Power Output of Two Sizes of Atlantic Salmon (Salmo Salar) at Their Maximum Sustained Swimming Speeds

Abstract

The maximum sustained swimming speeds (Ums) for large (0.45 m long) and small (0.15 m) Atlantic salmon were respectively 0.91ms−1 and 0.54ms−1. Video and cin6 films of fish swimming close to Ums were analysed to obtain variables required for the application of two hydrodynamic models, those of Lighthill and Yates, to determine the mean thrust (T) and mean power output (P) at these swimming speeds (U) close to Ums. A large fish (‘Salmon’) and a small fish (‘Smolt’) were selected for analysis. For salmon using Lighthill's model, T=0.30N and P=0.26W, and using Yates' model, T=0.28N and P=0.25W (U/=0.87ms−1=0.96Ums). For smolt using Lighthill's model, T=0.0052N and P=0.0019W, and using Yates' model, T=0.0065 N and P=0.0024W (U=0.37ms−1=0.69Ums). The power output for smolt swimming at 0.69Ums was corrected to that required to swim at Ums, giving P=0.0059W (Lighthill's model) and P=0.0074W (Yates' model). At Ums it was assumed that all the red muscle was used. Two fish were selected from each size group and cross-sectioned to estimate their red muscle masses. Using a maximum mass-specific power output of 5–8 W kg− for slow red muscle fibres allowed us to calculate that the large and small fish have a power output capacity of 0.125–0.3 W and 0.007–0.019 W, respectively. The power output values at Ums derived from the different approaches for the large (0.25–0.26 W) and small (0.0059–0.0074 W) salmon agree closely. Effects of scaling are discussed.

Acoustic telemetry predation sensors reveal the tribulations of Atlantic salmon (Salmo salar) smolts migrating through lakes

“…Even though smolts exhibited slow progression rates in this study, the mean swimming speed within the lake was faster, because smolts made extensive movements in the lake, both downstream and upstream, before eventually reaching the lake outlet. Laboratory experiments have shown that Atlantic salmon smolts can swim at speeds of up to 0.54 m/s for a sustained period of time (Tang & Wardle, 1992), and Thorstad et al (2004) reported in situ mean swimming speeds of post‐smolts of 0.17 m/s. If the smolts followed the shortest path through the lake with a speed of 0.17 m/s, they could in theory traverse the lake in <11 h. Instead, surviving smolts from our field study spent a mean of 7.9 days in the lake and did not swim directionally through.…”

“…Laboratory experiments have shown that Atlantic salmon smolts can swim at speeds of up to 0.54 m/s for a sustained period of time (Tang & Wardle, 1992), and Thorstad et al (2004) reported in situ mean swimming speeds of post-smolts of 0.17 m/s. If the smolts followed the shortest path through the lake with a speed of 0.17 m/s, they could in theory traverse the lake in <11 h. Instead, surviving smolts from our field study spent a mean of 7.9 days in the lake and did not swim directionally through.…”

Analysis of Movements and Behavior of Bighead Carps (Hypophthalmichthys nobilis) Considering Fish Passage Energetics in an Experimental Vertical Slot Fishway

“…In this study, the carps' drag force values calculated in this paper were less than 21.942 × 10 −3 N. When the water thrust force (the reaction force of the individuals' drag force) is less than 0.6 × 10 −3 N, the fish is drifting with water, and when it is greater than 0.6 × 10 −3 N, the fish are in accelerated motion [32]. Considering the magnitude of the drag force of fish under the three typical hydraulic conditions in Figure 7, it can be concluded that the fish were in motion most of the time, which was consistent with the observations and video monitoring.…”