Changes in the structure and functionof the North Sea fish foodweb, 1973-2000, and the impacts of fishing and climate

Michael R. Heath, Scottish Executive Environment (Funder), Rural Affairs Department (Funder)

Research output: Contribution to journalArticle

119 Citations (Scopus)

Abstract

North Sea environmental and biological data were analysed to examine 30-year changes in production and consumption in the fish food web. The analysis revealed that the demand for secondary production placed on the ecosystem by fish declined from approximately 20 g Cm-2 y-1 in the 1970s to 16 g C m-2 y-1 in the 1990s. Over the same period, the proportion of demand provided by zooplankton production increased from around 70% to 75%. The overall decrease was mainly due to a reduction in piscivorous demersal fish. Average secondary production by omnivorous zooplankton was estimated to be 35 g Cm-2 y-1, and annual fluctuations were positively correlated with the gross production of planktivorous fish. The results suggest a ''bottom-up'' control of the pelagic foodweb. Individual planktivore species have been impacted by fishing, but the populations of other functionally similar species have expanded to fill the vacant niches, thus maintaining the planktivore role in the system. In contrast, the results indicate that benthos production was more "top-down" controlled. Overall, demersal fish species have been depleted by fishing, with no obvious species expansions to fill the vacant niche, releasing the benthos from predation pressure, and leading to an increase in benthic production and fisheries for invertebrates.
LanguageEnglish
Pages847-868
Number of pages21
JournalICES Journal of Marine Science
Volume62
Issue number5
DOIs
Publication statusPublished - 1 Jan 2005

Fingerprint

secondary productivity
fish production
benthic organisms
North Sea
marine fish
zooplankton
fishing
niches
climate
planktivore
fish consumption
demersal fish
secondary production
fish
food webs
benthos
niche
invertebrates
fisheries
predation

Keywords

  • benthos
  • demersal fish
  • fish diet
  • fisheries
  • food consumption
  • pelagic fish
  • plankton
  • production
  • stock assessment

Cite this

Heath, Michael R. ; Scottish Executive Environment (Funder) ; Rural Affairs Department (Funder). / Changes in the structure and functionof the North Sea fish foodweb, 1973-2000, and the impacts of fishing and climate. In: ICES Journal of Marine Science. 2005 ; Vol. 62, No. 5. pp. 847-868.
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Changes in the structure and functionof the North Sea fish foodweb, 1973-2000, and the impacts of fishing and climate. / Heath, Michael R.; Scottish Executive Environment (Funder); Rural Affairs Department (Funder).

In: ICES Journal of Marine Science, Vol. 62, No. 5, 01.01.2005, p. 847-868.

Research output: Contribution to journalArticle

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