Many of what are often considered the best documented examples of endocrine disruption in wildlife have featured aquatic organisms, possibly because the aquatic environment is the ultimate sink for most chemicals, and hence aquatic organisms may receive higher exposures than terrestrial organisms. These studies have focused primarily on one species of freshwater fish, the roach (Rutilis rutilis), which is often the commonest fish in many waters and which comprises a significant proportion of the diet of the predatory fish present. Hence, if chemicals are responsible for the endocrine disruption observed in the roach, it is possible that these could accumulate in predators eating affected roach (and other species), leading to effects occurring in these predators. To date, there are no reports of endocrine disruption occurring in any top predator. This project addresses this gap in our knowledge, by determining whether or not endocrine disruption is occurring in top predator fish.
To seek evidence of endocrine disruption in three species of top predator fish, namely pike (Esox lucius), perch (Perca fluviatilis), and zander (Stizastedion lucioperca; sometimes called pike-perch).