Putative fishery-induced changes in biomass and population size structures of demersal deep-sea fishes in ICES Sub-area VII, Northeast Atlantic Ocean

J. A. Godbold*, D. M. Bailey, M. A. Collins, J. D. M. Gordon, W. A. Spallek, I. G. Priede

*Corresponding author for this work

Research output: Contribution to journalArticle

10 Citations (Scopus)
4 Downloads (Pure)

Abstract

A time series from 1977-1989 and 2000-2002 of scientific trawl surveys in the Porcupine Seabight and adjacent abyssal plain of the NE Atlantic was analysed to assess changes in demersal fish biomass and length frequency. These two periods coincide with the onset of the commercial deep-water fishery in the late 1970s and the onset of the regulation of the fishery in the early 2000's, which allowed us to investigate changes in the relationship between total demersal fish biomass and depth between the pre- and post commercial fishing periods, as well as changes in the biomass (kg km(-2)) depth distribution and length frequency distribution of the most dominant fish species. Our results show a decline in total demersal fish biomass of 36% within the depth range of the commercial fishery (<1500 m). Whilst there were significant declines in target (e.g. Coryphaenoides rupestris decreased by 57 %) and non-target (e.g. C. guentheri and Antimora rostrata) species, not all species declined significantly. Changes in the overall length-frequency distribution were detected for 5 out of the 8 dominant species occupying depth ranges both within and outside the maximum depth for commercial trawling. This suggests that whilst there is evidence for likely fishery impacts on the biomass distribution of the demersal fish population as a whole, species-specific impacts are highly variable. It is clear that changes in population structure can extend beyond the depth at which fishing takes place, highlighting the importance for also considering the indirect effects on deep-sea fish populations.

Original languageEnglish
Pages (from-to)529-539
Number of pages11
JournalBiogeosciences
Volume10
Issue number1
DOIs
Publication statusPublished - 25 Jan 2013

Keywords

  • eel synaphobranchus-kaupii
  • porcupine seabight
  • Rockall trough
  • assemblage structure
  • roundnose grenadier
  • continental-slope
  • disturbance
  • ecosystem
  • impacts
  • trawl

Cite this

Putative fishery-induced changes in biomass and population size structures of demersal deep-sea fishes in ICES Sub-area VII, Northeast Atlantic Ocean. / Godbold, J. A.; Bailey, D. M.; Collins, M. A.; Gordon, J. D. M.; Spallek, W. A.; Priede, I. G.

In: Biogeosciences, Vol. 10, No. 1, 25.01.2013, p. 529-539.

Research output: Contribution to journalArticle

Godbold, J. A. ; Bailey, D. M. ; Collins, M. A. ; Gordon, J. D. M. ; Spallek, W. A. ; Priede, I. G. / Putative fishery-induced changes in biomass and population size structures of demersal deep-sea fishes in ICES Sub-area VII, Northeast Atlantic Ocean. In: Biogeosciences. 2013 ; Vol. 10, No. 1. pp. 529-539.
@article{8f4c8b0471ee420686dcabe4240ca39e,
title = "Putative fishery-induced changes in biomass and population size structures of demersal deep-sea fishes in ICES Sub-area VII, Northeast Atlantic Ocean",
abstract = "A time series from 1977-1989 and 2000-2002 of scientific trawl surveys in the Porcupine Seabight and adjacent abyssal plain of the NE Atlantic was analysed to assess changes in demersal fish biomass and length frequency. These two periods coincide with the onset of the commercial deep-water fishery in the late 1970s and the onset of the regulation of the fishery in the early 2000's, which allowed us to investigate changes in the relationship between total demersal fish biomass and depth between the pre- and post commercial fishing periods, as well as changes in the biomass (kg km(-2)) depth distribution and length frequency distribution of the most dominant fish species. Our results show a decline in total demersal fish biomass of 36{\%} within the depth range of the commercial fishery (<1500 m). Whilst there were significant declines in target (e.g. Coryphaenoides rupestris decreased by 57 {\%}) and non-target (e.g. C. guentheri and Antimora rostrata) species, not all species declined significantly. Changes in the overall length-frequency distribution were detected for 5 out of the 8 dominant species occupying depth ranges both within and outside the maximum depth for commercial trawling. This suggests that whilst there is evidence for likely fishery impacts on the biomass distribution of the demersal fish population as a whole, species-specific impacts are highly variable. It is clear that changes in population structure can extend beyond the depth at which fishing takes place, highlighting the importance for also considering the indirect effects on deep-sea fish populations.",
keywords = "eel synaphobranchus-kaupii, porcupine seabight, Rockall trough, assemblage structure, roundnose grenadier, continental-slope, disturbance, ecosystem, impacts, trawl",
author = "Godbold, {J. A.} and Bailey, {D. M.} and Collins, {M. A.} and Gordon, {J. D. M.} and Spallek, {W. A.} and Priede, {I. G.}",
note = "This work was supported by a series of NERC grants to the principal investigators including NE/C512961/1. The results of the early joint SAMS and IOS surveys were digitized with support from EU MAST Contract MAS2-CT920033 1993–1995, and data analyses was supported by EU FP7 Projects HERMES and HERMIONE. We thank Alain Zuur from Highland Statistics Ltd. for advice with the statistical analyses and Odd Aksel Bergstad for valuable comments that helped to improve the manuscript. We thank the ships’ companies of the RRS Challenger and RRS Discovery.",
year = "2013",
month = "1",
day = "25",
doi = "10.5194/bg-10-529-2013",
language = "English",
volume = "10",
pages = "529--539",
journal = "Biogeosciences",
issn = "1726-4170",
publisher = "Copernicus Gesellschaft mbH",
number = "1",

