Oxygen consumption of active rainbow trout, Salmo gairdneri Richardson, derived from electromyograms obtained by radiotelemetry

Abstract

A radiotelemetry apparatus is described for sensing and transmitting electromyograms (EMGs) from free-swimming fish. EMGs are recorded from the epaxial muscles of adult rainbow trout during periods in spontaneous (= routine) activity, and forced-swim, respirometers. When such EMG records are integrated, subjected to spectral analysis, and computer-averaged, the EMG values (in pV) are highly correlated with the fish oxygen consumption during the activity periods. However, there is a marked difference between the regression slopes for oxygen v. EMG value for the data from the spontaneous, and forcedswim, respirometers; the former slope is the steeper. The probable explanation of this phenomenon is that whereas in forced swims the epaxial myomeres are responsible for most of the activity of the fish, in spontaneous activity other muscle systems ( e g of the lateral, dorsal and ventral fins) come to account for a greater relative proportion ofbody movement. The difference in slope, although great, is evidently a regular phenomenon. The shift from one regression to the other occurs at a fairly precise epaxial EMG value (c. 5 pV). This suggests that the laboratory calibration of EMG value in terms of oxygen consumption can be utilized in the wild so that EMG records from free-swimming fish, fitted with telemetry packages can be used to deduce oxygen consumption attributable to activity. It also appears that such records can be used as a guide to the type of activity of the fish, i.e. desultory movements or free cruising.

Effects of Subchronic Exposure to Aluminium in Acidic Water on Bioenergetics of Atlantic Salmon (Salmo salar)

“…EMG telemetry is one of the best techniques currently available for measuring swimming activity, as it allows continuous recordings to be made and can detect energy-demanding changes in speed, direction, and position (Weatherley et al, 1982;Kaseloo et al, 1992).…”

Swimming behavior and energetics of sharks

“…A telemetry system has been used to record electromyograms (EMGs) from epaxial muscles of trout as a measure of activity (Rogers et al 1984). Averaged EMG values were correlated to oxygen consumption rates measured in a respirometer, but separate regressions were obtained for spontaneous and forced swimming activity (Weatherley et al 1982). EMGs from opercular muscles have been proposed as a measure of metabolic rate, but opercular EMGs were not correlated with oxygen consumption under conditions of spontaneous activity in laboratory trout (Rogers and Weatherley 1983).…”

“…Ross et al (1981) determined tailbeat frequencies from electromyogram& (EMGs) obtained from trout, and Rogers et al (1984) developed a telemetry system using EMG transmitters to assess locomotory activity in free-ranging trout. Weatherley et al (1982) recorded electromyogram& from the axial musculature of trout which were correlated with oxygen consumption. They obtained separate correlations between EMG measurements and oxygen consumption rates under conditions of spontaneous and forced swimming, presumably due to the increased use of non-axial muscles during spontaneous activity.…”

“…Telemetered electromyogram& from swimming muscles also show promise as a measure of activity metabolism (Weatherley et al 1982). However, there are other factors affecting metabolic rate, such as temperature, feeding, and stress, which would not be detectable by monitoring activity, but which may be sufficiently correlated to changes in heart rate.…”

Rainbow trout Oncorhynchus mykiss energetic responsesto pulsed flows in the American River, California, assessed by electromyogram telemetry

“…Aerobic metabolism within the red (slowoxidative) muscles governs fish's oxygen demand at any particular temperature. Thus, it is likely that EMG generated by each myomere, and the activity of a whole segment of myomeres, will be closely correlated with their oxygen consumption rate (Weatherley et al 1982). EMG telemetry has been used to determine the energetic cost of migration (Hinch and Rand 1998;Standen et al 2002), the activity exhibited during pulses of flow in a regulated river (Murchie and Smokorowski 2004;Geist et al 2005), passage through potential barriers such as weirs, dams, and rapids (Hinch et al 1996;Quintella et al 2004), and to identify spawning activity (Brown et al 2006).…”