TY - CONF
TI - Risk balancing by a marine mammal: man-made noise reduces the foraging success of seals
AU - Hastie, G
AU - Lepper, P
AU - McKnight, C
AU - Milne, R
AU - Russell, D
AU - Thompson, D
T2 - World Marine Mammal Conference (WMMC2019)
AB - Foraging theory predicts that individuals should attempt to maximise their energy gain by foraging in patches with high food densities. However, animals faced with a choice between a rewarding food patch which has a high degree of risk associated with it, and one that is both less rewarding but less dangerous, should exhibit foraging decisions that reflect both the degree of risk involved, and the energetic advantage. Sounds from anthropogenic sources can affect marine mammal foraging behaviour, yet evidence of the effects on foraging success in these species is lacking. Here, we measure the influence of anthropogenic sounds (pile driving, a tidal turbine, and a silent control) on grey seal behaviour within a simulated foraging scenario and investigate the influence of food availability and perceived risk. Seals were given access to two underwater 'food patches' in an experimental pool where fish were delivered at controlled rates to simulate a low reward (LR) and a high reward (HR) food patch. Acoustic playbacks were made using an underwater speaker above one of the food patches (randomised during the study), and three foraging metrics (foraging duration, foraging effort allocation between the LR and HR food patches, and foraging success) were measured. Foraging success was highest during silent controls and was similar regardless of speaker location (LR or HR food patch). Under the tidal turbine and pile driving treatments, foraging success was similar to the controls when the speaker was located at the HR food patch but was significantly reduced (~16-28% lower) when the speaker was located at the LR food patch. The results suggest that the foraging decisions by the seals reflect a risk/profit balancing approach. In response to a perceived risk associated with the anthropogenic sounds, seals apparently showed avoidance of the sounds when the energetic rewards were low (speaker at LR food patch) but not when the rewards were high (speaker at HR prey patch).
DA - 2019/09//
PY - 2019
SP - 307
PB - WMMC
UR - https://repository.lboro.ac.uk/articles/Risk_balancing_by_a_marine_mammal_man-made_noise_reduces_the_foraging_success_of_seals_Abstract_/11968107/1
LA - English
KW - Marine Energy
KW - Tidal
KW - Noise
KW - Marine Mammals
KW - Pinnipeds
ER -