Unlike pre-terminal fisheries, terminal fisheries target only stocks in a
Particular river. The most common strategy for in-river management is fixed
Escapement. An escapement goal is established for one or more stocks and
Catches are adjusted to meet the escapement goal
The .riv file specified on line 31 of the .opt file details the exact
Mеthod of applying in-river harvest strategiеs and details of this method. There
Are three different management types that can be used for fixed escapement: a
Weak stock strategy, a combined stock strategy and a fixed harvest rate strategy
Examples of each of these file types are shown in Files of type riv
Files of type riv
All natural stocks incorporate a truncated Ricker Spawner/Recruit
R equals S times the natural exponential of the quantity Alpha times the quantity 1 minus S over Beta
Where
S = the number of adult spawners on the spawning grounds
R = the number of adults recruiting to the fishery
Alpha = the productivity parameter
And Beta = the capacity parameter
For each stock, age, and fishery, Base Period Harvest Rates are the
Estimated average rate for the years 1979 through 1982. All other Harvest Rates in the
Model are scaled up or down from these base period rates by using Harvest Rate
(HR) Scalars
The HR Scalars can be used to examine a general set of questions regarding
How are harvest rates on particular stocks affected by harvest rate
Changes in terminal fisheries?
How would specific harvest rate strategies affect rebuilding?
How do shaping options differently impact particular stocks?
Such questions can be evaluated through the use of .fp files (the “fp”
Suffix stands for “Fishery Policy”)
Catch equals run times 1 minus the natural exponential of minus Q times E
Where Q is called the “Poisson Catchability Coefficient” and E is the amount of
Fishing effort
“Incidental Mortality” refers to fish that die as a result of the fishing process
But are not part of the legal catch or harvest. These mortalities include shakers
(i.e., chinook that are hooked and brought up to the boat but are released
Both legal and sub-legal chinook that are hooked and
Brought up to the boat during coho fisheries at times when all chinook are not
Legal to land and sell). Shakers and CNRs have increased natural mortality rates
Due to the handling process
Production impacts include a broad range of watershed activities
A few
Examples are hatcheries and spawning channels that enhance reproductive
Success, dams that increase mortality of both upstream adult migrants and
Downstream smolt migrants, fish ladders that help improve upstream survival
Bypass systems that help reduce downstream mortalities at dams, and logging
Practices that reduce available spawning habitat
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