The objective of the NURSE series of cruises is to collect data to help monitor and understand the functioning of coastal nurseries, as these essential habitats play a decisive role in the recruitment of juveniles of several fish species. Sampling of benthic and demersal populations (invertebrates and commercial and non-commercial fish) has been standardised since the 1980s in order to develop quality indicators for nursery habitats and indicators of the good ecological status of coastal populations.

The series of coastal oceanographic campaigns has been carried out since 1980, between the end of July and the end of September, along the French coast of the Bay of Biscay. The area surveyed by the oceanographic vessel is approximately 220 km². The nursery sectors are visited in turn in order to ensure a follow-up every 3 years. Vilaine Bay, being a special site, has been visited almost every year since 1980. The campaigns follow a stratified random sampling based on bathymetry and sediment cover. Since 2008, this sampling has been systematic, i.e. it is stabilised on a number and distribution of sampling stations that optimise spatial coverage within each nursery. The sampling gear used is a 3-metre beam trawl (type CP3M) designed and operated solely for scientific purposes. The beam and skids are made of metal, weighing 23 kg and 2 x 35.5 kg respectively (total: 94 kg). The net has a 20 mm mesh pocket (stretched mesh), while the back and belly are 40 mm and 30 mm mesh. The standard gear is used without a scraper chain in front of the chained bead (length 4 m, weight 6 kg).

All organisms from the trawl are first identified, counted and then weighed to species. Some samples (stomach contents, muscle, etc.) may be taken according to the specific needs of scientific projects. In this case, the individuals are then frozen on board. The complete protocol for NURSE campaigns can be found in Delaunay D., Brind'Amour A. (2018). Manuel des protocoles de campagne halieutique. Campagnes « Nourriceries ». R.ODE/VIGIES/DCSMM. https://archimer.ifremer.fr/doc/00435/54610/

• Sampling plan(s):

Systemic since 2008, stratified.

• Precision on the type of data:

Changes in the abundance of juvenile fish. Census of the benthic megafauna.

Identifications, counts, weighings

• Parameter(s) observed or measured :

Size, abundance, weight, salinity, temperature, depth

• Resolution of parameter(s) :

Densities of juveniles observed (number/km2), general trend for all species observed.

• Format(s):

The available data exist in the format: csv