Macco - Fleet analysis

Objective

Definition of metiers, fleets and strategies for ISIS-Fish model for the bay of Biscay demersal fishery using DCF-6 metiers as a baseline.

Data

• Noirmoutier is used as the limit between the North and the South of the bay of Biscay. Noirmoutier is considered to be in the North of the bay of Biscay.
  
• Analysis of the metier is performed on vessels superior to 12m only.
• The gear of reference (gear_isis) used for a fishing sequence is the gear provided by the sacrois algorithm.
• Key species are SOL, HKE, NEP, MEG, MNZ, WHG, RJC, RJN, CET. Landings of species which are not considered as key species are summed in a group of other species (OTH).
• The metier of reference for each fishing sequence is the metier DCF_6 associated to the gear of reference (gear_isis_metier_dcf6).
• Metiers with a number of fishing sequence equal to 1000 over the time period considered in the study are all merged in one metier called “metier_low_activity”.
• Metiers which only capture species that are not key species are merged in one metier called “metier_OTH” for each gear isis.

Space and time

Data processing starts in 2010 and ends in 2018 for ices zones 27.8.a, 27.8.b, 27.8.d.

Number of fishing sequence for each year in the final dataset.

Fleets

Number of vessels per years and fleets isis

Gears

Proportion of cumulative revenue of landings per gear with key species only

Proportion of cumulative landings in kg per gear with key species only

Landings proportion per gear isis

Landings proportion per gear isis with key species only

Metiers

From 2010 to 2018, the number of DCF-6 metier is 153 in the sacrois data. When we only consider metiers that catch key species, the number of DCF-6 metier is 138.

Metier isis

Number of fishing sequences per super metier over the whole time period.

Proportion of engin per metier isis over the whole time period.

Mean landings in (kg) per super metier over the whole time period.

Proportion of species in landings per super metier.

Proportion of species in landings per super metier without OTH species.

Metier isis zone

Hypothesis :

• Vessels below 15m are constraints by their size and metier zone is computed for northern and southern vessels separately.
• Vessels above 15m have no constraints and metier zone is shared for northern and southern vessels.
• When the total number of cells exceeds 50 and the average annual fishing time is above 250 hours two zone are considered. A zone of low intensity of the fishing effort and one zone of high intensity of the fishing effort.

D_[15-Inf[ m

D_other[12-15[ m

#> NULL

F_[15-Inf[ m