Deepwater observations of monkfish, Lophius piscatorius, in the Northeastern Atlantic Ocean by means of a remotely operated vehicle

In situ behaviour of anglerfish Lophius piscatorius was observed by a remotely operated vehicle (ROV) in the vicinity of the Schiehallion oil field to the west of the Shetland Isles, Scotland at water depths c. 350 m. Several behaviour patterns associated with the 'sit-and-wait' feeding strategy of L. piscatorius were identified and are described. Concealment behaviour was characterized by recess creation using pectoral and pelvic fins. Sit-and-wait and resting behaviour was typified by relaxed dorsal fin rays and a 34 s exhalation rate. Prey detection responses had a range of c. 5 m and were identified by erection of the fin rays and a reduction in the exhalation rate to once every 65 s. Prey attraction was characterized by lure (illicia) casting, erect dorsal rays and was dependant on both the proximity and position of potential prey. An opportunistic feeding attack is also described. Walking behaviour was also recorded and is described.