Field‐based measurements of oxygen uptake and swimming performance with adult Pacific salmon using a mobile respirometer swim tunnel

Abstract

Novel field measurements of critical swimming speed (Ucrit) and oxygen uptake ( Mo2) in three species of adult Pacific salmon Oncorhynchus spp. up to 3·5 kg in body mass were made using two newly designed, mobile Brett‐type swim tunnel respirometers sited at a number of field locations in British Columbia, Canada. Measurements of Ucrit, which ranged from 1· 68 to 2·17 body lengths s−1, and maximum Mo2, which ranged from 8·74 to 12·63 mg O2 kg−1 min−1 depending on the species and field location, were judged to be of similar quality when compared with available data for laboratory‐based studies. Therefore high quality respirometry studies were possible in the field using adult wild swimming salmonids. In addition, the recovery of wild adult Pacific salmon from the exhaustive Ucrit swim test was sufficiently rapid that swimming performance could be repeated with <1 h of recovery time between the termination of the initial swim test and the start of the second test. Moreover, this repeat swimming performance was possible without routine Mo2 being reestablished. This result suggests that wild adult salmon are capable of carrying a moderate excess post‐exercise oxygen consumption without adversely affecting Ucrit, maximum Mo2 or swimming economy. Such capabilities may be extremely important for timely migratory passages when salmonids face repetitive hydraulic challenges on their upstream migration.

Empirical Modelling of Solid-blocking Effect in a Blazka Respirometer for Gag, a Large Demersal Reef Fish

“…The λ-shape coefficient in this study was 0.5, confirming its use for the fusiform body shape of the grouper species used in this study. The area coefficient exponent (A exp ) value of 1.27 estimated in this study was lower than the value of 1.5 suggested by Bell and Terhune (1970) and used universally in other studies [7,8,10]. This lower value could result from parameters unaccounted for in the standard Bell and Terhune model, such as changes in inertial drag due to the swimming motion of the fish with corresponding changes in flow velocity, relative to an empty flume.…”

“…This velocity is assumed to be equal to the water velocity in the swimming chamber of the respirometer [4]. This water velocity is typically measured with either no fish present in the swimming chamber [7][8][9][10] or in a portion of the swimming chamber not restricted by the body of the fish [11,12]. However, depending on the maximum diameter of a fish, the body as a solid object can impede or block the flow of water in the swimming chamber.…”

Subclinical Listonella anguillarum infection does not impair recovery of swimming performance in rainbow trout Oncorhynchus mykiss

“…However, mortality has not been observed in any previous repeat swimming work (e.g. Jain et al 1997, Farrell et al 1998, Lee et al 2003.…”

“…After a 45 min recovery period at acclimation water speed (0.3 BL s -1 ), a second identical ramp-U crit test was given to determine U crit2 . The repeat U crit protocol was chosen since healthy salmonids are capable of repeating exhaustive swimming after as little as a 40 min recovery (Farrell et al 1998, Jain et al 1998, Lee et al 2003, whereas stressed or ill salmonids are not (Farrell et al 1998, Jain et al 1998, Tierney et al 2004.…”

“…However, mortality has not been observed in any previous repeat swimming work (e.g. Jain et al 1997, Farrell et al 1998, Lee et al 2003.Power analysis. For the main treatment (injected) groups of the disease experiments, power analysis was used to determine sample size.…”