MEDITS catch data: Bentho-demersal assemblages of the Gulf of Lion and eastern Corsica (North-western Mediterranean) from 2016 to present

The MEDiterranean International Trawl Survey (MEDITS) started in 1994 within the cooperation between several research Institutes from four Mediterranean Member States (France, Greece, Italy, Spain) of the European Union. Along the time, till to the advent of the European framework for the collection and management of fisheries data, new partners from Slovenia, Croatia, Albania, Montenegro, Malta and Cyprus joined the MEDITS project. On the French Mediterranean shelves specifically, MEDITS covers the Gulf of Lion and Eastern Corsica. The MEDITS project aims to have fishery resource abundance estimators that are comparable between different Mediterranean zones, based on the same standardized observation methods. These should allow the reproduction, under similar conditions, of abundance indices for the different species over time. Standardized observation protocols relating in particular to the location of sampling stations, the characteristics and methods of use of the fishing gear, biological observations, computer file formats, have thus been defined jointly between the various partner countries and are applied by all teams participating in the MEDITS programme. Thus five depth strata have been defined for all sectors: 10-50 m, 50-100 m, 100-200 m, 200-500 m and 500-800 m. The basic principle is that of a distribution of the stations in proportion to the surface of the strata, with random selection of the stations in each stratum. Biological observations are carried out according to the protocol described in the latest version of "Instruction manual MEDITS" (MEDITS handbook version 9, 2017). Here, the data produced during the French MEDITS over the Gulf of Lion (GSA 7) and the eastern coast of Corsica (GSA 8) is made available.

Disciplines

Fisheries and aquaculture, Biological oceanography, Environment

Keywords

MEDITS, Gulf of Lion, Eastern-Corsica, North-western Mediterranean, demersal fish, benthic invertebrates, exploited species, marine macro-litter, gelatinous zooplankton

Location

43.62161N, 41.353564S, 9.828861E, 2.797611W

Devices

On an internationally established methodological basis, haul duration ranges from half-hour (on 10 to 200 m depth) to one hour (on 200 m to 800 m depths), using a standard scientific trawl used since 1994 on all European bottom trawl surveys (Spedicato et al., 2019). It was implemented in accordance with the recommendations described in the MEDITS handbook (MEDITS handbook version 9, 2017), being hauled at 3.5kt and using a reduced mesh size (20mm stretched) in the cod-end allowing for the capture of juveniles. All the species collected, including, since 2012, all the megabenthic invertebrates, are sorted, weighed and counted (Lesbats, 2022). For 84 species, measurements are also carried out and on 41 of these species (32 selachians, 5 bony fish, 4 crustaceans, 2 cephalopods) all the individual parameters are collected (weight, sex, maturity, size, otoliths for the two mullets and hake and illicii for both monkfishes). In the recent period, marine litter and large gelatinous zooplankton (such as jellyfish) by-catches are also recorded since 2013 and 2015 respectively. The systematic collection of basic indicators on environmental conditions at the bottom is also carried out (temperature since 1998 and salinity since 2016).

The data is in the ELevated FIsh Catch (ELFIC) format, where all sub-sampled observations were elevated to the level of the total catch in the catch table. It is also strongly recommended to standardise catch values per km² or per hour as haul duration, gear geometry and swept area may vary from one observation to the next, especially depending on depth.

The present dataset is composed of a pdf document describing the structure and content of each file, and 5 csv files containing the metadata and data.

Data

FileSizeFormatProcessingAccess
The present dataset is composed of a pdf document describing the structure and content of each file, and 5 csv files containing the metadata and data.
2 MozipQuality controlled data
How to cite
Certain Gregoire, Jadaud Angelique, Vaz Sandrine, Metral Luisa, Cheret Isabelle, Billet Norbert, Schull Quentin, Tessier Emmanuel, Cornou Anne Sophie, Souplet Arnauld (2024). MEDITS catch data: Bentho-demersal assemblages of the Gulf of Lion and eastern Corsica (North-western Mediterranean) from 2016 to present. SEANOE. https://doi.org/10.17882/99052

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