Identification

Title

Nephrops underwater TV Surveys in the North Sea (video data and database)

Alternative title(s)

Nephrops burrow counts

Abstract

Underwater TV (UWTV) surveys dataset, used as basis of the Nephrops ( *Nephrops**norvegicus*) assessment to develop fishery independent indicators of stock size, exploitation status and catch advice. The standard methodology involves the use of a sledge mounted camera to film the seabed at a fix grid of stations conducting TV tows for 10 minutes. Data has been collected twice a year between 1997 to 2002 (Spring and Autumn) and once a year since 2003 (autumn). Dataset holds data from two areas of the North Sea (Farn Deeps-FU6 (1996 to 2012) and Botney Gut/Silver Pit-FU5 (2010 to 2012)).

Resource type

dataset

Resource locator

https://data.cefas.co.uk/view/266

name: Cefas Data Portal

description: The Cefas Data Portal contains metadata records and data sets available to download and connect to in support of our commitment to open science.

function: information

Unique resource identifier

code

CEFAS266

codeSpace

https://data.cefas.co.uk

Dataset language

eng

Spatial reference system

code identifying the spatial reference system

Classification of spatial data and services

Topic category

biota

Keywords

Keyword set

keyword value

originating controlled vocabulary

title

reference date

date type

revision

effective date

2011-03-25

Keyword set

keyword value

originating controlled vocabulary

title

reference date

date type

publication

effective date

2008-06-01

Keyword set

keyword value

originating controlled vocabulary

title

reference date

date type

publication

effective date

2008-06-01

Keyword set

keyword value

originating controlled vocabulary

title

reference date

date type

revision

effective date

2010-05-18

Keyword set

keyword value

originating controlled vocabulary

title

reference date

date type

publication

effective date

2012-01-11

Keyword set

keyword value

originating controlled vocabulary

title

reference date

date type

publication

effective date

2012-01-11

Geographic location

West bounding longitude

-1.50

East bounding longitude

4.00

North bounding latitude

55.75

South bounding latitude

53.50

Temporal reference

Temporal extent

Begin position

1996

End position

2012-09-18

Dataset reference date

date type

publication

effective date

2014-06-13

date type

revision

effective date

2023-01-31

date type

creation

effective date

2011-10-07

Frequency of update

annually

Quality and validity

Lineage

The full dataset consists of approximately 160+ VHS tapes (1996 to 2002) and 260+ DVD discs (2003 to present) plus additional back-up tapes. The DVD discs are kept for reference and quality-control purposes at Cefas, Lowestoft, for a period of 5 years, after which they are disposed of. The VHS tapes are now obsolete but will be retained until January 2017 at which time they will be disposed of. Material can be made available upon request (please contact data steward for more information). Positional data and Nephrops burrow counts have been stored in a shellfish access database since 1996. In line with SGNEPS (Study Group Nephrops) recommendations all scientists are trained/re-familiarised using training material and validated using reference footage (measured by Linn’s concordance correlation coefficient (CCC)) prior to recounting each survey footage. A limit of 0.5 is used to identify counters who need further training. On completion of this process, all survey recounts are conducted, as blind counts, by two persons during the survey. Here, the number of Nephrops burrow systems and the activity in and out of the burrows are counted by each minute block (for 7 clear minutes). In cases where the field of view became obscured by cloud, the number of seconds obscured are recorded and all minute blocks with more than 20 seconds obscured are rejected for analysis. After all counts completed again the Linn’s CCC is again applied to check which stations needed to be revisited and were a 3rd or 4th counter needed to be added. Whilst reviewing the videos, the visibility, ground type, trawl marks, occurrence of bio-fauna, ground contact of the sledge, cloud and any other interference is recorded during each one-minute intervals, using a classification key. Example footage and a training presentation are available via the metadata record entitled 'Nephrops underwater TV Surveys - VHS and DVD footage'. For sediment analysis data of these grounds please contact the Cefas sedimentology team. For acoustic data recorded in these grounds (multibeam and backscattered data) please contact Cefas MIST team.

Conformity

Conformity report

specification

title

reference date

date type

publication

effective date

2013-12-10

degree

false

explanation

See the referenced specification

Conformity report

specification

title

reference date

date type

publication

effective date

2010-12-08

degree

true

explanation

See the referenced specification

Data format

name of format

Unknown

version of format

Constraints related to access and use

Constraint set

Limitations on public access

Constraint set

Limitations on public access

Responsible organisations

Responsible party

organisation name

Centre for Environment, Fisheries and Aquaculture Science, Lowestoft Laboratory (CEFAS)

full postal address

Cefas Lowestoft Laboratory

Pakefield Road

Lowestoft

NR33 0HT

UK

email address

data.manager@cefas.co.uk

responsible party role

originator

Responsible party

organisation name

Centre for Environment, Fisheries and Aquaculture Science, Lowestoft Laboratory (CEFAS)

full postal address

Cefas Lowestoft Laboratory

Pakefield Road

Lowestoft

NR33 0HT

UK

email address

data.manager@cefas.co.uk

responsible party role

custodian

Responsible party

organisation name

Centre for Environment, Fisheries and Aquaculture Science, Lowestoft Laboratory (CEFAS)

full postal address

Cefas Lowestoft Laboratory

Pakefield Road

Lowestoft

NR33 0HT

UK

email address

data.manager@cefas.co.uk

responsible party role

distributor

Responsible party

organisation name

Department for Environment, Food and Rural Affairs (DEFRA)

email address

defra.helpline@defra.gov.uk

responsible party role

owner

Responsible party

organisation name

European Commission

email address

info@publications.europa.eu

responsible party role

owner

Metadata on metadata

Metadata point of contact

organisation name

Centre for Environment, Fisheries and Aquaculture Science, Lowestoft Laboratory (CEFAS)

full postal address

Cefas Lowestoft Laboratory

Pakefield Road

Lowestoft

NR33 0HT

UK

email address

data.manager@cefas.co.uk

responsible party role

pointOfContact

Metadata date

2023-01-31T02:06:33

Metadata language