Difference in factors explaining growth rate variability in European eel subpopulations: the possible role of habitat carrying capacity

• Published in: Ecology of Freshwater Fish
• Main Authors: Boulenger, Clarisse, Crivelli, Alain J., Charrier, Fabien, Roussel, Jean-Marc, Feunteun, Eric, Acou, Anthony
• Other Authors: Biologie des Organismes et Ecosystèmes Aquatiques (BOREA), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université des Antilles (UA), Station Biologique de la Tour du Valat, Fish Pass, Écologie et santé des écosystèmes (ESE), Institut National de la Recherche Agronomique (INRA)-AGROCAMPUS OUEST
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2016
• Subjects: density-dependent growth; carrying capacity; temperature; habitat; passive; anguilla-anguilla l; salmon salmo-salar; structured fish populations; small coastal catchment; atlantic salmon; brown trout; phenotypic plasticity; new-zealand; primary productivity; [SDV]Life Sciences [q-bio]; New Zealand; Tremblay; Anguilla anguilla; Atlantic salmon; Salmo salar
• Online Access: https://hal.science/hal-01453892; https://doi.org/10.1111/eff.12209

This study was funded by the 'Region Bretagne', the MAVA Foundation and 'Bretagne Grands Migrateurs'. The surveys and sampling were organised and operated by the company FISH PASS and the association 'Coeur Emeraude' in the Fremur River, and the INRA-Rennes and ONEMA in the Oir River. We are especially grateful to Frederic Marchand (INRA), Julien Tremblay (INRA), Richard Delanoe (ONEMA), Virgile Mazel (FISH PASS), Sebastien Quinot (FISH PASS) and all the people that helped with sampling and data gathering. We are also grateful to ORE PFC for the salmonids data. We are grateful to the two referees and to Anne Lize for their helpful comments. As a key parameter in the management of fish populations, individual growth rate (GR) variations were examined in the European eel (Anguilla anguilla; >150mm) using extensive mark-recapture surveys in the lotic habitats of two small rivers of western France: the Fremur, supposed to be saturated, and at the same latitude, the Oir with densities fivefold lower than those of the Fremur. In both systems, generalised linear models were used to test whether spatiotemporal factors such as dominant habitat type or local density affect GR variability. In the presumed unsaturated system, the Oir, GR variability is mainly explained by a set of habitat suitability drivers (density, dominant habitat type). In the Fremur, GRs appear independent of differences in habitat density or productivity. Below saturation, an increase in density will decrease the GR through intraspecific competition. At saturation, intraspecific competition reaches such high levels that regardless of eel density and productivity, the resources available by individual are similar throughout the system. In these circumstances, the effect of density on growth was presumed undetectable. Despite these contrasted results, mean GRs observed in both catchments were closed (similar to 20mmyear(-1)). This is an unexpected result as GR is expected to be higher in unsaturated systems. This similarity could be explained by ...