This readme file was generated on 2024-05-21 by Serena Donadi and provides a list and description of each file included in the dataset. ----------------------------------------- DATASET GENERAL INFORMATION ----------------------------------------- Title of dataset: Clupeids and stickleback biomass, fishery landings, and hydrographic variables from the Baltic Sea Creator(s)/Primary investigator(s): Serena Donadi, ORCID 0000-0002-8920-9630 Persistent identifier of dataset: https://doi.org/10.5878/ka8r-8e34 Related publication for description of project, methods etc: Serena Donadi, Agnes Olin, Michele Casini, Johan Eklöf, Mårten Erlandsson, Ronny Fredriksson, Olavi Kaljuste, Niklas Larson, Jonas Nilsson, Ulf Bergström. "Reduced predation and competition from herring may have contributed to the increase of three-spined stickleback in the Baltic Sea", ICES Journal of Marine Science, submitted. ----------------------------------------- FILE OVERVIEW ----------------------------------------- "herring_biomass.csv" Brief description of content: Biomass of herring of two size classes, estimated per year (2001-2020) and ICES rectangles in the Baltic Sea. "sprat_biomass.csv" Brief description of content: Biomass and abundance of sprat, estimated per year (2001-2020) and ICES rectangles in the Baltic Sea. "stickleback_biomass.csv" Brief description of content: Biomass of stickelback, estimated per year (2001-2020) and ICES rectangles in the Baltic Sea. The data on fish biomasses were collected by the Baltic International Acoustic Survey (BIAS), which is performed yearly in September–October under the coordination of the International Council for the Exploration of the Sea (ICES). Hydroacoustic fish counts are coupled with information on species and size distributions from trawl hauls to estimate abundance and biomass of pelagic fish across the Baltic Sea. Biomass estimates of stickleback, herring and sprat per year for each ICES statistical rectangle (ca. 55 × 55 km size, corresponding to 0.5 degrees in latitude × 1 degree in longitude) was available from 2001 in the Central Baltic and from 2007 in the Bothnian Sea. Fish biomass calculations for the Bothnian Sea in 2007–2019 and for the Central Baltic in 2014–2019 were made using the StoX software (version 2.7) and the disaggregated BIAS data available in the ICES database for acoustic and trawl surveys (https://www.ices.dk/data/data-portals/Pages/acoustic.aspx), according to the method developed by the Working Group on Baltic International Fish Survey (WGBIFS) (ICES Scientific Reports 2021, 3:02). The few rectangles that had acoustic data but lacked trawl samples were not included. Due to a lack of disaggregated BIAS data for the Central Baltic in 2001–2013, sprat and herring biomass estimates were extracted from the ICES WGBIFS access-database for aggregated BIAS data (ICES Scientific Reports 2021, 3:02), while stickleback biomass estimates were obtained from the BIAS data including only Swedish areas. Total biomass of stickleback, herring and sprat per year and ICES rectangle were divided by the water area of the respective rectangle at 10 m depth to obtain yearly estimates of biomass per square nautical mile (nmi²). "ICES_Hydrographic_data.csv" Brief description of content: Temperature, salinity and nutrient content, estimated per year (2001-2020) and ICES rectangles in the Baltic Sea. Data were extracted from Copernicus Marine Service Information. The nutrient concentration data were produced using the biogeochemical model ERGOM one-way online-coupled with the ice-ocean model system NEMO (doi.org/10.48670/moi-00012). The salinity and temperature data were produced by DMI (Danmarks Meteorologiske Institut) using NEMO (doi.org/10.48670/moi-00013). All variables were averaged over two depth intervals, 0–20 m and 0–100 m depth. If the sea bottom was shallower than 20 m or 100 m depth, respectively, the average value of the whole water column was used. Data of temperature and salinity are expressed as averages for summer (April–September) and winter (October–March). Concentrations of nitrate, ammonium and phosphate (nmol/m3) were estimated for the period October–March. "landings_herring.csv" Brief description of content: Commercial landings of herring, expressed as tons per year (2003-2019) and ICES rectangles in the Baltic Sea. "landings_sprat.csv" Brief description of content: Commercial landings of sprat, expressed as tons per year (2003-2019) and ICES rectangles in the Baltic Sea. Data on commercial landings were provided by the Scientific, Technical and Economic