title: High resolution study of the spatial distributions of abyssal fishes by autonomous underwater vehicle.
abstract: On abyssal plains, demersal fish are believed to play an important role in transferring energy across the seafloor and between the pelagic and benthic realms. However, little is known about their spatial distributions, making it difficult to quantify their ecological significance. To address this, we employed an autonomous underwater vehicle to conduct an exceptionally large photographic survey of fish distributions on the Porcupine Abyssal Plain (NE Atlantic, 4850 m water depth) encompassing two spatial scales (1-10 km(2)) on and adjacent to a small abyssal hill (240 m elevation). The spatial distributions of the total fish fauna and that of the two dominant morphotypes (Coryphaenoides sp. 1 and C. profundicolus) appeared to be random, a result contrary to common expectation but consistent with previous predictions for these fishes. We estimated total fish density on the abyssal plain to be 723 individuals km(-2) (95% CI: 601-844). This estimate is higher, and likely more precise, than prior estimates from trawl catch and baited camera techniques (152 and 188 individuals km(-2) respectively). We detected no significant difference in fish density between abyssal hill and plain, nor did we detect any evidence for the existence of fish aggregations at any spatial scale assessed.
authors.affiliation: Halmos College of Natural Sciences and Oceanography, NOVA Southeastern University, 8000 North Ocean Drive, Dania Beach, Florida, 33004, USA.|Institute of Biodiversity, Animal Health and Comparative Medicine, Graham Kerr Building, University of Glasgow, Glasgow, G12 8QQ, UK.
authors.forename: R J
authors.initials: RJ
authors.lastname: Milligan
authors.affiliation: National Oceanography Centre Southampton, University of Southampton Waterfront Campus, European Way, Southampton, SO14 3ZH, UK.
authors.forename: K J
authors.initials: KJ
authors.lastname: Morris
authors.affiliation: National Oceanography Centre Southampton, University of Southampton Waterfront Campus, European Way, Southampton, SO14 3ZH, UK.
authors.forename: B J
authors.initials: BJ
authors.lastname: Bett
authors.affiliation: National Oceanography Centre Southampton, University of Southampton Waterfront Campus, European Way, Southampton, SO14 3ZH, UK.|Ocean and Earth Science, University of Southampton, National Oceanography Centre, University of Southampton Waterfront Campus, European Way, Southampton, SO14 3ZH, UK.
authors.forename: J M
authors.initials: JM
authors.lastname: Durden
authors.affiliation: National Oceanography Centre Southampton, University of Southampton Waterfront Campus, European Way, Southampton, SO14 3ZH, UK.
authors.forename: D O B
authors.initials: DO
authors.lastname: Jones
authors.affiliation: National Oceanography Centre Southampton, University of Southampton Waterfront Campus, European Way, Southampton, SO14 3ZH, UK.|Ocean and Earth Science, University of Southampton, National Oceanography Centre, University of Southampton Waterfront Campus, European Way, Southampton, SO14 3ZH, UK.
authors.forename: K
authors.initials: K
authors.lastname: Robert
authors.affiliation: National Oceanography Centre Southampton, University of Southampton Waterfront Campus, European Way, Southampton, SO14 3ZH, UK.
authors.forename: H A
authors.initials: HA
authors.lastname: Ruhl
authors.affiliation: Institute of Biodiversity, Animal Health and Comparative Medicine, Graham Kerr Building, University of Glasgow, Glasgow, G12 8QQ, UK.
authors.forename: D M
authors.initials: DM
authors.lastname: Bailey
mesh_terms: D000818:Animals; D044822:Biodiversity; D017753:Ecosystem; D048388:Gadiformes / Q000502:physiology*; D008386:Marine Biology; D009792:Oceans and Seas; D010781:Photography; D011795:Surveys and Questionnaires