Reference Points

Author

Fulton, Beth (Environment, Hobart)

Published

May 22, 2023

Reference points for fisheries include four options in Atlantis:

  1. For target species
  2. For forage species (or species of secondary importance)
  3. For byproduct species
  4. For bycatch species

A broken stick pattern of management is assumed for all these options. This means target reference points (refA, refB for quantitative assessments and their matching refC, refD which is the buffered versions assuming an old assessment) as well as the limit reference point. You also need to set whichref to indicate which set of reference points apply to each species:

For example

Reference points and trend lengths for use in dynamic TAC setting

targ_refA 0.48 Target reference point - tier1 or tier8 (the US and Norwegian version of Australia’s tier1)

targ_refB 0.40 Target reference point - tier1 or tier8 (the US and Norwegian version of Australia’s tier1)

targ_refC 0.60 Target reference point - tier2

targ_refD 0.50 Target reference point - tier2

lim_ref 0.20 Limit reference point (used by all tiers)

forage_refA 0.40 Forage target reference point - tier1

forage_refB 0.40 Forage target reference point - tier1

forage_refC 0.50 Forage target reference point - tier2

forage_refD 0.50 Forage target reference point - tier2

forage_lim_ref 0.20 Forage limit reference point

byproduct_refA 0.20 Byproduct target reference point - tier1

byproduct_refB 0.20 Byproduct target reference point - tier1

byproduct_refC 0.25 Byproduct target reference point - tier2

byproduct_refD 0.25 Byproduct target reference point - tier2

byproduct_lim_ref 0.20 Byproduct limit reference point

bycatch_refA 0.20 Bycatch target reference point - tier1

bycatch_refB 0.20 Bycatch target reference point - tier1

bycatch_refC 0.25 Bycatch target reference point - tier2

bycatch_refD 0.25 Bycatch target reference point - tier2

bycatch_lim_ref 0.20 Bycatch limit reference point

Flag to incidcate which set of reference points to use.

Enter 0 = forage (“secondary”) reference points, 1 = targ_ref reference points,

2 = “byproduct” reference points and 3 = bycatch reference points - one per fished species

whichref 47

2 0 3 3 0 2 1 3 1 3 3 3 2 1 0 1 0 1 1 1 1 1 2 2 2 0 2 3 2 3 3 3 3 3 3 1 3 3 3 3 3 3 3 0 3 3 3 3 3 3 3

Additional parameters required along with the reference point information when using them in fisheries management in Atlantis are

Virgin biomasses for use with pseudo assessment (typically dynamically calculated in model instead)

estBo 47

512 824 1273 103612 328 281896 8020 22817 9753 811182 403340 2978 68611 51114 200654 584.246566 11011 1823 3817 4623 13919 476245 290432 184953 106812 561 17675 88 44926 643 19358 54744 4244 675 1028 458760 0 64833 500249 0 103891 1500158 0 390124 2930675 241888146 417926 0 21352 5417350 95029940

Fishing rate (F) that equates with BrefA (i.e.F to apply if B > Bref)

Fref 47

0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Fishing rate (mFC scalar) to apply if reopening a fishery

Fref 47

0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2

F to apply at high biomass levels if using tier8

Fref_High 47

0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2

An extension has been added to let this happen at the guild level instead of the species level - as explained here .

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