Competition between freshwater fish and goldeneyes Bucephala clangula (L.) for common prey

Abstract

Results of a descriptive field study showed that goldeneyes preferred lakes without fish to those with fish. Field experiments were carried out in order to investigate whether or not this preference could be ascribed to a higher food supply in the lakes devoid of fish, as goldeneyes and some freshwater fish (perch and roach in the studied lakes) to some extent feed on the same kinds of prey. Changes in the abundance of prey common to fish and goldeneyes and the use by goldeneyes of lakes after experimentally changed predation pressure from fish were studied. Some aquatic insect groups, Cloeon larvae, Odonata larvae, water bugs, dytiscids, and Chaoborus larvae, proved sensitive to predation from fish. Goldeneyes increased their use of an experimental lake after fish were removed, and they used this lake more than an adjacent control lake. It is suggested that fish are able to reduce the availability of foods common to the goldeneyes to such an extent that the selection by the ducks of feeding localities is affected, and that exploitation competition between freshwater fish and goldeneyes may occur.

The establishment of a population of GoldeneyesBucephala clangulabreeding in Scotland

“…Furthermore, Goldeneyes typically feed on a wide range of invertebrates in the central parts of lakes, whereas Mallard and Teal tend to feed at the edge of lakes and Tufted Ducks mainly feed on molluscs. Goldeneyes are found to occur in higher numbers at lakes with low fish densities, possibly as a result of competition for invertebrate prey (Eriksson 1979), but do not appear to affect fish stocks per se.…”

Diversity and abundance of water birds in a subarctic lake during three decades

“…We believe that the high density of diving ducks in 2003 (Table 2) is related to this recurrence of attractive macro-invertebrates in the lake. This is supported by experimental studies on competition between fish and ducks in small lakes in Sweden (Eriksson 1979) and England (Giles 1994). In both cases, abundances of macroinvertebrates increased when fish were removed, and this had positive effects on the use of lakes by diving ducks.…”

Survival of Mallard ducklings Anas platyrhynchos and competition with fish for invertebrates on a flooded gravel quarry in England

“…Some coarse fish species eat similar invertebrates to Mallard (Eriksson 1979, Pehrsson 1984 and Goldeneye Bucephala clangula ducklings (McAllister Eadie & Keast 1982) and fish removal can result in an increase of certain benthic macroinvertebrates such as some crustacea and members of the family Chironomidae (Eriksson 1979, Gilinsky 1984, Morin 1984.…”

“…Eriksson (1979) showed that broods preferred lakes without fish and that their use of an experimental lake increased after fish were removed. Pehrsson (1 979) showed that the highest rate of food intake in Mallard ducklings occurred on lakes where fish had been removed, and further, by experiment Pehrsson (1984) showed that ducklings obtained more food in lakes where fish had been removed.…”

“…However, there are marked individual differences in home range size. Recent work has shown that competition with fish for invertebrates could affect brood home ranges (Eriksson 1979, Andersson 1981, McAllister Eadie & Keast 1982, Pehrsson 1984. Fish density could therefore affect duckling survival, particularly on flooded quarries which have been stocked with fish for sport.…”