Identification

Title

2015 Cornwall Inshore Fisheries and Conservation Authority (IFCA) Fal Oyster Survey

Abstract

Cornwall Inshore Fisheries and Conservation Authority (IFCA) conduct annual dredge surveys within the Fal Oyster Fishery since taking over management of the fishery in 2014. The aims of the survey were to investigate the relative abundance and distribution of native oysters (Ostrea edulis) within the Fal Fishery management area in the River Fal, Cornwall. In 2015, a total of 79 sites were completed and 769 oysters were recorded. The analysis was done by Geographic Areas; Harbour, Outer Harbour and River.

Resource type

dataset

Resource locator

Unique resource identifier

code

CIFCA_FAL_OYS_2015

codeSpace

Dataset language

eng

Spatial reference system

code identifying the spatial reference system

urn:ogc:def:crs:EPSG::4326

Additional information source

Latham, H. and Trundle, C. 2015. Fal Oyster Survey. Cornwall Inshore Fisheries and Conservation Authority (Cornwall IFCA), Hayle.

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

Keyword set

keyword value

originating controlled vocabulary

title

reference date

date type

creation

effective date

2015-04-07

Geographic location

West bounding longitude

-5.0653

East bounding longitude

-5.0063

North bounding latitude

50.2482

South bounding latitude

50.1554

Extent

Extent group

authority code

title

reference date

date type

creation

effective date

2009-06-18

code identifying the extent

Western Channel and Celtic Sea

Extent group

authority code

title

reference date

date type

creation

effective date

2009-05-01

code identifying the extent

29E4

Extent group

authority code

title

reference date

date type

revision

effective date

2010-01-01

code identifying the extent

water column

Vertical extent information

Minimum value

0.8000

Maximum value

7.0000

Coordinate reference system

authority code

code identifying the coordinate reference system

urn:ogc:def:crs:EPSG::5861

Temporal reference

Temporal extent

Begin position

2015-02-11

End position

2015-02-18

Dataset reference date

date type

publication

effective date

2021-05-12

Frequency of update

asNeeded

Quality and validity

Lineage

The positions of the survey sites were based on previous survey positions from surveys carried out by Cefas/ Cornwall Council prior to Cornwall IFCA taking over management of the fishery in 2014. The survey was carried out onboard research vessel Tiger Lily VI. The oyster dredge used was an Essex-style oyster dredge with a 72 cm blade, rigged with 34 mm diameter steel belly rings and a 45 mm (twin 3 mm nylon twine) mesh back. The dredge was deployed and recovered over the stern of Tiger Lily VI. A target was created in Olex for each site position and a radius ring was added to ensure each tow was 50 m in length. A tow haul method was adopted, similar to that used by the oyster punts. This allowed the dredge tow to be of a known distance and to be easily and consistently replicated. At each survey site the survey vessel was anchored and 60 m of anchor line was let out. The dredge was shot by hand and the slave hauler winch was used to take up 50 m of marked anchor line, resulting in a 50 m dredge tow at a steady 0.5 to 1 knots. The dredge was then hauled aboard by hand and emptied onto a sorting table/ cultch board. Once recovered, the dredge contents were emptied on to the sorting table. If the dredge did not fish, due to being blinded or flipped over, or the sample appeared smaller than it should be for particular areas, the dredge haul was repeated. All positions were recorded using WGS84 projection and all times are recorded as Coordinated Universal Time (UTC). Each sample was photographed on the sorting table alongside a clapper board prior to sorting. Live native oysters were removed and set aside as the sample was sorted. All live oysters were counted and measured across the widest point, to the nearest mm using Vernier callipers. A list bycatch species was made for the whole survey area. The bycatch recording in 2015 was a minor part of the oyster survey and the list of species recorded is shown in the report. Data was entered in situ into a recording sheet set up in Microsoft Excel. The size frequency distribution was graphed in Microsoft Excel and density maps were created in MapInfo Pro Advanced Version 17.0. Analysis was carried out comparing data from the geographic areas; outer harbour, harbour and river. For a full methodology please refer to the report.

Conformity

Conformity report

specification

title

reference date

date type

publication

effective date

2011-02-02

degree

true

explanation

See the referenced specification

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 and permission must be sought if the data will be reproduced in full or part or if used in any analyses.

Constraint set

Limitations on public access

No restrictions to public access

Responsible organisations

Responsible party

organisation name

Cornwall Inshore Fisheries and Conservation Authority

email address

enquiries@cornwall-ifca.gov.uk

responsible party role

originator

Responsible party

organisation name

Cornwall Inshore Fisheries and Conservation Authority

email address

enquiries@cornwall-ifca.gov.uk

responsible party role

custodian

Metadata on metadata

Metadata point of contact

contact position

Data Officer Cornwall IFCA Research Team

organisation name

Cornwall Inshore Fisheries and Conservation Authority

email address

enquiries@cornwall-ifca.gov.uk

responsible party role

pointOfContact

Metadata date

2024-07-22

Metadata language