Identification

Title

2015 - Present, 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 purpose of the survey was initially to assess the distribution and abundance of native oysters (Ostrea edulis) within the Fal Fishery management area in the River Fal, Cornwall. Since 2016 the survey has been developed to also assess queenies (queen scallop, Aequipecten opercularis; variegated scallop, Mimachlamys varia) distribution and abundance. Slipper limpets (Crepidula fornicata) were initially recorded at each site using a SACFOR style scheme which was amended in 2018 to a count for this species. The aims of the survey were to investigate the relative abundance and distribution of native oysters (O. edulis), scallops (queen scallop, A. opercularis; variegated scallop, M. varia) and slipper limpets (C. fornicata) within the Fal Oyster Fishery. The distribution of substrate types across the fishery and species of bycatch were also recorded at each site in 2019.

Resource type

dataset

Resource locator

Unique resource identifier

code

CIFCA_FAL_OYS_2015-Present

codeSpace

Dataset language

eng

Spatial reference system

code identifying the spatial reference system

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

Additional information source

All reports are available on request

Classification of spatial data and services

Topic category

biota

Keywords

Keyword set

keyword value

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

water column

Vertical extent information

Minimum value

0.8000

Maximum value

10.0000

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

2021-11-24

Dataset reference date

date type

publication

effective date

2021-05-12

Frequency of update

annually

Quality and validity

Lineage

In 2014 Cornwall Inshore Fisheries and Conservation Authority (IFCA) took over the management of the Fal oyster fishery, following the expiry of the Truro Port Fishery Order 1936 (as amended), and assumed responsibility for the continuation of oyster surveys and monitoring the stock of native oysters (Ostrea edulis) within the fishery, previously conducted by CEFAS/Cornwall Council. For data continuity the 95 sample sites used previously by CEFAS/ Cornwall Council were largely adopted for this survey, the exceptions being sites located on sensitive habitats (including seagrass and maerl beds) which could be damaged by the survey. A 72cm blade, Essex-style oyster dredge is used, rigged with 34mm diameter steel belly rings and a 45 mm (twin 3 mm nylon twine) mesh back. At each survey site the survey vessel is anchored and 60m of anchor line let out, the dredge is shot by hand and the hydraulic winch used to take up 50m of anchor line, resulting in a 50m dredge tow at a steady 0.5 to 1 knots. Each sample is photographed on the cultch board alongside the clapper board prior to sorting. Live oysters and scallops (queen/ variegated scallop) are counted and measured across the widest point (oysters) and along the length of the valve (from the hinge to the outer edge) (Scallops), to the nearest millimetre. Observations of substrate and by-catch are recorded alongside the oyster and scallop data for each dredge sample. An abundance scale is used to categorise substrate content, including slipper limpet (Crepidula fornicata) shell abundance. This should not be considered a definitive record of by-catch present at each site as it is not the primary reason for the survey. 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 and management areas; A, B and C to ensure compatibility of the data with the oyster permit returns. For a full methodology please refer to the survey reports for each year.

Conformity

Conformity report

specification

title

MEDIN data guideline for fish and benthos data by trawl or dredge

reference date

date type

publication

effective date

2018-10-08

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

2021-11-24

Metadata language

eng