Acoustic detection and tracking of abyssopelagic animals: description of an autonomous split-beam acoustic array

Long-Term Change in Benthopelagic Fish Abundance in the Abyssal Northeast Pacific Ocean

“…Only fish close to the seabed (Ͻ2 m above bottom) were visible to the camera. Coryphaenoides armatus, although a predominantly demersal species, does engage in excursions above the seafloor (Smith et al 1989). The proportion of the time spent above the bottom by grenadiers during normal activity is not well known, but acoustic tracking studies at a nearby station indicated that grenadiers left the seafloor for less than 5% of the time (Priede et al 1990).…”

Deep‐Sea Benthic Sampling

“…This can be achieved by either a modified Ekman grab mechanism (e.g. Smith's Free Vehicle Grab Respirometer, FVGR, see Smith & White, 1982), or by a more sophisticated mechanism utilising a spring-driven assembly and hydraulic cylinder (to be pressurised before deployment). A scoop can be rotated through the sediment to activate the lid closure, sealing the chamber top and bottom, as described by Jahnke and Christiansen (1989).…”

“…Thurston et al, 1995). The elegant approach of getting scavenging fish that are attracted to bait to swallow acoustic tags, and to subsequently track their movement using ranging sonar emplaced at the bottom, is now quite well developed (Smith et al, 1989;Bagley et al, 1990;Priede et al, 1994), and can be seen as one way to sample the community, even if it is restricted to large motile scavengers able to ingest acoustic tags. The utility of emerging technology based on the analysis of acoustic backscatter has also been tested for monitoring the activity of larger animals over the sediment, with promising results (Jumars et al, 1996).…”

Technology Workshop for a Census of Marine Life

“…comm) and baited fish traps with gill nets (Smith et al, 1979) are also viable instruments for collecting deep-sea fishes. Remote monitoring of deep-sea fishes using moored acoustical arrays (vertically profiling and side scanning) has revealed very large targets not collected in concurrently set trawls and baited traps at abyssal depths (Smith et al, 1989;Smith et al, 1992). Acoustic tagging of scavenging fishes on the sea floor has been successful in monitoring population dynamics of selected species (Priede and Smith, 1986).…”