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Institute of Marine Research

Barents Sea Northeast Arctic cod bottom trawl index in winter

Recommended citation:
Sigbjørn Mehl, Bjarte Bogstad (2019) Barents Sea Northeast Arctic cod bottom trawl index in winter
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Abstract
This is a parent site of all data sets for Barents Sea Northeast Arctic cod bottom trawl index in winter over several years. It contains the latest data set and links to previous versions. The survey indices by age group for bottom trawl and acoustic estimates for cod from the winter survey (January-March) in the Barents Sea are calculated as described in Mehl et al. 2016 (bottom trawl) and Mehl et al. 2018 (acoustic). Mean length and weight at age is also calculated. Updated data series are provided in the annual survey reports (e.g. Mehl et al. 2019). The series go back to 1981, but StoX estimates go back only to 1994. The survey has been a Joint Norwegian-Russian one from 2000 onwards except in the years 2006, 2007 and 2017. The survey area is divided into eight main areas and 26 strata. In 2014, the investigated area was enlarged by three new strata in northwest, 24-26. These strata are, however, not included in the standard calculations of indices. Note also that prior to 1994, the area covered was smaller and no adjustments have been made for that. In the early period (1981-1995) there were also some gear changes, for which adjustments have been made, these changes are also described in the reports referred to. In 1997, 1998 and 2007 only the Norwegian EEZ (NEZ) and parts of the Svalbard area (S) was covered. The indices for cod and haddock have therefore been raised to also represent the Russian EEZ (REZ) (Mehl et al. 2016, 2018). In 2006, there was not a complete coverage in southeast due to restrictions. The observations in the partially covered strata 7 were extrapolated to the full strata, and the observations in the partially covered strata 13 were extrapolated to the same area as covered in 2005. In 2012 the coverage was incomplete in the eastern areas, and the cod and haddock swept area estimates within the covered area were raised by the “index ratio by age” observed for the same area in 2008-2011 (ICES 2012). The scaling factor (“index ratio”) for estimating adjusted total from <Total – area D’> was the average ratio by age for Total/(Total – area D’) in the years 2008-2011 (Aglen et al. 2012). In 2017, the Norwegian vessel was not allowed to operate south of 70º 10’ N and west of 41º 00 º E, and no Russian vessel participated in the survey. Only a small part of strata 7 was covered, and strata 13, 15, 17 and 20 were not covered. The cod, haddock, Greenland halibut and beaked redfish swept area estimates and cod and haddock acoustic estimates within the covered area were raised following the same procedure as for 2012. The scaling factor for estimating adjusted total from <Total –strata 7 > was the average ratio by age for Total/(Total – (strata 7+13+15+17+20)) swept area indices in the years 2014-2016. All these adjustments are included in the StoX projects used for the calculations.
Scientific keywords:
EARTH SCIENCE> BIOLOGICAL CLASSIFICATION> ANIMALS/VERTEBRATES> FISH> RAY-FINNED FISHES> CODS/HADDOCKS
Key words:
Cod, IMR Monitoring series
Data downloads
