**6. References**


**16** 

*France* 

**Semi Aquatic Top-Predators as Sentinels of** 

**(***Lutra lutra***) and Osprey (***Pandion haliaetus***)** 

**Food Webs: The Case of Eurasian Otter** 

**in Loire River Catchment, France** 

*1Toxicology laboratory, VetAgro Sup, Marcy l'Etoile,* 

*2Muséum des Sciences Naturelles d'Orléans,* 

Charles Lemarchand1, René Rosoux2 and Philippe Berny1

**Diversity and Dynamics of Pesticides in Aquatic** 

The Eurasian otter (*Lutra lutra, Lutrinae*, figure 1) and the osprey (*Pandion haliaetus, Pandionidae*, figure 2), formerly widespread in Europe and in France, have strongly declined during the 20th Century, following direct persecutions, habitat alteration and pollution, and consecutively decline of main prey. Direct persecutions were perpetrated because both species were considered as active competitors for fishing activity: otters were massively trapped for fur, and osprey populations were dismantled by direct shot or egg destruction in nests. Otter and osprey are both semi-aquatic top-predators species: diet is highly dominated by fish, which constitute at least 80 % and almost 98-100 % of the averaged prey biomass consumed by otter and osprey, respectively. However, diet studies of otter and osprey never showed any strong predation impact on fish diversity or biomass in rivers (reviews in Poole, 1989; Thibault et al. 2001; Clavero et al. 2003; Britton et al. 2005; Kruuk, 2006; Dennis, 2008). This diet specificity influence otter physiological characteristics: by comparison with other mammalian carnivores, a specific diversity and accumulation pattern of essential fatty acids of aquatic origin from food to otter tissues was recently shown (Koussoroplis et al. 2008). Another diet characteristic of both species is the diversity of prey and their opportunistic hunting behaviour: almost all fish species available in otter or osprey local habitat are able to be consumed, depending on hunting conditions, with important diet variations between seasons, during life cycle or between populations. This is particularly true concerning osprey, a migrating species present in northern and western Europe during reproductive season, and wintering from southwestern Europe to sub-Saharan Africa, but was also observed concerning sedentary otter. Because of their high trophic level, habitat requirements and main ecological characteristics, otter and osprey can be considered as good sentinels and indicator species of global contamination and biomagnification of toxic contaminants in aquatic food webs of large rivers, estuaries,

**1. Introduction** 

reservoirs and lakes.

