The Channel is an area heavily influenced by fishing, mainly for neighbouring countries but also more widely for northern European countries. The ecological and economic impact of the exploitation of fisheries resources needs to be estimated so that fishing activity remains sustainable while taking into account the limitation of resources and its effect on the environment. To meet this need, EU Member States must carry out at-sea surveys to estimate the abundance and distribution of fish stocks, independently of commercial fishing data. To achieve this objective, the Channel Ground Fish Survey (CGFS) is part of the European Fisheries Monitoring Programme, which collects data on exploited stocks (maturity, age/size structure, recruitment index). The time series started in 1988 and is used annually by the European stock assessment working groups to determine the exploitation status of the main commercial fish species. Initially focused on the eastern Channel, the CGFS now aims to cover the whole Channel to provide fishery-independent data for this area as well. The 2018 CGFS survey will start in Brest in mid-September to collect fishery-independent data to assess the living marine resources of the Channel using a large vertical opening trawl (LOT). For 30 days, 117 30-minute hauls will be made in daylight at a speed of 4 knots. Carried out on the R/V Thalassa, the CGFS will provide the opportunity to sample and better understand the whole ecosystem, which will meet both the requirements of the MSFD and the need for an ecosystem approach to fisheries on a European scale. Thus, the physico-chemical properties of the water, the phytoplankton and zooplankton communities, the abundance of fish eggs, the species composition will be measured and analysed throughout the CGFS study. After the survey, the collected data will be validated and provided to national and European databases (SIH, Harmonie, Coriolis, DATRAS), which will allow the working groups and the general public to have access to these data.

October 1988: Start of the first CGFS campaign on the N/O Gwen Drez. Duration of the hauls 15 minutes, data processing with the "marzine" software, no separation of the sexes on the selachians, no separation of the loligo (squid)

October 1990: Duration of the hauls 30 minutes, processing of selachians by sex

October 1993 : Loligo treatment by species

October 1995: Addition of trawl points in bays to characterise nurseries. Integration of the CGFS programme into the international IBTS group

October 1997: Change of management software (OSACA)

October 2004: Suppression of additional trawling in bays.

October 2008: Monitoring of benthos

October 2014: Inter-calibration with the N/O Thalassa

October 2015: CGFS campaign carried out on the N/O Thalassa - adjustment of stations according to draught - change from 110 to 74 stations in the Eastern Channel

September 2018: Start of the West Channel Series

September / October 2020: No authorisations for work in English waters

Number of observation or measurement points: 122

6 strata in the Western Channel - 48 hauls in the Western Channel and 74 in the Eastern Channel

• Sampling design(s):

Random, stratified

• Precision on the type of data :

- Merlangius merlangus, Pleuronectes platessa, Dicentrarchus labrax, Gadus morhua, Mullus surmuletus, Selachians

- Benthic invertebrates, fish

- Inventory of different types of waste (plastic, glass, metal, plastic bottles, leather and fabrics, fishing gear, miscellaneous)

- Data Pelagic biotope

- Primary production

- Zooplankton

- Ichtyoplankton

- Small pelagic fish

- All fish and invertebrates

- Top predators

- Macro-waste

• Parameter(s) observed or measured :

For fauna :

- Collection of otoliths and scales, sexes, sexual stages, individual weights

- Determination, counting, measuring (fish)

- Resolution of parameter(s) :

- By size class (lower cm)

- Lower Cm, ½ cm lower

For waste :

- Density

Other parameters:

- Temperature, salinity, fluorescence.

- Taxonomy and abundance of phyto and micro zooplankton.

- Abundance and distribution of marine mammals

- Abundance and distribution of marine birds.

- bathymetric acquisitions with multibeam echosounders

- Resolution of parameter(s) :

- For fauna: By fishing operation, continuous survey (CUFES), systematic analysis of scientific fishing catches

- For litter: Density per hectare, By sampling operation on the course

• Format(s):

The available data exist in the format: csv