0000000000376479
AUTHOR
Tapani Valtonen
Cardiovascular, ventilatory and total activity responses of brown trout to handling stress
Changes in total activity, heart and ventilation rates were observed in 2-year-old brown trout, following handling stress, using non-contact bioelectronic monitoring equipment. Experiments were carried out in laboratory conditions at water temperatures below 4° C, Transfer between tanks as well as 5 min restraint stress increased the total activity of fish for 24 to 48 h, after which it declined to near the pre-stress level. The transfer and struggle both elevated the heart rate for 3 to 4 days. Ventilation rate was elevated to a maximum of about 30% above the nominal level and recovered within 3 to 4 days. Both heart and ventilation rates were higher in feeding fish relative to fasting fis…
Cardiovascular, ventilatory and haematological responses of brown trout (Salmo trutta L.), to the combined effects of acidity and aluminium in humic water at winter temperatures
Two year old brown trout (Salmo trutta L.) were exposed for 7 days to pH 4.7 alone and with aluminium at concentrations of 0.28 and 0.45 mg l−1, respectively, in the water of River Rutajoki, Central Finland. The labile aluminium accounted for less than 30% of the total added amount in the humic water. During the exposures the fish were monitored by a non-contact bioelectronic monitoring system which records heart and ventilation rates of the fish. Terminal blood samples were obtained to evaluate the degree of stress. No mortality occurred during any of the exposures. Acid stress alone and with aluminium caused an immediate acute response in heart and ventilation rates, which remained higher…
Acid stress in respect to calcium and magnesium concentrations in the plasma of perch during maturation and spawning
Plasma calcium and magnesium concentrations in perch,Perca fluviatilis, were monitored in an acid lake, Lake Iso Tenhetty (pH ∼5, Al concentrations 0.3–0.5 mg l-1) compared with a nearby reference lake, Lake Paijanne, in Southern Finland. The effect of acid stress could be noticed as 1/3 lower fecundity of perch in the acid lake. Plasma Ca concentrations were temporarily lower in the middle of the winter in the fish of the acid lake, and in April–May samples the situation was opposite. Plasma Mg concentration was also lower in the perch from the acid lake in midwinter months, when compared with the double as high values (∼3 mmol l-1) from the reference lake. Elevated level of plasma Mg have…