11ca8d363bb6b348f57b569b4c24910f English dataset Carly Cassidy University Marine Biological Station (UMBS), Millport Millport KA28 0EG carlycassidy@hotmail.co.uk pointOfContact 2019-11-11 MEDIN Discovery metadata standard 2.3.8 urn:ogc:def:crs:EPSG::0 urn:ogc:def:crs:EPSG::4326 1997-1999 University Marine Biological Station Millport (UMBSM) Clyde Sea Nephrops Trawling Discards Survey 1997-1999 University Marine Biological Station Millport (UMBSM) Study Contract Clyde Sea Nephrops Trawling Discards Survey EC Study Contract 96/092 1999-11-01 publication MEDIN-114 The principle project objective investigated the discards associated with the process of trawling for Nephrops norvegicus in EC waters. The present study assessed the discard composition and proportion of the total catch from Nephrops trawls in the Clyde Sea area (Scotland) and in the Central Adriatic. The fate of floating, sinking and settled (on the sea bed) discards was investigated. In the Central Adriatic study site, the focus of the study was to investigate the importance of discards to the diet of Nephrops and the food web in general. The study compares trawl samples taken from North and South Clyde Sea area sites due to the differences in hydrographic, geographic, sedimentological and biological factors. P.G. Moore University Marine Biological Station (UMBS), Millport Millport KA28 0EG dassh.enquiries@mba.ac.uk originator Kathryn Stevenson University Marine Biological Station (UMBS), Millport Millport KA28 0EG kathryn.stevenson@millport.gla.ac.uk custodian notPlanned Delimited Documents Marine Environmental Data and Information Network Species distribution GEMET - INSPIRE themes, version 1.0 2008-01-06 revision Shellfish abundance and biomass in water bodies Zoobenthos taxonomic abundance Fishing by-catch SeaDataNet P021 parameter discovery vocabulary 2009-11-16 revision The contents of the study may not be reproduced unless the source of the material is indicated. 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 -5.6744 -4.8560 55.1757 56.0506 1997-08-01 1999-08-01 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 This study has been carried out by researchers at the University Marine Biological Station Millport (UMBSM), Istituto di Ricerche sulla Pesca Marittima and the Fisheries Research Services, Marine Laboratory Aberdeen (MLA) and with the financial assistance of the European Commission. The report does not necessarily reflect the views of the European Commission. The study project is in support of the Common Fisheries Policy. Sample sites within the Clyde Sea area were situated in both Northern and Southern areas. This allowed comparisons between Nephrops populations and differences in two sub-areas of the Clyde Sea to be established. The Clyde Sea are was divided into Northern and Southern regions by an imaginary line devised between Troon and the tip of Holy Island. Sites in the Clyde Sea area used for SCUBA investigations of the benthic processing of discards were established in Loch Sween (ca 15m) and Loch Riddon (ca 20m). Transect lines and mapping grids were already established at the Loch Sween study site due to a previous UMBSM study conducted at the same location (EC Project No. 94/069). An area in the Fairlie Channel (North Clyde Sea) and an area in the South Clyde Sea were investigated using UWTV experiments. Both sites were used in creel experiments. Time Lapse Camera (TLC) investigations were conducted off Keppel Pier (Isle of Cumbrae). UWTV (Kongsberg Simrad OE1358) was deployed in North and South Clyde Sea sites to investigate the fate of submerged and benthic discards. Baited longlines were also used to establish the scavengers of discards. The discard composition and the proportion of Nephrops catches in the North Clyde Sea was monitored monthly onboard commercial prawn trawlers or RV Aora (UMBSM). Those of the South Clyde Sea were obtained quarterly. The composition of discard sub-samples were taxonomically analysed and size-frequency distributions were investigated. Damage assessments of Nephrops discards (commercially undersized) were performed for individuals of a carapace length of less than 25mm. The fate of Nephrops discards and bycatch was investigated by using baited (whole discarded Nephrops or 'heads') traps and creels which were deployed for 48 hours in both Clyde Sea areas. In the South Clyde Sea area, traps baited with both Nephrops and bycatch were deployed. In each experiment, 2 creel fleets (with 27 creels each in total) were used in each site. Each fleet was then divided into three blocks containing 9 creels each and they also contained three replicate creels. CCTV observations were used to analyse the fate of discards at the surface. The fate of submerged and benthic discards were observed by SCUBA divers and UWTV surveys respectively. Direct observations (SCUBA) assessed the sinking rates of discards. In the South Sea area, a longline baited at 2m depth intervals was deployed for 24 hours to assess mid water scavengers of discards. The bottom of the longline was deployed at a depth of 66m. A baited time-lapse camera (TLC) was established at Keppel Pier to record discard utilization times and the influence of different scavenger species. Night recordings were established with the help of an infra-red camera. Discards were scattered in the camera field of view (at the camera frame base) by SCUBA divers. Footage was recorded for 48 hours. A second TLC experiment was carried out for 28 hours. Baited UWTV camera experiments were carried out in both Clyde Sea areas. The UWTV camera was deployed from the RV Aora (UMBSM). The UWTV unit was composed of a Kongsberg Simrad OE1358 camera fitted with three lamps (Osprey/Bowtech) and infra-red filters (Farnell 177-143) and was mounted on a heavy frame. Bait was tied in rows across the camera frame base. UWTV deployments were performed for 1 to 4 hours in duration. Quadrat surveys involving SCUBA divers were also performed to assess the fate of discards and the interactions between scavengers. The number of scavengers observed within quadrats which surrounded bait were counted. Baited transect lines were incorporated. Two hours after the bait was deployed, feeding and approaching scavengers were observed by divers. Predator assessments were conducted by divers.