Biotic data collected during identification trawls on the PELGAS integrated survey in the Bay of Biscay
|Temporal extent||2000-05 -2018-05|
|Author(s)||Doray Mathieu1, Pennors Laurence1, Grellier Patrick1, Raguenes Pierre1, Lespagnol Patrick1, Duhamel Erwan1|
|Affiliation(s)||1 : Ifremer, France|
|Keyword(s)||integrated survey, midwater trawl, pelagic, Bay of Biscay|
The Pélagiques Gascogne (PELGAS, Doray et al., 2000) integrated survey aims at assessing the biomass of small pelagic fish and monitoring and studying the dynamics and diversity of the Bay of Biscay pelagic ecosystem in springtime. PELGAS has been conducted within the EU Common Fisheries Policy Data Collection Framework and Ifremer’s Fisheries Information System. Details on survey protocols and data processing methodologies can be found in Doray et al., (2014, 2018).
This dataset comprises the abundance (no. of individuals), biomass (metric tons), mean length (cm), mean weight (g) of marine organisms collected by midwater trawling to identify fish echoes detected during PELGAS surveys (2000-2018). All parameters have been raised to the trawl haul level. Trawl haul metadata and species reference list are also provided.
|Utilisation||Those data have been collected by midwater trawling to identify fish echoes detected during acoustic-trawl surveys. Trawl hauls have not been conducted according to a random sampling design. Biotic data provided here have to be combined with fisheries acoustic data to safely assess the biomass or abundance of marine organisms in survey area. Biomass and abundance indices provided in this dataset are not representative of the biomass or abundance of marine organisms in the Bay of Biscay and should be used for presence/absence study only.|
|Acknowledgements||PELGAS surveys have been funded by the European Common Fishery Policy Data Collection Framework, the Marine Strategy Framework Directive, and Ifremer. We want to acknowledge the joint efforts of R/V Thalassa crews and PELGAS scientists that made the survey possible. The authors particularly thank Jacques Massé, Pierre Beillois and Ludovic Bouché.|
Identification hauls have been carried out using the R/V Thalassa II 2 doors, headline: 76 m foot rope: 70 m (or 57 m x 52 m at depths below 50 m) pelagic trawls (cf. Brabant and Nedelec, 1988 for detailed plans). Since 2007, a consort survey has been routinely organized together with French pairs trawlers which accompanied R/V Thalassa for approximatively 20 days, to conduct supplementary identification hauls (Massé et al., 2016). Trawl hauls have been typically conducted in straight line for about 30 minutes at 3 knots.
See PELGAStotalSamplesReadme.csv file for fields description.