Feeding behaviour of Anguilla anguilla and trophic resources in the Ingril Lagoon (Mediterranean, France)
- Authors:
-
BOUCHEREAU Jean-Luc,
MARQUES Catarina,
PEREIRA Patricia,
GUELORGET Olivier,
LOURIÉ Sven-Michel,
VERGNE Yvan
- Keywords:
-
lagoon ecosystems;
opportunism;
bioindicator;
mediterranean;
anguilla anguilla;
diet
- Abstract:
- This study focuses on the diet of the eel Anguilla anguilla, sampled during one month of each of the four seasons
from autumn 1998 to summer 1999 in the Languedocian Ingril Lagoon (Gulf of Lion). The following feeding indices were
calculated based on observations of 11 categories of prey found in the contents of full stomachs: coefficient of vacuity (CV),
degree of fullness (DR), occurrence frequency (PP, in %), relative abundance (N, in %) and relative weight (P, in %). A
parallel monitoring of the benthic macrofauna was conducted in autumn and spring. The interpretation of the results is
based on the degree III of the scale of confinement established by Guélorget & Perthuisot (1983) and on the Costello et al.
(1990) method, which combines PP and N. A. anguilla mainly feeds on benthic organisms, primarily amphipods
crustaceans, polychaetes, insect larvae and small fish. The eel's feeding activity is very low in November and February and
usually increases during May. The trophic quality available to the eel population in the Ingril Lagoon depends on its hydro-
dynamic variables, which are directly related to its close communication with the sea. Changes observed in the eel's diet
over this year long study illustrate an opportunist type of feeding behaviour that reflects the typical composition of the
macroinvertebrate species assemblage at a given point in time. Eels consume the type of benthic prey that is most available
at a given moment without using a particular feeding strategy (e.g., specialisation or generalisation). The eels adapt by
shifting their diet according to the energetic resources available in the ecosystem, which vary depending on hydrological
regime. Thus, the facultative catadromous migrant species Anguilla anguilla could be used as a bioindicator of changes in
the biological zonation and in the available food resources in the brackish ecosystem of Ingril Lagoon during its lagoon-
resident ecophase.
- Résumé :
- Comportement alimentaire de l'anguille européenne Anguilla anguilla et disponibilité trophique dans la lagune
d'Ingril (Méditerranée, France). Les anguilles ont été échantillonnées à chacune des quatre saisons de l'automne 1998 à
l'été 1999. Les indices alimentaires suivants sont calculés à partir de l'observation de 11 catégories de proies dans les
contenus d'estomacs remplis : coefficient de vacuité CV, degré de remplissage DR, pourcentages de présence PP,
numérique N et pondéral P. L'interprétation des résultats est fondée sur le degré III de l'échelle de confinement établie par
Guélorget & Perthuisot (1983), et sur la méthode de Costello et al. (1990), qui conjugue PP et N. A. anguilla se nourrit
d'organismes benthiques, principalement de Crustacés Amphipodes, Polychètes, larves d'Insectes et petits Poissons.
L'activité alimentaire de l'anguille est très faible en Novembre et Février et augmente en mai. La qualité trophique offerte
Cah. Biol. Mar. (2009) 50 : 319-332
Reçu le 11 mai 2009 ; accepté après révision le 21 septembre 2009.
Received 11 May 2009; accepted in revised form 21 September 2009.
Introduction
Although the lagoons along the western French
Mediterranean coast have the same origin in terms of their
formation (Guélorget & Perthuisot, 1983 & 1992), each has
its own geomorphological characteristics (e.g., surface
area, depth, inputs of fresh or marine water, catchment area,
and the nature of sediment). These characteristics influence
the physico-chemical factors of the ecosystem, such as
salinity, temperature, and water renewal, which in turn
depend on climatic conditions. Fluctuations in these factors
during the various seasons cause significant variability in
the biological populations present, which in turn affects the
fish populations (Bouchereau, 1994 & 1995; Zamora, 1999;
Bouchereau et al., 1991 & 2000; Bouchereau & Chaves,
2003; Chaves & Bouchereau, 2004; Garnerot et al., 2004).
High primary production is one characteristic of lagoon
environments. Because of this,
![[PDF -Full Text]](images/icons/pdf.jpeg){kind=icon}