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UK Biodiversity Indicators 2019. Indicator D1a – Fish size classes 2019

Corporate UK Biodiversity


These documents support response indicator: D1a. Fish size classes in the North Sea. The documents include a fiche and datasheet. Technical documentation for the indicator is available from

The indicator shows changes in the proportion, by weight, of large individuals equal to or over 50cm in length in demersal (bottom-dwelling) fish populations in the North Sea. Changes in the size structure of fish populations and communities reflect changes in the state of the fish community. Fluctuations in values between years are expected given inter-annual fluctuations in the distribution and abundance of North Sea fish populations and sampling variation.

Resource type Publication

Topic category Environment

Reference date 2019·09·05

Department for Environment, Food and Rural Affairs, UK (2019). UK Biodiversity Indicators 2019.

The UK indicators were comprehensively reviewed during 2011 and 2012 to ensure they continued to be based on the most robust and reliable available data; and remained relevant to the new international goals and targets. Since then the indicators have been refined to improve their relevance/quality, and new indicators developed to fill gaps. In this version of the publication as many as possible of the indicators have been updated with new data. In some cases, however, development work is ongoing, and where this is the case, the work to develop them has been described briefly.

Responsible organisation
Communications, JNCC distributor

Limitations on public access No limitations

Use constraints Released under the Open Government Licence v3.0. Attribution statement "Contains public sector information from Defra, licenced under the Open Government Licence v3.0"

Metadata date 2019·09·05

Metadata point of contact
Communications, JNCC

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