DOI: 10.14466/cefasdatahub.149
title: Modelled and observed fish feeding traits for the North Atlantic and Arctic Oceans (1836-2020) and population estimates of fish with different feeding traits from Northeast Atlantic scientific trawl surveys (1997-2020)

description: The data we provide here have been assembled to categorise fish into feeding guilds and determine change in populations of fish with different feeding traits relevant to food web status assessment advocated by OSPAR. We provide four datasets: the first is a csv file titled ‘stomach data observations’ contains observations from fish stomach contents of individual prey weight, prey functional group (i.e., zooplankton, benthos, fish, nekton and other), predator taxonomy, predator size, and the region and year the samples were collected (Table 1; see Column_headers_readme.txt); the second is a csv file titled ‘modelled stomach data’ provides predictions from a linear mixed effects model of individual prey weight based on those stomach contents observations, alongside modelled estimates of prey counts and biomass which enable the full collation of stomach contents information to be used in our feeding guild classification (Table 2; feeding guilds are predatory categories assigned using cluster analysis on stomach content data; see Thompson et al., 2023); the third dataset is a shapefile titled ‘feeding guild responses in survey data’ and provides haul-level estimates of feeding guild species richness, numbers of fish and their biomass based on scientific trawl surveys from the Northeast Atlantic (Tables 3-4); the fourth is a shapefile titled ‘temporal changes in feeding guilds’ which contains correlation coefficients and p values following Kendall’s τ trend analysis between mean haul-level values of feeding guild biomass and species richness for each assessment strata and year. Kendall’s τ scores of –1 to +1 represent a 100% probability of a decreasing or increasing trend, respectively (Table 5).
Stomach contents data

We draw together stomach contents data primarily collected from the North Atlantic shelf seas, with important contributions from the Baltic, Barents and Norwegian Seas in the Arctic Ocean. These data were sourced from a combination of previously published and unpublished data including DAPSTOM (Pinnegar, 2019), ICES Year of the Stomach (Daan, 1981; ICES, 1997), the Northeast US continental shelf (Smith & Link, 2010), Northern Spanish shelf (Arroyo et al., 2017), Gulf of Cadiz (Torres et al., 2013), Swedish-, Icelandic-, Norwegian-, French- (Cachera et al., 2017; Timmerman et al., 2020; Travers-Trolet, 2017; Verin, 2018) and German-led surveys (e.g., FishNet, https://www.nationalpark-wattenmeer.de/wissensbeitrag/fishnet/; BioConsult, 2023). The observations used to model prey weight contain information from 621,040 fish stomachs (Table 1), from 146 predator taxa collected between 1963 – 2020 and includes larvae (<1 g) to adults (up to 351 kg). The full dataset contains predictions of prey weights and counts based on predator size, predator taxa and prey functional group information from 944,129 fish stomachs (Table 2), 227 predator taxa collected between 1836 – 2020 and includes larvae (<1 g) to adults (up to 351 kg).

Scientific trawl survey data

Scientific trawl data were obtained from Lynam and Ribeiro (2022), a data product derived from Northeast Atlantic groundfish data from surveys undertaken between 1983-2020 with observations for the biomass and numbers of species size classes standardised to the area swept for each haul. We make use of data collected using otter trawls between 1997 – 2020. We process the data by categorising fish into feeding guilds using taxonomic and size information and sum estimates of biomass, numbers, and species richness by feeding guild for each haul observation. We provide the unique assessment units used in the pilot assessment to determine change in feeding guild responses (Lynam et al., 2022; Lynam & Piet, 2022; Thompson et al., 2023). We provide details of the columns used in Table 3, a summary of the specific surveys used in Table 4. Details of the columns in the data containing correlations and p values based following Kendall’s τ trend analysis are provided in Table 5.

Associated scientific study

These data were processed for the study "Fish functional groups of the North Atlantic and Arctic Oceans ", by Murray S.A. Thompson, Izaskun Preciado, Federico Maioli, Valerio Bartolino, Andrea Belgrano, Michele Casini, Pierre Cresson, Elena Eriksen, Gema Hernandez-Milian, Ingibjörg G. Jónsdóttir, Stefan Neuenfeldt, John K. Pinnegar, Stefán Ragnarsson, Sabine Schückel, Ulrike Schückel, Brian E. Smith, María Ángeles Torres, Thomas J. Webb, and Christopher P. Lynam (in prep; see also Thompson et al., 2023).