Influence of activity and salinity on the weight-dependent oxygen consumption of the rainbow troutSalmo gairdneri

✍ Scribed by G. Madan Mohan Rao

• Publisher: Springer-Verlag
• Year: 1971
• Tongue: English
• Weight: 799 KB
• Volume: 8
• Category: Article
• ISSN: 0025-3162
• DOI: 10.1007/bf00355217

✦ Synopsis

Standard and active rates of oxygen consumption of rainbow trout (Salmo gairdneri) acclimated and tested at 5 ~ and 15 ~ in various salinities (fresh water to 30%o S) were determined. The fish used in experiments ranged in weight from 23 to 196 g. The relation between body weight and metabolism is discussed. Lowest rates of oxygen consumption were obtained in 7.5~o S at both temperatures and at all levels of activity; maximum rates were obtained in 30~oo S (with the exception of smaller fish at t5 ~ Reduction in osmotic load/ cost of osmoregulation is suggested as the probable cause for the lowest rate of oxygen consumption in 7.5~oo S, a salinity isosmotic with the plasma of the fish. Increase in temperature results in increase of metabolic rate. However, this has no effect on the slope of the weight--metabolism regression line. In 30~oo S at ~5 ~ the response at higher levels of activity seems to be size-dependent. The slope of the regression line (weight versus oxygen consumption) increases with increasing activity at 15 ~ this is more pronounced in 30~oo S. However, at 5 ~ no significant statistical difference was observed between the slopes. The scope for activity was calculated. It was found to be lowest in 7.5~oo S, and the scopes in fresh water and 15~oo S were not different. The scope in 30~oo S was high at 5 ~ but, at t5 ~ a reduced scope was found for smaller fish; this is a reflection of the earlier observation that small fish were unable to survive in a high salinity/high temperature combination.