Type Description URL
VIEW RELATED INFORMATION Mehl et al. 2016 https://www.hi.no/resources/publikasjoner/fisken-og-havet/2016/fh_10-2016_stox_revision_of_the_swept_area_abundance_indices_1994-2016_pdf_print.pdf
VIEW RELATED INFORMATION Johnsen et al. 2019 https://doi.org/10.1111/2041-210X.13250
PREVIOUS VERSION 1994 v.1 http://metadata.nmdc.no/metadata-api/landingpage/61458c9dc7a352069a057aaf1e8d32ed
PREVIOUS VERSION 1995 v.1 http://metadata.nmdc.no/metadata-api/landingpage/c8dffae7a8bb947333ca5deef7f90d8a
PREVIOUS VERSION 1996 v.1 http://metadata.nmdc.no/metadata-api/landingpage/3eb6ffe6ece799fd7ff6b80b3284170e
PREVIOUS VERSION 1999 v.1 http://metadata.nmdc.no/metadata-api/landingpage/1b9c24073cee5ab788dc24381374ec3a
PREVIOUS VERSION 2000 v.1 http://metadata.nmdc.no/metadata-api/landingpage/c1d63d5a071c9da816b9c8ac2fdf31f7
PREVIOUS VERSION 2001 v.1 http://metadata.nmdc.no/metadata-api/landingpage/855d891eef77321a70ec11673f7b4617
PREVIOUS VERSION 2002 v.1 http://metadata.nmdc.no/metadata-api/landingpage/19188c96605eafd1cbaf62785d26ccdf
PREVIOUS VERSION 2003 v.1 http://metadata.nmdc.no/metadata-api/landingpage/784967d45902570c4e4f9d79165b1a03
PREVIOUS VERSION 2004 v.1 http://metadata.nmdc.no/metadata-api/landingpage/ddbbcf502c286e270dfa558646a077cb
PREVIOUS VERSION 2005 v.1 http://metadata.nmdc.no/metadata-api/landingpage/070b2ee67192bbbe72309b6bc846e4cb
PREVIOUS VERSION 2008 v.1 http://metadata.nmdc.no/metadata-api/landingpage/a3169869531eb3713f6d27a47fa8ec34
PREVIOUS VERSION 2009 v.1 http://metadata.nmdc.no/metadata-api/landingpage/5619179c5299b8604e7600ed2bdaaf2e
PREVIOUS VERSION 2010 v.1 http://metadata.nmdc.no/metadata-api/landingpage/1ed4a7d053391616257e680bc28ee726
PREVIOUS VERSION 2011 v.1 http://metadata.nmdc.no/metadata-api/landingpage/51300f76e4ba78af886c97dfe8df6e2a
PREVIOUS VERSION 2013 v.1 http://metadata.nmdc.no/metadata-api/landingpage/980091e21dd2b15fe0fc6c13a75f963e
PREVIOUS VERSION 2014 v.1 http://metadata.nmdc.no/metadata-api/landingpage/132b73ae416b6b7356dcfcd317295619
PREVIOUS VERSION 2015 v.1 http://metadata.nmdc.no/metadata-api/landingpage/32001308bc30bf0d402e402d3d67a48e
PREVIOUS VERSION 2016 v.1 http://metadata.nmdc.no/metadata-api/landingpage/8059722ac06316cb83340ff084a5375a
PREVIOUS VERSION 2019 v.1 http://metadata.nmdc.no/metadata-api/landingpage/4fe502f43b5bd1155643f08b2025f817
PREVIOUS VERSION 2018 v.1 http://metadata.nmdc.no/metadata-api/landingpage/703e12e9e6cb0d8db2926bf83f7a2fa9
GET DATA StoX folder https://ftp.nmdc.no/nmdc/IMR/surveytimeseries/Barents+Sea+Northeast+Arctic+cod+bottom+trawl+index+in+winter/Cod_2019_1.zip
PREVIOUS VERSION 1997 v.1 http://metadata.nmdc.no/metadata-api/landingpage/1ff5d19295607072794f416d3c209f53
PREVIOUS VERSION 1998 v.1 http://metadata.nmdc.no/metadata-api/landingpage/acb8292e282c0871e8e1ffc8fa9ef6ca
PREVIOUS VERSION 2006 v.1 http://metadata.nmdc.no/metadata-api/landingpage/3c5aef7cf2d79e4015945ee442c18212
PREVIOUS VERSION 2007 v.1 http://metadata.nmdc.no/metadata-api/landingpage/4e39b630c0a85b75412a548af6e84210
PREVIOUS VERSION 2012 v.1 http://metadata.nmdc.no/metadata-api/landingpage/66829efd895c122c93f9185f0c1bfef5
PREVIOUS VERSION 2017 v.1 http://metadata.nmdc.no/metadata-api/landingpage/5469650a026513138c260c6f4065cdc9
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4abaafc79163a4ffed0b2ec7f2aca002.xml
No Spatial coverage