Physiological responses of over-wintering common carp (Cyprinus carpio) to disturbance by Eurasian otter (Lutra lutra)

Abstract

Using a tame animal, the impact of otter (Lutra lutra) disturbance on over-wintering carp (Cyprinus carpio) was monitored in two experiments, 133 and 140 days, respectively, over two consecutive winters (November-April). The level of stress in over-wintering carp exposed to various intensities of disturbance by otters was quantified using biological indicators of stress (cortisol, cortisone, indices of nitrogen, carbohydrate, lipid and mineral metabolism and activity of basic blood plasma enzymes) taken from blood plasma of stocked carp at the end of the winter seasons (when the photoperiod was 12 light:12 dark, respectively, 13L:10D). Moreover, condition (Fulton's coefficient of condition and fat content in muscles) and mortality rate of that carp were measured after over-wintering and also after the subsequent vegetation period. The analysis of blood and tissue samples of experimental fish showed changes in nitrogen, carbohydrate and mineral metabolism as well as levels of hormones and fat reserves. Higher response to stress in metabolism of carp with lower intensity of disturbance by otter suggests that high level of disturbance can lead to metabolic adaptation of carp to stress. The effect of stress on the mortality rate of carp during the over-wintering is not clear. Nevertheless, the negative effect of stress on survival, condition and growth rate of carp in the subsequent vegetation period was not observed.

Physiological Stress as a Fundamental Mechanism Linking Predation to Ecosystem Functioning

“…Gluconeogenesis of proteins should increase excretion of nitrogen wastes in the forms of ammonia, uric acid, or urea. Elevated levels of urea were found in European carp that were exposed to chronic risk of otter predation (Polednik et al 2008). Increased excretion of N-rich compounds should lead to an increase in the overall body C : N ratio.…”

“…Chronic predation risk leads to changes in prey body composition expected after the induction of gluconeogenesis. Chronic risk of dragonfly predation decreased protein content in damselflies (Stoks et al 2005) and increased glucose content in European carp (Polednik et al 2008), snow hares (Boonstra et al 1998), and Arctic ground squirrels (Hik et al 2001). Song sparrows exposed to elevated risk of predation increase free fatty acids levels relative to those of sparrows from lower-risk habitats (Clinchy et al 2004).…”

Evaluation of the physiological status of the Pacific sardine, Sardinops sagax caeruleus, acclimated to different thermal regimes based on selected blood parameters

“…These enzymes leak into blood plasma as a consequence of tissue damage or dysfunction (Ciereszko et al 1998;Oluah 1999). They had been extensively used to monitor the physiological status of fishes exposed to stressful conditions (Wells et al 1986;Poledník et al 2008). Another response that can help evaluate the effect of temperature is red blood cells (RBC) count.…”

Behavioural response of carp (Cyprinus carpio, L.) pond stock upon occurrence of hunting great cormorant (Phalacrocorax carbo sinensis) flocks

“…No other data dealing with the phenomenon of fish displacement due to cormorants feeding habits have been recorded or published so far. Fish stress response to disturbances caused by piscivorous predators was also studied by Poledník et al (2008) who observed the impact of Eurasian otter (Lutra lutra) feeding on the stock of carp ponds. The study was based on plasma biochemical indices assessments aimed at cortisol, glucose and lactate concentrations.…”