VANN: Allee effects in Atlantic salmon caused by parasite infestation and interspecific hybridisation with brown trout

We propose to investigate the possibility that strong reduction of Atlantic salmon (Salmo salar) population sizes caused by infestation of the parasite Gyrodactylus salaris, coupled with increasing rates of interspecific hybridisation between Atlantic sal mon and brown trout (S. trutta), might lead salmon populations into local extinction by positive density-dependent processes collectively known as Allee effects. We will pursue this idea by developing models for host and parasite dynamics, including inter specific hybrids as hosts, based on detailed studies of hosts and parasites in long-term affected rivers. The project will be carried out by an internationally strong research team of fish population ecologists and geneticists, parasitologists, evolutiona ry biologists, biostatisticians and modellers, and will recruit research personnel at the PhD and postdoc levels.