Nitrogen and carbon stable isotope data for Queen scallop Aequipecten opercularis (Linnaeus, 1758) (AphiaID: 140687) muscle tissue. These data were originally collected for the study of isotopic baselines in food webs and for the development of isoscapes for northern European shelf seas. Data collection is described in greater detail in the following publications: Barnes, C., Jennings, S. & Barry, J.T. (2009) Environmental correlates of large-scale spatial variation in the δ13C of marine animals. Estuarine, Coastal and Shelf Science, 81, 368-374. Jennings, S. & Warr, K.J. (2003) Environmental correlates of large-scale spatial variation in the δ15N of marine animals. Marine Biology, 142, 1131-1140. Jennings, S. & Van der Molen, J. (2015) Trophic levels of marine consumers from nitrogen stable isotope analysis: estimation and uncertainty. ICES Journal of Marine Science, 72, 2289-2300. Description and structure of data file: Data file name: "SIA_N_C_Aequipecten_opercularis_NEAtl_27092016_v1.csv" Data set description: 535 records of δ13C and δ15N natural abundance measurements in adductor muscle tissue from individual Aequipecten opercularis collected from the Celtic Sea, Channel, Irish Sea and North Sea in the northeast Atlantic. Data were collected in 2001 and 2010. Data structure: A .csv file comprising 536 rows by 9 columns, including one row of headers (variable names). Missing values for "Size" are denoted "-999". Variable name Variable definition Units Range(numeric values) Latitude Decimal latitude degrees 49.39 - 60.248 Longitude Decimal longitude degrees -7.39 - 6.806 Year Year year 2001 - 2010 DOY Day of year day 197 - 332 Size Shell height mm 16 - 81 (missing values -999) Cperc Carbon content % by dry mass 29.66 - 65.91 Nperc Nitrogen content % by dry mass 7.46 - 18.56 d13C δ13C ‰ -20.37 - -15.59 d15N δ15N ‰ 3.86 - 12.55 Authentication after download: The dataset comprises 536 rows by 9 columns, including one row of headers (variable names). The sums of the 535 records in each of columns one and two, "Latitude" and "Longitude", will be 28279.96 and -896.999 respectively if all rows are downloaded. Methods of data collection and processing: In 2001, scallops were caught with a Grande Ouverture Verticale (GOV) demersal trawl and 2-m or 4-m beam trawls (Jennings et al., 1999, ICES, 2012). The 2-m beam trawl and GOV trawl were fished from R.V. "Cirolana" and the 4-m beam trawl from R.V. "Corystes". Stations in the North Sea, Irish Sea and Channel were fished using the standard protocol for fisheries surveys (ICES, 2012). The GOV and 4-m beam trawls were fitted with a cod-end of 20 mm stretched mesh and the 2-m beam trawl was fitted with a cod-end of 4 mm stretched mesh. The GOV and 4-m beam trawls were towed for 30 min at a speed of approximately 4 knots, while the 2-m beam trawl was towed for 5 min at 1 knot. Several scallops were retained at each site, with a preference for individuals with a shell height of 50–60 mm when these sizes were available. Individual shell heights were measured to the nearest mm and each scallop was immediately frozen to -30 degrees celsius. On return to the laboratory, the scallops were thawed and a 1–2 g sample of adductor muscle tissue was removed. This tissue was refrozen, freeze dried and ground to a fine homogenous powder with a pestle and mortar (particles <60 um). All equipment was cleaned after processing each sample and the powdered material transferred to a new glass vial.Each sample of ground tissue was thoroughly mixed and a 1.0 mg sample weighed into a tin capsule for stable isotope analysis. The carbon and nitrogen stable isotope composition of the powdered tissue samples was determined using continuous flow isotope ratio mass spectrometry (CF-IRMS) at the University of Newcastle and PDZ Europa using a Europa Scientific 20-20 IRMS and linked preparation module. Two samples of reference material (a standard mix of ammonium sulphate and beet sugar) were analysed after every five tissue samples to calibrate the system and compensate for drift with time. Stable isotope composition was expressed in conventional delta notation, relative to the level of 13C in Pee Dee Belemnite and 15N in atmospheric nitrogen. Approximately 20% of scallop tissue samples were processed in duplicate for quality control. Experimental precision (based on the standard deviation of replicates of the internal standards) was <0.15 for C and N. In 2010, scallops were caught with 4 and 8 m beam trawls and Grande Ouverture Verticale trawls during bottom trawl surveys of the North Sea, Channel, Irish Sea, and Celtic Sea (ICES, 2012). Surveys were conducted by R.V. "Corystes", R.V. "Endeavour" and R.V. "Tridens". Several scallops were retained at each site, with a preference