The muscle twitch and the maximum swimming speed of giant bluefin tuna, Thunnus thynnus L.

Abstract

Sustained swimming of bluefin tuna was analysed from video recordings made of a captive patrolling fish school [lengths (L) 1.7-3.3 m, body mass (M) 54433 kg]. Speeds ranged from 0.6 to 1.2 L s-' (86260 km day-') while stride length during steady speed swimming varied between 0.54 and 0.93 L. Maximum swimming speed was estimated by measuring twitch contraction of the anaerobic swimming muscle in pithed fish 5 min after death. Muscle contraction time increased from the shortest just behind the head (3G50ms at 20% L) to the longest at the tail peduncle (8G90 ms at 80% L) (all at 28" C). A fish (L= 2.26 m) with a muscle contraction time of 50 ms at 25% L can have a maximum tail beat frequency of 10 Hz and maximum swimming speed of 15 m s -I (54 km h-') with a stride length of 0.65 L. With a stride length of 1 L a speed of 22.6 m s-' (81.4 km h-') is possible. Power used at maximum speed was estimated for this fish at between IOand40 kW, withcorrespondingvaluesforthedragcoefficient at a Reynoldsnumber of 4.3 x 10' of 0,0007 and 0.0027.

Optimal shape and motion of undulatory swimming organisms

“…Assumed body/muscle/fluid properties For simplicity, in all our calculations muscle and tissue properties are taken as length and size independent, but characteristic for fishes (red fibre isometric force Figure 5. Comparisons of shape and swimming characteristics between model predictions and representative fish and cetacean species [20,[45][46][47]. In each example, from optimal populations P(m) that cover the species' standard range of m (double arrowhead line), an organism (asterisks) is selected that best matches kinematic data and shape for that species.…”

Effects of body mass on physiological and anatomical parameters of mature salmon: evidence against a universal heart rate scaling exponent

“…Wardle et al, 1989;Kaji et al, 1996). Body mass can affect the rate of all biological processes from cellular metabolism to population dynamics (Schmidt-Nielsen, 1989).…”

Moving with the beat: heart rate and visceral temperature of free-swimming and feeding bluefin tuna

“…This statement encapsulates the inherent difficulties associated with examining cardiorespiratory function in the most active and highly evolved predatory fishes in the ocean, the tuna. Tuna can grow to 680 kg in mass and 3.5 m in length, they must swim continuously to ram ventilate their gills and maintain hydrodynamic lift, they can reach burst swimming speeds of approximately 70 km h K1 , and they use vascular heat exchangers to maintain regions of their body at temperatures up to 208C above ambient seawater ( Walters & Fierstine 1964;Carey & Gibson 1983;Collette & Nauen 1983;Wardle et al 1989;Brill et al 1994;Fudge & Stevens 1996). The difficulties of working with tuna are compounded because they are expensive to acquire, difficult to maintain in captivity, and relatively few are available for study (Brill & Bushnell 2001).…”