Acoustic tracking of the dispersal of organic matter by scavenging fishes in the deep-sea

Movements of the scavenging deep-sea fish Coryphaenoides (Nematonurus) armatus were tracked at depths of 2500–4800 m on the Porcupine Abyssal Plain and Porcupine Seabight in the NE Atlantic using the Aberdeen University Deep Ocean Submersible (AUDOS). The AUDOS was deployed with mackerel bait and three coded acoustic transponders (CATs) covered in mackerel flesh and each enclosed in a nylon bag. Time lapse photographs allowed identification of fish ingesting CATs and estimation of fish arrival times and staying times at the bait. The radial swimming speeds recorded were much slower than inferred in previous studies using older designs of tracking equipment.