virtual availability

[k-doering-NOAA]

Imported from redmine, Issue #61493 Opened by @RickMethot on 2019-03-18 Status when imported: New

create concept of explicit availability, as distinct from availability as a component of selectivity.

Also create an option such that 1-availability be an option ffor 2 area models such that fish that are available in fleets in one virtual area are the complement of fish available in the other area

Plan development in conjunction with IATTC and SWFSC

[k-doering-NOAA]

comment from @RickMethot on 2019-03-18: Another way to do this would be to reproduce what was in the old age-area based SS from the early 1990s. One option in that SS version allowed areas to be as they are in SS today with movement. The other, which was used for hake, was to allow the stock to be treated as totally mixed at the beginning of each time step and then be partitioned in an age-specific way between areas before fishing started in each area. The goal for that approach was the US-Canada hake split.

So the concept of age-specific areal-availability would be created by age-specific partitioning of the stock among areas.