Identification

Title

1998 - Ongoing, North Western Inshore Fisheries and Conservation Authority (NWIFCA) Cockle Surveys

Abstract

The NWIFCA conducts cockle surveys across its district in order to inform the management of this fishery. Data is collected on the density of cockles in an area, their status in relation to minimum landing size (20 mm) and age. Samples are also often taken for weighing and production of length frequency tables. This data can be used to estimate other parameters such as the mass of stock on the bed. In the past beds have been surveyed regularly (every year). However, the NWIFCA has moved toward a more adaptive survey strategy where beds are more often surveyed after reports of a possible commercial stock by local area officers.

Resource type

dataset

Resource locator

Unique resource identifier

code

NWIFCA_COC_ALL

codeSpace

http://www.nw-ifca.gov.uk

Dataset language

eng

Spatial reference system

code identifying the spatial reference system

urn:ogc:def:crs:EPSG::4978

Classification of spatial data and services

Topic category

biota

Keywords

Keyword set

keyword value

Keyword set

keyword value

Keyword set

keyword value

originating controlled vocabulary

title

reference date

date type

revision

effective date

2008-01-06

Keyword set

keyword value

originating controlled vocabulary

title

reference date

date type

revision

effective date

2009-11-16

Geographic location

West bounding longitude

-3.7354

East bounding longitude

-2.7356

North bounding latitude

55.0091

South bounding latitude

53.3046

Extent

Extent group

authority code

title

reference date

date type

creation

effective date

2009-06-18

code identifying the extent

Irish Sea

Extent group

authority code

title

reference date

date type

creation

effective date

2009-05-01

code identifying the extent

35E6

Extent group

authority code

title

reference date

date type

creation

effective date

2009-05-01

code identifying the extent

36E6

Extent group

authority code

title

reference date

date type

creation

effective date

2009-05-01

code identifying the extent

37E6

Extent group

authority code

title

reference date

date type

creation

effective date

2009-05-01

code identifying the extent

38E6

Extent group

authority code

title

reference date

date type

creation

effective date

2009-05-01

code identifying the extent

39E6

Extent group

authority code

title

reference date

date type

creation

effective date

2009-05-01

code identifying the extent

37E7

Extent group

authority code

title

reference date

date type

creation

effective date

1954-01-01

code identifying the extent

Irish Sea and St. George's Channel

Extent group

authority code

title

reference date

date type

revision

effective date

2010-01-01

code identifying the extent

benthic boundary layer

Extent group

authority code

title

reference date

date type

revision

effective date

2010-01-01

code identifying the extent

soil and sediment

Extent group

authority code

title

reference date

date type

revision

effective date

2010-01-01

code identifying the extent

troposphere

Extent group

authority code

title

reference date

date type

creation

effective date

2014-05-16

code identifying the extent

VIIa

Temporal reference

Temporal extent

Begin position

1998-01-01

End position

2017-09-21

Dataset reference date

date type

publication

effective date

2013-09-27

Frequency of update

irregular

Quality and validity

Lineage

Beds are surveyed using a series of survey points in a grid pattern, loaded onto GPS. This grid has a size of 50 to 500 m dependent on the size of bed and requirement for resolution. However, 250 m is the most common size. At each survey point a quadrat is placed onto the bed and cockles within this quadrat recorded. Two sizes of quadrat are used depending on the number and size of cockles present. A 0.5 m quadrat is used for less dense areas of large cockles. A jumbo is first used to bring cockles to the surface. A 0.1 m box quadrat is used for areas with dense spat settlements. Here the sediment within the quadrat is passed through a sieve. The number of cockles within a quadrat is recorded along with their age (determined from growth rings) and size (oversize, undersize, spat). Oversize (or size) cockles are those that do not pass through an opening 20 mm square. When there is a large number of spat an estimate is made as to their total number. Samples of cockles found in quadrats are taken for analysis in the lab. These are measured using a digital calliper to the nearest .5 mm and a wet weight taken. Available outputs from these surveys vary. These include raw data, amalgamated data, GIS data, thematic maps and reports.

Conformity

Data format

name of format

version of format

Constraints related to access and use

Constraint set

Use constraints

Data is freely available for research or commercial use providing that the originators are acknowledged in any publications produced. A charge may be applied to cover costs of compiling and sending data.

Constraint set

Limitations on public access

No restrictions to public access

Responsible organisations

Responsible party

contact position

North Western IFCA

organisation name

Northwestern Inshore Fisheries and Conservation Authority

email address

dassh.enquiries@mba.ac.uk

responsible party role

originator

Responsible party

contact position

North Western IFCA

organisation name

Northwestern Inshore Fisheries and Conservation Authority

email address

dassh.enquiries@mba.ac.uk

responsible party role

custodian

Metadata on metadata

Metadata point of contact

organisation name

Northwestern Inshore Fisheries and Conservation Authority

email address

science@nw-ifca.gov.uk

responsible party role

pointOfContact

Metadata date

2017-09-21

Metadata language