive, especially in tropical areas. We investigated the interactions for food between the farmed pearl oyster Pinctada margaritifera and its epibionts, using stable isotope analysis and feeding experiments. Inter-and intraspecific variations of delta C-13 and delta N-15 stable isotope ratios (SIRs) were determined for oysters in the presence or absence of epibionts. The diet of the most abundant epibionts, Herdmania momus and Didemnum sp., was specified using isotope measurements and flow cytometry during feeding experiments, to determine the main phytoplankton groups consumed by these ascidians in natural conditions. The absence of intraspecific variation in SIRs among oysters with or without epibionts suggested that the diet of P. margaritifera was not affected by the presence of epibionts, indicating a reduced diet overlap and no food limitation. The delta C-13 signature of ascidians (-21 parts per thousand) was lower than that of oysters (-18 parts per thousand), indicating a difference in organic matter sources ingested by these filter feeders despite receiving the same food mixture. While the main carbon source of oysters came from large particulate organic matter (POM) > 20 mu m, our results showed that the diet of ascidians mainly came from smaller particles (POM < 20 mu m) and reflects the composition of ambient water (mainly picophytoplankton < 2 mu m), which confirmed their lack of food selectivity. In the studied conditions, food competition between oysters and epibionts, specifically ascidians, was not a limiting factor, in spite of a diet overlap for nanophytoplankton.

Full Text
File Pages Size Access
Publisher's official version 12 1021 KB Open access
Top of the page

How to cite 

Lacoste Elise, Raimbault Patrick, Harmelin-Vivien Mireille, Gaertner-Mazouni Nabila (2016). Trophic relationships between the farmed pearl oyster Pinctada margaritifera and its epibionts revealed by stable isotopes and feeding experiments. Aquaculture Environment Interactions, 8, 55-66. Publisher's official version : https://doi.org/10.3354/aei00157 , Open Access version : https://archimer.ifremer.fr/doc/00664/77582/