Publication on data.gouv.fr
Species and habitats - Sprattus sprattus - All ages - Recurrence - IBTS Q3 (1991-2010)
Species habitat occupation, observed during the third quarter IBTS from 1991 to 2010, has been expressed as rare, occasional, frequent, recurrent depending on density levels and variability over time.
The survey extends in the North Sea, which corresponds to ICES divisions IVb and IVc. The study area is divided into rectangles of 0.5d latitude and 1d longitude using a systematic sampling strategy. The sampling gear is a high opening bottom trawl well adapted for catching demersal species, with a 10 mm mesh size (side knot) for catching juveniles. This sampling gear is polyvalent and is well adapted to the varying seabed types encountered in the study area.Two 30 minutes hauls are performed within each rectangle of the ICES grid. The fishing hauls are chosen using professional fishing plans or found by prospecting. The fishing method is standardised: sampling stations have been each year at similar locations and identical sampling gear is used. At each sampling station, all the fish species are sorted, weighed, counted and measured. For certain commercial species, bony structures (otoliths) are collected.
Purpose: not specified