A visual survey technique for deep-water fishes: estimating anglerfish Lophius spp. abundance in closed areas

F. D. McIntyre*, N. Collie, M. Stewart, L. Scala, P. G. Fernandes

*Corresponding author for this work

Research output: Contribution to journalArticle

8 Citations (Scopus)

Abstract

A visual survey technique was employed to estimate the abundance and distribution of anglerfish Lophius spp. in areas where destructive sampling methods, such as trawling, are unacceptable. To enable visual surveying at depths of over 300m, a deep towed vehicle was developed equipped with video, lights and other sensors and was towed at speeds of up to 15ms(-1) and altitudes of up to 10m (from the seabed) to survey large areas of the seabed around the Rockall Bank in the north-west Atlantic Ocean. The system allowed for areas up to 125 000m(2) to be surveyed, a substantial area comparable to that surveyed by demersal-trawl sampling. Lophius spp. densities ranged from 15 to 736 fish km(-2); these are comparable to estimated Lophius spp. densities determined by trawl surveys in adjacent areas. Estimates of Lophius spp. abundance in the closed areas ranged between 99 855 and 176 887 for the time series considered (2007-2011).

Original languageEnglish
Pages (from-to)739-753
Number of pages15
JournalJournal of Fish Biology
Volume83
Issue number4
Early online date21 May 2013
DOIs
Publication statusPublished - Oct 2013

Keywords

  • deep-towed system
  • image analysis
  • underwater video
  • lobster nephrops-norvegicus
  • Norway lobster
  • towed camera
  • underwater television
  • sampling techniques
  • Northeast Pacific
  • stock assessment
  • megafauna
  • assemblages
  • disturbance

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