Committee for Fisheries (STECF, https://stecf.jrc.ec.europa.eu/dd/effort/graphs-quarter) for the years 2003–2015, and by the Joint Research Centre (JRC, https://jeodpp.jrc.ec.europa.eu/ftp/jrc-opendata/FAD/fdi2020/) for the years 2016–2019. Relationship between files: The datasets can be merged using the field "year" and "ICES". ----------------------------------------- DATA-SPECIFIC INFORMATION FOR "herring_biomass.csv" ----------------------------------------- License: Creative Commons Public Domain Dedication CC0 Number of columns/variables: 5 Number of rows/cases: 2056 Codes for missing or empty data: missing data = NA Variable list: Year: year ICES: ICES statistical rectangle (ca. 55 × 55 km size, corresponding to 0.5 degrees in latitude × 1 degree in longitude) region: Baltic Sea basins, abbreviations: Bothnian = Bothnian Sea, Central_Baltic = Central Baltic. HERR_below18_B_nm2: Biomass of small herring (total length < 18 cm), unit: tons per squared nautical mile. HERR_above18_B_nm2: Biomass of large herring (total length > 18 cm), unit: tons per squared nautical mile. ----------------------------------------- DATA-SPECIFIC INFORMATION FOR "sprat_biomass.csv" ----------------------------------------- License: Creative Commons Public Domain Dedication CC0 Number of columns/variables: 3 Number of rows/cases: 2042 Codes for missing or empty data: missing data = NA Variable list: Year: year ICES: ICES statistical rectangle (ca. 55 × 55 km size, corresponding to 0.5 degrees in latitude × 1 degree in longitude) SPRAT_B_nm2_tot: Biomass of sprat, unit: tons per squared nautical mile. ----------------------------------------- DATA-SPECIFIC INFORMATION FOR "stickleback_biomass.csv" ----------------------------------------- License: Creative Commons Public Domain Dedication CC0 Number of columns/variables: 4 Number of rows/cases: 1028 Codes for missing or empty data: missing data = NA Variable list: ICES: ICES statistical rectangle (ca. 55 × 55 km size, corresponding to 0.5 degrees in latitude × 1 degree in longitude) SD: ICES subdivision Year: year STSP_B_nm2_tot: Biomass of stickleback, unit: tons per squared nautical mile. ----------------------------------------- DATA-SPECIFIC INFORMATION FOR "ICES_Hydrographic_data.csv" ----------------------------------------- License: Creative Commons Public Domain Dedication CC0 Number of columns/variables: 16 Number of rows/cases: 4465 Codes for missing or empty data: missing data = NA Variable list: ICES: ICES statistical rectangle (ca. 55 × 55 km size, corresponding to 0.5 degrees in latitude × 1 degree in longitude) Year: year po4_20: average phosphate concentration for 0-20 m depth interval nh4_20: average ammonium concentration for 0-20 m depth interval no3_20: average nitrate concentration for 0-20 m depth interval no3_100: average nitrate concentration for 0-100 m depth interval nh4_100: average ammonium concentration for 0-100 m depth interval po4_100: average phosphate concentration for 0-100 m depth interval T_okt_mar_100: average winter temperature for 0-100 m depth interval T_okt_mar_20: average winter temperature for 0-20 m depth interval T_apr_sep_100: average summer temperature for 0-100 m depth interval T_apr_sep_20: average summer temperature for 0-20 m depth interval Sal_okt_mar_100: average winter salinity for 0-100 m depth interval Sal_okt_mar_20: average wintersalinity for 0-20 m depth interval Sal_apr_sep_100: average summer salinity for 0-100 m depth interval Sal_apr_sep_20: average summer salinity for 0-20 m depth interval ----------------------------------------- DATA-SPECIFIC INFORMATION FOR "landings_herring.csv" ----------------------------------------- License: Creative Commons Public Domain Dedication CC0 Number of columns/variables: 3 Number of rows/cases: 2867 Codes for missing or empty data: missing data = NA Variable list: ICES: ICES statistical rectangle (ca. 55 × 55 km size, corresponding to 0.5 degrees in latitude × 1 degree in longitude) Year: year Landings_herr: Commercial landings of herring expressed as tons per year ----------------------------------------- DATA-SPECIFIC INFORMATION FOR "landings_sprat.csv" ----------------------------------------- License: Creative Commons Public Domain Dedication CC0 Number of columns/variables: 3 Number of rows/cases: 2108 Codes for missing or empty data: missing data = NA Variable list: ICES: ICES statistical rectangle (ca. 55 × 55 km size, corresponding to 0.5 degrees in latitude × 1 degree in longitude) Year: year Landings_sprat: Commercial landings of sprat expressed as tons per year