1f4e0812e8484979c82649bfff912e60 English 26dee2f510202899e51ae2e5c876a51c dataset Cornwall Inshore Fisheries and Conservation Authority Data Officer Cornwall IFCA Research Team enquiries@cornwall-ifca.gov.uk pointOfContact 2024-07-22 MEDIN Discovery metadata standard 2.3.8 urn:ogc:def:crs:EPSG::4326 2024 Cornwall Inshore Fisheries and Conservation Authority (IFCA) Fal Oyster Survey 2024-04-12 publication CIFCA_FAL_OYS_2024 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. In 2018, an addition to the survey was made to record the number of individual slipper limpets (Crepidula fornicata) at each site. 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 were also recorded at each site and species of bycatch were recorded across the survey area as a list of species present. In 2024, a total of 81 sites were completed and a total of 2,861 oysters, 2,963 scallops and 3,384 slipper limpets were recorded. The analysis was done by Management Areas; A, B and C. Research Team Cornwall IFCA Cornwall Inshore Fisheries and Conservation Authority enquiries@cornwall-ifca.gov.uk originator Research Team Cornwall IFCA Cornwall Inshore Fisheries and Conservation Authority enquiries@cornwall-ifca.gov.uk custodian asNeeded Marine Environmental Data and Information Network NDGO0005 Species distribution GEMET - INSPIRE themes, version 1.0 2008-01-06 revision Shellfish abundance and biomass in water bodies SeaDataNet P021 parameter discovery vocabulary 2009-11-16 revision 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. otherRestrictions No restrictions to public access 250 English biota Charting Progress 2 Sea Areas 2009-06-18 creation Western Channel and Celtic Sea International Hydrographic Bureau, Limits of Oceans and Seas 1954-01-01 creation English Channel SeaDataNet vertical extent keywords 2010-01-01 revision water column -5.0653 -5.0063 50.1554 50.2482 2024-01-18 2024-01-01 2.6000 13.0000 Jenkin, A., Sturgeon, S., Trundle C., Daniels, C. and Street, K. 2024. Fal Oyster Survey 2023 Summary Report. Cornwall Inshore Fisheries and Conservation Authority (Cornwall IFCA, Hayle). Research Team Cornwall IFCA Cornwall Inshore Fisheries and Conservation Authority enquiries@cornwall-ifca.gov.uk distributor dataset MEDIN data guideline for species and benthos data by trawl or dredge 2023-05-11 publication See the referenced specification true 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 using the A frame on 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 towing warp was run via the A frame mounted hydraulic winch. The towing warp was marked off so that the length (m) of cable deployed at any time was known; this was generally fixed for an average depth and altered only if a depth change was sufficient to cause the dredge to fish too heavily or lightly. The dredge was recovered using the hydraulic winch and/ or A frame. 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. A target was created in HYPACK MAX to indicate the start of line (SOL) and end of line (EOL). 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, queen scallops and slipper limpets were removed and set aside as the sample was sorted. All live oysters and queen scallops were counted and measured across the widest point, to the nearest mm using Vernier callipers. The weight (g) was recorded for oysters where possible to the nearest 0.1g. All slipper limpets were counted, as individuals and as part of a chain. Observations of the catch composition (substrate) were recorded for each dredge sample. A clapper board was filled out per site for the volume of the dredge as a percentage (25%, 50%, 75% and 100%) of how full the dredge was when it was at the surface and the percentage composition for the following categories; mud, shell (live and dead), weed, gravel, vegetation (sticks and leaves), dead maerl and stone in increments of 5% so that the catch composition per dredge equalled 100%. The values for all measurements recorded were relayed verbally via video conferencing to a member of staff working from home who was recording the data into a Microsoft Excel spreadsheet. The size frequency distribution was graphed in Microsoft Excel and size class distribution plots were created in MapInfo Pro Advanced Version 17.0. Analysis was carried out comparing data from the management areas; A, B and C. For a full methodology please refer to the report.