Using autonomous video to estimate the bottom-contact area of longline trap gear and presence–absence of sensitive benthic habitat1

Bottom longline hook and trap fishing gear can potentially damage sensitive benthic areas (SBAs) in the ocean; however, the large-scale risks to these habitats are poorly understood because of the difficulties in mapping SBAs and in measuring the bottom-contact area of longline gear. In this paper,...

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Bibliographic Details
Published in:Canadian journal of fisheries and aquatic sciences 2018, Vol.75 (5), p.797-812
Main Authors: Doherty, Beau, Johnson, Samuel D.N, Cox, Sean P
Format: Article
Language:English
Online Access:Get full text
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Summary:Bottom longline hook and trap fishing gear can potentially damage sensitive benthic areas (SBAs) in the ocean; however, the large-scale risks to these habitats are poorly understood because of the difficulties in mapping SBAs and in measuring the bottom-contact area of longline gear. In this paper, we describe a collaborative academic–industry–government approach to obtaining direct presence–absence data for SBAs and to measuring gear interactions with seafloor habitats via a novel deepwater trap camera and motion-sensing systems on commercial longline traps for sablefish (Anoplopoma fimbria) within S G aan K inghlas – Bowie Seamount Marine Protected Area. We obtained direct presence–absence observations of cold-water corals (Alcyonacea, Antipatharia, Pennatulacea, Stylasteridae) and sponges (Hexactinellida, Demospongiae) at 92 locations over three commercial fishing trips. Video, accelerometer, and depth sensor data were used to estimate a mean bottom footprint of 53 m 2 for a standard sablefish trap, which translates to 3200 m 2 (95% CI = 2400–3900 m 2 ) for a 60-trap commercial sablefish longline set. Our successful collaboration demonstrates how research partnerships with commercial fisheries have potential for massive improvements in the quantity and quality of data needed for conducting SBA risk assessments over large spatial and temporal scales.
ISSN:0706-652X
1205-7533
DOI:10.1139/cjfas-2016-0483