cbaf7fb65c17845220a9bef0cc460a21 English dataset Carly Cassidy University Marine Biological Station (UMBS), Millport Millport KA28 0EG carlycassidy@hotmail.co.uk pointOfContact 2019-11-04 MEDIN Discovery metadata standard 2.3.8 4326 2006 UMBSM Clyde Sea Conservation Status of the native oyster (Ostrea edulis L.) in Scotland 2006-01-01 publication UMBSM18175 A PhD was conducted at the University marine Biological Station Millport (UMBSM) and presented tot the University of London. The study investigated the native European flat oyster, Ostrea edulis, which was identified under UK government initiatives to conserve biodiversity as a "priority species". Research aimed to determine the conservation status of O. edulis in Scottish waters. A review management measures was undertaken and the development of guidelines for the conservation of O. edulis in Scotland were established. Philip Smith University Marine Biological Station (UMBS), Millport Millport KA28 0EG philip.smith@millport.gla.ac.uk originator Kathryn Stevenson University Marine Biological Station (UMBS), Millport Millport KA28 0EG kathryn.stevenson@millport.gla.ac.uk custodian notPlanned Documents Marine Environmental Data and Information Network Species distribution GEMET - INSPIRE themes, version 1.0 2008-01-06 revision Fish and shellfish catch statistics Shellfish abundance and biomass in water bodies SeaDataNet P021 parameter discovery vocabulary 2009-11-16 revision Restrictions apply. Please contact UMBSM for further details. otherRestrictions DASSH terms and conditions apply (https://www.dassh.ac.uk/terms-and-conditions) English biota Charting Progress 2 Sea Areas 2009-06-18 creation Irish Sea -5.7349 -4.9658 54.9208 56.1333 2004-02-09 2005-12-01 Data Archive for Seabed Species and Habitats (DASSH) Data Manager 01752 633102 01752 633291 Marine Biological Association of the UK, The Laboratory, Citadel Hill Plymouth PL1 2PB dassh.enquiries@mba.ac.uk distributor dataset Three study sites were established for investigation on the west coast of Scotland. West Loch Tarbert (Argyll), Linne Mhuirich, (Loch Sween) (Argyll) and Loch Ailort (Highlands) were selected due to the high population densities of O. edulis within their waters. Additional sites on the west and north coast of Scotland were visited in order to collect basic demographic data (Loch Ryan and Mull and Ulva). Survey sites around Mull and Ulva have not been included within this study due to commercial confidentiality however details are available to appropriate users upon request from the author. Population estimates of selected wild O. edulis populations were surveyed in 2004, using the multi-level transect survey methodology (section 3.2.2.1;Krebs, 1999). Fifteen sites within 10 geographical locations were surveyed. Transects were randomly located throughout oyster populations, except where transects were placed in areas of highest density. The locations, Ordinance Survey grid reference, dates and the number of transected completed at each study site is provided within the report. Each survey area was divided into 50m length sections along the shore. Each section was sub-divided into a grid with rectangular cells of 50 x 5m. One grid cell per section was randomly selected for surveying purposes. Cells were located using a GPS receiver and surveyed in random order. A 30m tape measure placed parallel to the shore marked out a transect within selected cells. A 1m squared quadrat was used to sample both sides of the transect at three randomly chosen distances within a 10m sub-section. A surveyed area of 18m squared was established per transect. Direct counts of living oysters, predators (Asterias rubens and carcius maenas) and competitor species (Anomia ephippium and Mytilus edulis) were recorded. Dial callipers were used to measure shell height and length. Percentage cover by different substrata was determined, including the percentage cover of algae. The mean density and abundance of oysters were estimated. Belt-transect surveys were also utilised. Each survey area was divided into 20m length sections along the shore and each section was sub-divided into a grid containing rectangular cells of 20 x 2m. Randomly selected cells were located by measuring alongshore and offshore coordinates with a tape measure. Transects marked with a 20m tape measure, parallel to the shoreline, were established within selected cells. Sampling was achieved by 1m square quadrats which were placed contiguously on either side of the transect giving a total survey area of 40m squared. Oysters within the quadrats were counted and shell height and length was measured. Limiting factors (settling substrata) for the abundance of O. edulis populations in Scotland were investigated. Oyster habitats at Taynish (Linne Mhuirich), Dun Mhuirich (Linne Mhuirich), Rhu (West Loch Tarbert) and Eilean nan Trom (Loch Ailort) were divided into 25m alongshore sections. Eight sections were randomly chosen and surveyed. A 25m tape measure was laid parallel to the shore along the midline of the bed section. Ten 1m squared quadrats divided into 5cm squares were placed randomly on bothsides of the tape measure. percentage cover of substrata was estimated. The numbers of O. edulis and A. ephippium were counted and the substrata they were attached to was recorded. The percentage cover and associated substratum of sessile organisms (algal species, tubeworms (Pomatoceros spp), barnacles (Chthamalus montagui, Semibalanus balanoides), mussels (Mytilus edulis) and tunicates (Ciona intestinalis, Ascidiella aspersa) was also recorded. Red "Marley" ridge tiles (45 x 30 x 8cm) were used as spat collectors which were laid in two parallel lines spaced 5m apart. The lower line was approximately 1m from the lower edge of the coarse-sediment substrata.. Forty six tiles were laid with 23 on each line. Tiles were placed at 20m intervals. Tiles were placed singly or as a pair (randomly decided). Spat collectors were laid in June 2004 and removed in February 2005 and relaid in June 2005 and removed in December 2005. The recruitment success of O. edulis was investigated. Allee effects were investigated for limiting potential. Inter-individual distances of oysters within six 36m squared plots at Taynish and Dun Mhuirich were investigated. Spatial distribution between exploited and unexpolited areas, and the distance from the centre of the bed to the edge was assessed. Plots were spaced 20m apart. The first plot was located at the approximate alongshore centre of the bed area. A buffer zone of 1m width around plot boundaries were established. Plots were sub-divided into 1m squared quadrats. The quadrats were further sub-divided into 10 x 10cm squares. Each square was surveyed. Oysters were numbered and their position was recorded on a reference map. Distances between the central point of each oyster and its three closest neighbours were measured using a tape measure. Shell length and height was measures using dial callipers to 0.1mm.