}

TY - JOUR

T1 - Putative fishery-induced changes in biomass and population size structures of demersal deep-sea fishes in ICES Sub-area VII, Northeast Atlantic Ocean

AU - Godbold, J. A.

AU - Bailey, D. M.

AU - Collins, M. A.

AU - Gordon, J. D. M.

AU - Spallek, W. A.

AU - Priede, I. G.

N1 - This work was supported by a series of NERC grants to the principal investigators including NE/C512961/1. The results of the early joint SAMS and IOS surveys were digitized with support from EU MAST Contract MAS2-CT920033 1993–1995, and data analyses was supported by EU FP7 Projects HERMES and HERMIONE. We thank Alain Zuur from Highland Statistics Ltd. for advice with the statistical analyses and Odd Aksel Bergstad for valuable comments that helped to improve the manuscript. We thank the ships’ companies of the RRS Challenger and RRS Discovery.

PY - 2013/1/25

Y1 - 2013/1/25

N2 - A time series from 1977-1989 and 2000-2002 of scientific trawl surveys in the Porcupine Seabight and adjacent abyssal plain of the NE Atlantic was analysed to assess changes in demersal fish biomass and length frequency. These two periods coincide with the onset of the commercial deep-water fishery in the late 1970s and the onset of the regulation of the fishery in the early 2000's, which allowed us to investigate changes in the relationship between total demersal fish biomass and depth between the pre- and post commercial fishing periods, as well as changes in the biomass (kg km(-2)) depth distribution and length frequency distribution of the most dominant fish species. Our results show a decline in total demersal fish biomass of 36% within the depth range of the commercial fishery (<1500 m). Whilst there were significant declines in target (e.g. Coryphaenoides rupestris decreased by 57 %) and non-target (e.g. C. guentheri and Antimora rostrata) species, not all species declined significantly. Changes in the overall length-frequency distribution were detected for 5 out of the 8 dominant species occupying depth ranges both within and outside the maximum depth for commercial trawling. This suggests that whilst there is evidence for likely fishery impacts on the biomass distribution of the demersal fish population as a whole, species-specific impacts are highly variable. It is clear that changes in population structure can extend beyond the depth at which fishing takes place, highlighting the importance for also considering the indirect effects on deep-sea fish populations.

AB - A time series from 1977-1989 and 2000-2002 of scientific trawl surveys in the Porcupine Seabight and adjacent abyssal plain of the NE Atlantic was analysed to assess changes in demersal fish biomass and length frequency. These two periods coincide with the onset of the commercial deep-water fishery in the late 1970s and the onset of the regulation of the fishery in the early 2000's, which allowed us to investigate changes in the relationship between total demersal fish biomass and depth between the pre- and post commercial fishing periods, as well as changes in the biomass (kg km(-2)) depth distribution and length frequency distribution of the most dominant fish species. Our results show a decline in total demersal fish biomass of 36% within the depth range of the commercial fishery (<1500 m). Whilst there were significant declines in target (e.g. Coryphaenoides rupestris decreased by 57 %) and non-target (e.g. C. guentheri and Antimora rostrata) species, not all species declined significantly. Changes in the overall length-frequency distribution were detected for 5 out of the 8 dominant species occupying depth ranges both within and outside the maximum depth for commercial trawling. This suggests that whilst there is evidence for likely fishery impacts on the biomass distribution of the demersal fish population as a whole, species-specific impacts are highly variable. It is clear that changes in population structure can extend beyond the depth at which fishing takes place, highlighting the importance for also considering the indirect effects on deep-sea fish populations.

KW - eel synaphobranchus-kaupii

KW - porcupine seabight

KW - Rockall trough

KW - assemblage structure

KW - roundnose grenadier

KW - continental-slope

KW - disturbance

KW - ecosystem

KW - impacts

KW - trawl

U2 - 10.5194/bg-10-529-2013

DO - 10.5194/bg-10-529-2013

M3 - Article

VL - 10

SP - 529

EP - 539

JO - Biogeosciences

JF - Biogeosciences

SN - 1726-4170

IS - 1

ER -