for individuals with a shell height of 50–60 mm when these sizes were available. Individual shell heights were measured to the nearest mm and each scallop was immediately frozen to -30 degrees celsius. Laboraotory processing followed the procedure described in 2001 except that the powdered material was transferred to a glass vial for transportation before weighing into tin capsules. The carbon and nitrogen stable isotope composition of the powdered tissue samples was determined using a Europa Scientific 20-20 IRMS with a Europa Scientific Roboprep-CN preparation module by Iso-Analytical Ltd. Two samples of reference material (a standard mix of ammonium sulphate and beet sugar) were analysed after every four to six tissue samples to calibrate the system and compensate for drift with time. Experimental precision was <0.20 for C and N. Carbon stable isotope analysis was conducted without lipid extraction. Previous work has shown that δ13C data can be corrected for differences lipid content using C:N ratio data (Fry et al. 2003) and that the results are consistent with those obtained following chemical lipid extraction (Sweeting et al. 2006). The δ13C data included in the published data set are not corrected for differences in lipid content, but the percentage C and N data provided can be used to make the correction if required. Logan et al. (2008) provide further information on methods of lipid correction and their performance. All documentation, tracking of samples and entry of data was independently reviewed by at least one other scientist and all projects supporting the collection and processing of samples followed the Joint Code of Practice for Research (JCoPR) of the U.K. Department of Environment, Food and Rural Affairs and the U.K. Research Councils. Independent review involved line by line checking of the reference code used to track the sample from capture through processing and isotope analysis against (1) the capture location and log from the cruise, (2) the record of labelling and processing and (3) the record that included the results of the stable isotope data. Reference materials used during the analysis of 2001 and 2010 samples were calibrated against, and traceable to, inter laboratory comparison standards distributed by the International Atomic Energy Agency(IAEA). Methodological references: Fry, B., Baltz, D.M., Benfield, M.C., Fleeger, J.W., Gace, A., Haas, H.L. & Quiñones-Rivera, Z.J. (2003) Stable isotope indicators of movement and residency for brown shrimp (Farfantepenaeus aztecus) in coastal Louisiana marshscapes. Estuaries, 26, 82–97. ICES. 2012. Manual for the International Bottom Trawl Surveys. Series of ICES Survey Protocols. SiSP 1-IBTS VIII, 68 pp. ICES, Copenhagen. Jennings, S., Lancaster, J.E., Woolmer, A. & Cotter, A.J. (1999) Distribution, diversity and abundance of epibenthic fauna in the North Sea. Journal of the Marine Biological Association of the United Kingdom, 79, 385-399. Logan, J. M., Jardine, T. D., Miller, T. J., Bunn, S. E., Cunjak, R. A. & Lutcavage, M. E. (2008) Lipid corrections in carbon and nitrogen stable isotope analyses: comparison of chemical extraction and modelling methods. Journal of Animal Ecology, 77, 838–846. Sweeting, C.J., Polunin, N.V.C. & Jennings, S. (2004) Tissue and fixative dependent shifts of δ13C and δ15N in preserved ecological material. Rapid Communications in Mass Spectrometry, 18, 2587-2592. Sweeting C.J., Polunin N.V.C. & Jennings S. (2006) Effects of chemical lipid extraction and arithmetic lipid correction on stable isotope ratios of fish tissues. Rapid Communications in Mass Spectrometry, 20, 595-601. Principal funding sources: U.K. Department of Environment, Food and Rural Affairs. Grants: MF0731 “Development and testing of ecological indicators and models to monitor and predict the ecosystem effects of fishing” (2002-2007), MF1001 “Ecosystem approach to fisheries” (2007-2012) and MF1225 “Developing the evidence base to support the integration of fisheries and environmental management” (2012-2017). Acknowledgements: I am very grateful to Karema Warr, Richard Ayers, Trevor Boon, Grant Course, Tracy Maxwell, Chris Firmin, Mary Brown, Jim Ellis, Ingeborg de Boois and the officers and crew of R.V. "Corystes", "Cirolina", "Endeavour" and "Tridens" for their efforts at sea, to Peter Davison, Roger Hillier and Jon Santillo for processing samples, to Anne Bruce, Rowan White, University of Newcastle, PDZ Europa and Iso-Analytical for conducting the stable isotope analyses and to Carolyn Barnes and Stephanie Cogan for organising and checking data. Prepared by: Simon Jennings, Centre for Environment, Fisheries and Aquaculture Science, Lowestoft, Suffolk, NR33 0HT, United Kingdom Contact email: simon.jennings@cefas.co.uk