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Behavioural and heart rate responses to food limitation and predation risk: an experimental study on rainbow trout (1999)

Höjesjö, J. ; Johnsson, J. I. ; Axelsson, M.

Oxford, UK : Blackwell Publishing Ltd

Journal of fish biology 55 (1999), S. 0

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ISSN: 1095-8649

Source: Blackwell Publishing Journal Backfiles 1879-2005

Topics: Biology

Notes: Food-restricted rainbow trout Oncorhynchus mykiss maintained a lower basal heart rate than satiated fish, probably as a result of reduced metabolic rate. Food-restricted fish were also more active during feeding and were more willing to take risks than satiated fish. Both satiated and food-restricted fish were positioned lower in the tank after the predator attack. Heart rate increased more during feeding in the food-restricted fish compared to the satiated, but energy status had no general effect on the relation between heart rate and behaviour. Hence, the increase in heart rate was mainly a response to the more active foraging behaviour in the food-restricted fish. Moreover, behavioural activity in the food-restricted fish was associated with a higher heart rate after the predator attack than when the fish was undisturbed, which may reflect physiological preparation for flight. These findings suggest that behavioural and cardiac responses are coadapted to meet variation in food availability and predation risk in the wild.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1111/j.1095-8649.1999.tb00736.x

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Catecholamine release in heat-stressed Antarctic fish causes proton extrusion by the red cells (1998)

Forster, M. E. ; Davison, W. ; Axelsson, M. ; [et al.]

Springer

Journal of comparative physiology 168 (1998), S. 345-352

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ISSN: 1432-136X

Keywords: Key words Antarctic ; Catecholamines ; Nototheniid ; Red cell swelling ; Stress

Source: Springer Online Journal Archives 1860-2000

Topics: Biology , Medicine

Notes: Abstract Two species of Antarctic fish were stressed by moving them from seawater at −1 °C to seawater at 10 °C and holding them for a period of 10 min. The active cryopelagic species Pagothenia borchgrevinki maintained heart rate while in the benthic species Trematomus bernacchii there was an increase in heart rate. Blood pressure did not change in either species. Both species released catecholamines into the circulation as a consequence of the stress. P. borchgrevinki released the greater amounts, having mean plasma concentrations of 177 ± 54 nmol · l−1 noradrenaline and 263 ± 131 nmol · l−1 adrenaline at 10 min. Plasma noradrenaline concentrations rose to 47 ± 14 nmol · l−1 and adrenaline to 73 ± 28 nmol · l−1 in T. bernacchii. Blood from P. borchgrevinki was tonometered in the presence of isoprenaline. A fall in extracellular pH suggests the presence of a Na+/H+ antiporter on the red cell membrane, the first demonstration of this in an Antarctic fish. Treatment with the β-adrenergic antagonist drug sotalol inhibited swelling of red blood cells taken from temperature-stressed P. borchgrevinki, suggesting that the antiporter responds to endogenous catecholamines.