(courtesy of Randall Peterman)
Vismon can only load input files with a special format. Below are two sample data files ready to be opened with Vismon.
[contains only the average values across the 500 Monte Carlo trials]
[contains all outputs of Monte Carlo trials]
We applied Vismon to a specific fisheries management problem in Alaska, U.S.A. In the
late 1990s and early 2000s, several chum salmon populations in the Arctic-Yukon-Kuskokwim (AYK)
region of western Alaska suffered large and rapid decreases in abundance, which led to greatly
reduced commercial and subsistence catches [AYK]. A computer simulation model for chum salmon
was therefore developed to evaluate alternative management policies that might help these
salmon populations recover and also avoid future occurrences of low salmon abundance [CPZ09].
That simulation model's output was used as input to Vismon.
Management objectives of salmon managers in the AYK region have three components:
(1) allow sufficient subsistence catches for people who rely on them for their livelihood,
(2) allow enough catch by commercial fishing boats to maintain their economic viability, and
(3) maintain abundances of spawners (those that "escape" the fishing gear, i.e.,
"escapement") near a biologically determined target number.
Because managers differ in which particular metrics they use to reflect how close they are
to reaching these objectives, the simulation model produced 12 indicators (performance measures)
for each management action, including the mean and median values (which managers prefer to
maximize) and two types of indicators that should be minimized: year-to-year variability
over time in salmon escapement, subsistence catch, and commercial catch, and the chance over
time of extremely low escapements and catches occurring.
Fisheries scientists [CPZ09] ran the stochastic AYK chum simulation model for 100 years for
each of 121 combinations of management actions (11 different escapement targets and 11
different harvest rates). This process was repeated for 500 Monte Carlo trials. Output
from these model runs were then used as input to Vismon.
[AYK] AYK sustainable salmon initiative background and goals. http://www.aykssi.org/background-goals.
[CPZ09] Collie J. S., Peterman R. M., Zuelke B.: A Risk Assessment Framework for AYK Salmon. Tech. rep., Project completion report for the Alaska Sustainable Salmon Fund, Nov. 2009.