It is not just size that matters: shark cruising speeds are species-specific

Abstract

animal locomotion, Academic Press, New York, pp [333][334][335][336][337][338] 1977), which suggests that the relationship between cruising speed and length appears to be dominated by energetics. The results suggest that existing allometric estimates of cruising speeds can be improved by defining cruising speeds for each species as a function of length. Currently, literature presents cruising speed data for only a few species of shark; therefore, we provide a second, generalised model, which predicts cruising speed as a function of length and tail shape. The length + tail shape model was selected based on its generality and accuracy in estimating shark cruising speeds obtained from acoustic tags. This length + tail shape model was significantly better than a length only model; it explained a further 76 % of the variation in cruising speed derived from stereo-BRUVS and acoustic tagging data than a length only model. The more accurate prediction of the length + tail shape model is most likely because tail shape is correlated with a number of ecological factors.

Relations between morphology, buoyancy and energetics of requiem sharks

“…There should be an increase in swim speed with size, although the magnitude may not be large, which agrees with empirical studies showing larger sharks swimming faster [2,3]. We also predict that size could have an effect on buoyancy across and within the species.…”

Physical trade-offs shape the evolution of buoyancy control in sharks

“…We devised a new hydrodynamic model for idealized shark morphology and behaviour to explore the functional consequences of changes in liver size and associated buoyancy and body shape, in relation to drag production during steady and accelerated swimming (table 1; electronic supplementary material, Hydrodynamics methods). Specifically, our model was based on an idealized shark body (SL ¼ 1 m) of varying liver volume and associated buoyancy and routine swimming speeds (0.4-1.5 m s 21 ) [35]. The model was used to explore the functional consequences of different buoyancy control strategies, including the hydrodynamics of drag during steady swimming as a proxy for the energy economy of movement, and of the drag during accelerations to predict agility performance.…”

“…This initial speed (CS) was set as an independent parameter in the range 0.2-1.5 m s 21 commonly seen with most shark species and realistic maximum accelerations of 0.2-0.6 g [43]. Where the cruising speed is expected to be correlated with body size (standard length, SL), CS is parametrized as CS ¼ SL 0.44 þ INT per Ryan et al [35]. The detailed outputs are shown in figure 3; electronic supplementary material, S3 and tables S5-S7.…”

The importance of environment and life stage on interpretation of silky shark relative abundance indices for the equatorial Pacific Ocean

“…Silky sharks are born at about 65-81 cm TL (Oshitani et al, 2003; see also summary in Clarke et al, 2015), and therefore the spatial distribution of the EP small shark size category, which represents individuals of age <1 year, might be more likely to be influenced by movement of water masses than the spatial distribution of adults. Alternatively, if juvenile silky shark movement were the result of directed swimming, a cruising speed of 0.5 m/s (Filmalter, Cowley, Forget, & Dagorn, 2015;Ryan, Meeuwig, Hemmi, Collin, & Hart, 2015), for example, over a 1 year period would equate to more than 15,000 km/year, which at the equator would be about 142 degrees of longitude-more than enough to Figure 4) and the PDO (grey lines), by area and shark size category (where applicable). "rho": Spearman rank correlation coefficient (approximate 95% confidence intervals are shown in parentheses).…”