Behavioral Energetics of the Juvenile Lemon Shark

The lemon shark (Negaprion brevirostris) is given “vulnerable” status (IUCN, 2020), and is found in the Atlantic and Pacific Oceans. I worked with juvenile lemon sharks in Bimini, Bahamas collecting data for my PhD.  It makes an excellent experimental subject as it shows low stress and mortality during capture, is hardy in captivity and exhibits high site fidelity as juveniles, aiding the retrieval of bio-logging tools. I used an accelerometer, pressure and temperature tag to determine the field metabolic rate (FMR) and activity budget of the juvenile lemon shark. My PhD focused on the following major objectives:

1) identify emerging techniques for improving estimates of FMR in fish;

2) calibrate the relationship between oxygen consumption and overall dynamic body acceleration (ODBA)—a metric derived from accelerometers—also accounting for temperature;

3) develop and evaluate a method for classifying behaviour from ADL data;

4) determine seasonal FMR and activity budget;

5) identify the mechanism for intra-annual changes in growth rate;

6) investigate the influence of abiotic variables on behaviour.

A juvenile lemon shark equipped with a tri-axial accelerometer, temperature and pressure tag, coupled with an acoustic transmitter on top.

A 24-h time-energy budget derived for the same shark in the cold dry season (left) and the warm wet-season (right) representing:

(a) sway acceleration

(b) overall dynamic body acceleration (ODBA) obtained from the sum of absolute dynamic acceleration, and temperature recorded by the accelerometer package

(c) mass-specific oxygen consumption (ṀO₂)

(d) behavioral classification of swimming, resting, headshaking and burst swimming