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Example of results (gross return)

Example of results (gross return). Revenue computation (per month or per year) from catches on studied species + effort proportional ‘a priori’ revenue from other species. Gross return.otherspecies

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Example of results (gross return)

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  1. Example of results (gross return) Revenue computation (per month or per year) from catches on studied species + effort proportional ‘a priori’ revenue from other species Gross return.otherspecies Est nul pour les OTBLN car ils pêchent trop par rapport au revenue de reference (initial gross value) Attention à l ’hypothèse forte d’un revenue constant provenant des others species (calculé à partir de la première année): Qu’est-ce que ça veut dire dans la perspective d’un modele de reallocation de l’effort selon les revenues?? Benthic Intermediate’ trawler metiers BenthicLarge (TTBLN) & HakeNetLarge (GNS) & SpainMainHakeON30-39 (VHVO)

  2. Example of results (selectivity sce.) Abundance trajectories Abundance trajectories ‘Gear Selectivity’ scenario: Better evolution for stocks with increased mesh sizes

  3. Example of results (catch.wt) hake, catch.wt hake: Catches in weight for trawlers are lesser for 110mm than for 70 mm… BenthicLarge nephrops: Catches in weight are greater for 110mm nephrops, catch.wt hake, catch.wt NephropsLarge SpainMainHake …and greater for netters.

  4. Example of results (hake/nephrops) Quantifying technical interactions… Effect on first year hk, discards.wt hk, landings.wt hk, catch.wt % balance - - trawler mesh size neph, landings.wt neph, catch.wt neph, discards.wt + + Hake :Decreasing catches for trawlers (up to -50%) slight increase for netters (~2%). But also…decrease of landings, landings for nephrops remains identical ! …because high decrease of discards for both stocks

  5. Example of results (hake landings.wt) And quantifying the impact on landings in weight (ref: 70 mm versus 110 mm)… % balance of hake landings First year= surplus % balance - + after 5 years deficit Why? Because hake abundance trajectory is better… abundance of older fishes (i.e. bigger) increasing after 5 years. See also the effect on grossreturn and the price evolution?

  6. Example of results (nephrops landings.wt) And quantifying the impact on landings in weight (ref: 70 mm versus 110 mm)… % balance of nephrops landings surplus % balance deficit

  7. Example of results (gross return) Selectivity’ scenario: Impact in terms of revenues Higher for netters price Fish price: Inversion for 110mm sce. due to higher total landing (french market) … But positive gross return balance % balance Trawlers: inversion after 5 years

  8. Example of results (MPA sce.) Abundance trajectories Applying this MPA seems to be beneficial for hake stock…

  9. Example of results (hake abund. - MPA sce.) 23E5 or 20E7 or 19E7 23E5 or 20E7 or 19E7 No MPA 23E5 or 20E7 or 19E7 23E4 or 22E4 or 22E5 MPA • Which are the protected ages? • - age 2 in recru squares • 2-9 ages in repro • & recru squares

  10. Example of results (hake abundance, all ages) No MPA MPA + better recruitment + 12 months, Year5, All Ages, log.scale, topo.colors

  11. Example of results (hake abundance, ages 4-9) No MPA MPA + 12 months, Year5, Ages 4:9, log.scale, topo.colors

  12. Example of results (exploitation) catches.wt landings.wt discards.wt % balance ~+ - + Catches on hake for all fleets decrease near the MPA season but increase other times… …due to a dominant decrease of discards but also a decrease of landings for spanish fleets weight

  13. Example of results (SpainMainHakeON3039) Effort re-allocation in space and time MPA No MPA SpainMainHakeON3039, Effort met 42,Year5, log.scale

  14. Example of results (SpainMainHakeON3039) effort MPA: the reallocation of effort is large but unefficient for this fleet because no available fish in the remaining zone! No MPA - Landing.wt Landing.wt OK Since effort is uniformly distributed on a zone metier, the landings give a direct info on available fish stock to be fished… Morever, q in age-disagregated but not zone-disagregated…

  15. Example of results (BenthicLarge) effort No MPA MPA: minor reallocation (only one square). Increasing landings rather an indirect effect from the decrease for spanish netters… Landing.wt Landing.wt + Since effort is uniformly distributed on a zone metier, the landings give a direct info on available fish stock to be fished…

  16. Example of results (IV) How MPA impact occurs? Due to the preservation of total biomass or, more subtle, to the preservation of critical stages in the life cycle? Effort is reallocated on the inshore zone…but effort on recruitment zone remain constant because of inshore.zone Λ recru.zone MPA noMPA MPA

  17. Example of results (IV) How to choose a priori MPA settings? Protect juvenile => Discards.wt map Protect spawner biomass => hake abundance 4-9 ages map (A posteriori = protect fishermen’ landings?)

  18. An other way to connect ISIS-FISH with FLR…

  19. Isis-Fish & FLR : creating a connection Isis-Fish : freeware in Java for spatial and seasonal simulation of multi-stocks and multi-fleets interactions with complex management rules (ex. MPA, etc…). > http://www.ifremer.fr/isis-fish/ FLR : data structuration in R and set of methods for evaluation of uncertainties in stock assessments and simulation of (multi)stock(s) and (multi)fleet(s) interactions with simple management rules (i.e. HCR). >

  20. Isis-Fish & FLR : creating a connection > using Rserve package (http://stats.math.uni-augsburg.de/Rserve/) R commands can be encapsulated in java methods // in a simulation loop: // each time step, running an xsa on the stock and updating the stock object c.voidEval("my.xsa <- FLXSA(my.stock, indices, FLXSA.control())"); c.voidEval("my.stock@stock.n <- my.xsa@stock.n"); // subsetting SSB var SSB = c.eval("apply(my.stock@stock.n[,myyear,1,myseason,], 1, sum)").asDouble(); // impacting the isis’ management rules if (SSB < referencePoint) { do…} etc.

  21. Northern Hake Base Case using Isis & FLR abundances 1 area 1 fleet with F=qE with E =1 and q=Fwg Stock parameters from TECTAC base Age 0 Age 1 Age 2 FLXSA The match of these results with stock assessment is planned… catches

  22. Northern Hake Base Case using Isis & FLR abundances Why a link… FLXSA output as input for Isis’ management rules: Hake box if SSB <Bpa FLXSA start end catches Alternative case could Be easily implemented Age 0 Age 1 Age 2

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