Effect of weight and frontal area of external telemetry packages on the kinematics, activity levels and swimming performance of small‐bodied sharks

Abstract

This study sought to observe the effects of submerged weight and frontal cross-sectional area of external telemetry packages on the kinematics, activity levels and swimming performance of small-bodied juvenile sharks, using lemon sharks Negaprion brevirostris (60-80 cm total length, L ) as a model species. Juveniles were observed free-swimming in a mesocosm untagged and with small and large external accelerometer packages that increased frontal cross-sectional area of the animals and their submerged weight. Despite adhering to widely used standards for tag mass, the presence of an external telemetry package altered swimming kinematics, activity levels and swimming performance of juvenile N. brevirostris relative to untagged individuals, suggesting that tag mass is not a suitable standalone metric of device suitability. Changes in swimming performance could not be detected from tail-beat frequency, which suggests that tail-beat frequency is an unsuitable standalone metric of swimming performance for small N. brevirostris. Lastly, sharks experienced treatment-specific changes in activity level and swimming kinematics from morning to afternoon observation. Therefore, the presence of external telemetry packages altered the kinematics, activity levels and swimming performance of small young-of-the-year N. brevirostris and these data may therefore be relevant to other similar-sized juveniles of other shark species.

Metabolic rates and the energetic cost of external tag attachment in juvenile blacktip sharks Carcharhinus limbatus

“…The increases in metabolic rate and decreases in swimming efficiency found here for tagged C. limbatus are generally mirrored by past studies in sharks and teleosts, where tagging has resulted in increased metabolic rates (Burgerhout et al ., ; Lowe et al ., ; Methling et al ., ; Steinhausen et al ., ), increased B T frequency (Bouyoucos et al ., ; Methling et al ., ) and decreased swimming speeds and stride length (Bouyoucos et al ., ; Counihan & Frost, ; Janak et al ., ; Methling et al ., ; Steinhausen et al ., ) in fish carrying externally attached tags compared with control animals. These changes in swimming efficiency with tagging are generally attributed to two main factors: first, that externally attached tags impose increased drag on animals as they swim; second, that the tags increase the negative buoyancy of fish.…”

“…However, several studies have shown that effects of tagging can still be observed within, or near, this body-mass-tag ratio (reviewed by Bridger & Booth, 2003;Jepson et al, 2005). For example in elasmobranchs, increased energy costs have been reported in scalloped hammerhead sharks Sphyrna lewini (Griffith & Smith 1834) swimming with a tag representing approximately 4% of the body mass of study animals (Lowe et al, 1998) and decreased swimming performance has been shown for lemon sharks Negaprion brevirostris (Poey 1868) carrying tags 1.2-2.4% of their body weight (Bouyoucos et al, 2017b). Conversely, no effects of tagging were observed in juvenile sandbar sharks Carcharhinus plumbeus (Nardo 1827) carrying positively buoyant pop-up satellite archival tags (Lynch et al, 2017).…”

“…For example, Bouyoucos et al (2017b) found that carrying a tag approximately 2.4% body mass changed diel activity patterns in juvenile N. brevirostris. Altered swimming capacity of tagged animals could also result in reduced home range or activity estimates.…”

Meta‐analysis of post‐release fishing mortality in apex predatory pelagic sharks and white marlin

“…spawning, migration, reproduction) for pelagic sharks released from fishing gear but carrying PSATs was probably not detrimental to their health (Jepsen, Thorstad, Havn & Lucas, 2015;Lynch, Marcek, Marshall, Bushnell & Bernal, 2017;Musyl, Domeier et al, 2011). Should PSATs or other tags remain attached for prolonged periods, the possibility exists that extra drag and energetic costs could affect long-term fitness and health outcomes (Bouyoucos, Montgomery, Brownscombe, Cooke & Suski, 2017;Bouyoucos, Suski, Mandelman & Brooks, 2017;Lear, Gleiss & Whitney, 2018), but there was no evidence of increased mortality with time-to-event and the bulk of F r occurred within 40 days of release. Finally, Guida (2016) and Wosnick et al (2019) demonstrated population-level effects in small rays and sharks exposed to fishing, but it remains unresolved whether these findings can be extrapolated to other pelagic elasmobranchs.…”

Ethical considerations in fish research

“…There are a variety of different factors that will determine the type of tag used and individual validation studies are important for determining whether the intended tag is suitable for the target animal. Validation studies are typically designed to observe the effects of tags on swimming kinematics, swimming performance, energy expenditure (measured as oxygen uptake rates) while swimming or at rest, behaviour, or survivorship (Bouyoucos et al ., ; Lefrançois et al ., ; Lowe, ; Makiguchi & Ueda, ; Ross & McCormick, ). It is unclear, however, what constitutes an acceptable level of impairment to the aforementioned metrics due to tagging.…”