The theory of island biogeography predicts that the probability of a species occupying an island depends on a dynamic equilibrium between extinction and colonization. Epidermal papillomatosis is a disease manifesting as skin tumours on fish. We studied the factors affecting the occurrence of the disease in roach, Rutilus rutilus (L.), in 34 lakes. The results of discrimination analysis suggest ...

Environmental change may affect predator-prey interactions in lakes through deterioration of visual conditions affecting foraging success of visually oriented predators. Environmental change in lakes includes an increase in humic matter causing browner water and reduced visibility, affecting the behavioural performance of both piscivores and prey. We studied diurnal patterns of prey selection i...

1. By using a new video activity monitoring processor (Kaufmann, 1983) in conjunction with a large respirometer, we have measured swimming activity, oxygen consumption and reproductive investment (in the form of gonadal growth) of roach (Rutilus rutilus L.) during a seasonal cycle. 2. If the effect of temperature on metabolism is taken into account it can be shown that swimming activity is dras...

Acoustic stimuli within the sonic range are effective triggers of C-type escape behaviours in fish. We have previously shown that fish have an acute sensitivity to infrasound also, with acceleration thresholds in the range of 10(-5) m s(-2). In addition, infrasound at high intensities around 10(-2) m s(-2) elicits strong and sustained avoidance responses in several fish species. In the present ...

25 26 The functional response describes the relationship between feeding rate and prey density, and 27 is important ecologically as it describes how the foraging behaviour of an animal changes in 28 response to food availability. The effects of habitat complexity and food item size was 29 experimentally tested here on the foraging parameters and the functional responses of the 30 freshwater fis...