Correlations of metabolic rate and body acceleration in three species of coastal sharks under contrasting temperature regimes

Abstract

The ability to produce estimates of the metabolic rate of free-ranging animals is fundamental to the study of their ecology. However, measuring the energy expenditure of animals in the field has proved difficult, especially for aquatic taxa. Accelerometry presents a means of translating metabolic rates measured in the laboratory to individuals studied in the field, pending appropriate laboratory calibrations. Such calibrations have only been performed on a few fish species to date, and only one where the effects of temperature were accounted for. Here, we present calibrations between activity, measured as overall dynamic body acceleration (ODBA), and metabolic rate, measured through respirometry, for nurse sharks (Ginglymostoma cirratum), lemon sharks (Negaprion brevirostris) and blacktip sharks (Carcharhinus limbatus). Calibrations were made at a range of volitional swimming speeds and experimental temperatures. Linear mixed models were used to determine a predictive equation for metabolic rate based on measured ODBA values, with the optimal model using ODBA in combination with activity state and temperature to predict metabolic rate in lemon and nurse sharks, and ODBA and temperature to predict metabolic rate in blacktip sharks. This study lays the groundwork for calculating the metabolic rate of these species in the wild using acceleration data.

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

“…Respirometry trials were conducted in a closed static respirometer with a diameter of 2.45 m and a volume of 2,494 l, with the system described in detail in Lear et al . () and Whitney et al . ().…”

“…For each analysis period, a linear regression was run through all DO measurements made during the interval and the slope of this regression line (the oxygen degradation curve) was used to calculate oxygen consumption rate ( Ṁ O 2, mgO 2 kg −1 hr −1 ) using Equation 1 in Lear et al . (). All oxygen degradation curves with R 2 > 0.95 were used to calculate Ṁ O 2 .…”

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

“…Furthermore, N . brevirostris have proven to be effective study subjects for validating the use of accelerometry for behavioural and energetics studies of sharks (Shepard et al ., 2008 a , b ; Gleiss et al ., ; Bullock et al ., ; Wilson et al ., ; Lear et al ., ; Bouyoucos et al ., ).…”

“…Miniaturized acceleration biologgers (accelerometers) were selected as the external telemetry package because accelerometers are becoming popular among fish telemetry studies (Brown et al, 2013;Metcalfe et al, 2016) with few validation studies to date (Bullock et al, 2015). Furthermore, N. brevirostris have proven to be effective study subjects for validating the use of accelerometry for behavioural and energetics studies of sharks (Shepard et al, 2008a, b;Gleiss et al, 2009;Bullock et al, 2015;Wilson et al, 2015;Lear et al, 2016;Bouyoucos et al, 2017).…”

Temporal and spatial activity‐associated energy partitioning in free‐swimming sea snakes

“…Shepard et al 2008;Moreau et al 2009;Whitney et al 2010;Brown et al 2013). However, if this technique is to be used to understand longer term energy partitioning of wild animals over seasonal cycles and/or in thermally variable environments, calibration models must incorporate the influence of temperature on the relationship between acceleration and _ Vo 2 , and temperature must be monitored during the collection of acceleration data in the field (Lear et al 2016).…”