Spatial and temporal trends in species richness and abundance for southerly and northerly components of the North Sea fish community separately, based on IBTS data 197702005

N. Daan

Research output: Contribution to conferencePaperAcademic

Abstract

Based on the North Sea International Bottom Trawl Survey, the number of species recorded after 20 hauls is used as an index of biodiversity at a spatial scale of 10*10nm. The results show a clear pattern: species richness is lowest in the central North Sea and highest in Scottish waters, in the Kattegat and in the Channel area. When the community is split into its northerly and southerly components, the former reaches its highest diversity in waters typically deeper than 100m and the latter in waters less than 50m. The area of high richness of northerly species extends from Scottish waters along the Norwegian trench into the Kattegat. High richness of southerly species is not restricted to the southern North Sea but is observed also along the Scottish coast and in the Kattegat. These patterns are discussed in relation to hydrographical features that may control these differences. Temporal trends indicate that both components are characterized by a gradual increase in species richness over the past 25 years, a process that has affected the whole area while rates of change did hardly differ between the components or areas. A standardized index of abundance also indicates long-term gradual increases for both northerly and southerly species, although in this case the increase in southern species is larger. I argue that overexploitation is a more plausible explanation for the observed phenomena, although climate change may have had add-on effects.
Original languageEnglish
Number of pages10
Publication statusPublished - 2006
EventICES Annual Science Conference 2006, Maastricht, 19-23 September 2006 -
Duration: 19 Sep 200623 Sep 2006

Conference

ConferenceICES Annual Science Conference 2006, Maastricht, 19-23 September 2006
Period19/09/0623/09/06

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species richness
fish
bottom trawling
water
trench
deep water
trend
sea
biodiversity
climate change
coast
index

Keywords

  • fishes
  • species diversity
  • climatic change
  • marine areas
  • north sea

Cite this

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title = "Spatial and temporal trends in species richness and abundance for southerly and northerly components of the North Sea fish community separately, based on IBTS data 197702005",
abstract = "Based on the North Sea International Bottom Trawl Survey, the number of species recorded after 20 hauls is used as an index of biodiversity at a spatial scale of 10*10nm. The results show a clear pattern: species richness is lowest in the central North Sea and highest in Scottish waters, in the Kattegat and in the Channel area. When the community is split into its northerly and southerly components, the former reaches its highest diversity in waters typically deeper than 100m and the latter in waters less than 50m. The area of high richness of northerly species extends from Scottish waters along the Norwegian trench into the Kattegat. High richness of southerly species is not restricted to the southern North Sea but is observed also along the Scottish coast and in the Kattegat. These patterns are discussed in relation to hydrographical features that may control these differences. Temporal trends indicate that both components are characterized by a gradual increase in species richness over the past 25 years, a process that has affected the whole area while rates of change did hardly differ between the components or areas. A standardized index of abundance also indicates long-term gradual increases for both northerly and southerly species, although in this case the increase in southern species is larger. I argue that overexploitation is a more plausible explanation for the observed phenomena, although climate change may have had add-on effects.",
keywords = "vissen, soortendiversiteit, klimaatverandering, mariene gebieden, noordzee, fishes, species diversity, climatic change, marine areas, north sea",
author = "N. Daan",
year = "2006",
language = "English",
note = "ICES Annual Science Conference 2006, Maastricht, 19-23 September 2006 ; Conference date: 19-09-2006 Through 23-09-2006",

}

Daan, N 2006, 'Spatial and temporal trends in species richness and abundance for southerly and northerly components of the North Sea fish community separately, based on IBTS data 197702005' Paper presented at ICES Annual Science Conference 2006, Maastricht, 19-23 September 2006, 19/09/06 - 23/09/06, .

Spatial and temporal trends in species richness and abundance for southerly and northerly components of the North Sea fish community separately, based on IBTS data 197702005. / Daan, N.

2006. Paper presented at ICES Annual Science Conference 2006, Maastricht, 19-23 September 2006, .

Research output: Contribution to conferencePaperAcademic

TY - CONF

T1 - Spatial and temporal trends in species richness and abundance for southerly and northerly components of the North Sea fish community separately, based on IBTS data 197702005

AU - Daan, N.

PY - 2006

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N2 - Based on the North Sea International Bottom Trawl Survey, the number of species recorded after 20 hauls is used as an index of biodiversity at a spatial scale of 10*10nm. The results show a clear pattern: species richness is lowest in the central North Sea and highest in Scottish waters, in the Kattegat and in the Channel area. When the community is split into its northerly and southerly components, the former reaches its highest diversity in waters typically deeper than 100m and the latter in waters less than 50m. The area of high richness of northerly species extends from Scottish waters along the Norwegian trench into the Kattegat. High richness of southerly species is not restricted to the southern North Sea but is observed also along the Scottish coast and in the Kattegat. These patterns are discussed in relation to hydrographical features that may control these differences. Temporal trends indicate that both components are characterized by a gradual increase in species richness over the past 25 years, a process that has affected the whole area while rates of change did hardly differ between the components or areas. A standardized index of abundance also indicates long-term gradual increases for both northerly and southerly species, although in this case the increase in southern species is larger. I argue that overexploitation is a more plausible explanation for the observed phenomena, although climate change may have had add-on effects.

AB - Based on the North Sea International Bottom Trawl Survey, the number of species recorded after 20 hauls is used as an index of biodiversity at a spatial scale of 10*10nm. The results show a clear pattern: species richness is lowest in the central North Sea and highest in Scottish waters, in the Kattegat and in the Channel area. When the community is split into its northerly and southerly components, the former reaches its highest diversity in waters typically deeper than 100m and the latter in waters less than 50m. The area of high richness of northerly species extends from Scottish waters along the Norwegian trench into the Kattegat. High richness of southerly species is not restricted to the southern North Sea but is observed also along the Scottish coast and in the Kattegat. These patterns are discussed in relation to hydrographical features that may control these differences. Temporal trends indicate that both components are characterized by a gradual increase in species richness over the past 25 years, a process that has affected the whole area while rates of change did hardly differ between the components or areas. A standardized index of abundance also indicates long-term gradual increases for both northerly and southerly species, although in this case the increase in southern species is larger. I argue that overexploitation is a more plausible explanation for the observed phenomena, although climate change may have had add-on effects.

KW - vissen

KW - soortendiversiteit

KW - klimaatverandering

KW - mariene gebieden

KW - noordzee

KW - fishes

KW - species diversity

KW - climatic change

KW - marine areas

KW - north sea

M3 - Paper

ER -