/harvest/norris/mig.pdf The report describes migration algorithms for five models=97-State Space Model, PSC Chinook Model, PSC Selective Fishery Model, Proportional Migration Model, and fram=97-in a common matrix notation. A key finding in the report was a matrix notation for the PM model, which does not have a migration algorithm per se. Based on this notation, the report concludes that: "=85 the PM model makes the tacit assumption that for a given cohort and time step, fish migrate from all donor regions at the same rate." Jim suggested that we should do some testing to see if there are violations of this assumption. Rich Comstock noted that the assumption may not be correct, because the transition matrix in the PM model is not directly analogous to the migration matrices of the other models. Jim agreed to delete the statement from the report and requested suggestions for an intuitive description of the PM matrix terms. 5. Report on Alaska Transboundary Salmon Model (Norma Jean Sands). Norma Jean Sands briefly described a fisheries bioeconomic model she has been developing to examine allocation issues in Pacific salmon between the US and Canada. The model currently incorporates four stocks (sockeye and pink salmon from each country) and twelve fisheries from the northern boundary area between Alaska and British Columbia. The migration of stocks is through the waters of the other country first and then the country where spawned, and is through outer fisheries, then inner fisheries, and finally terminal fisheries. Terminal fisheries do not intercept fish that spawn in the other country. The migration parameters (percentage of each stock that migrates through the waters of each fishery) were determined by an iterative process to best give the average catches, interceptions, escapements, and harvest rates observed in the early 1990s. This gives a linear flow of fish through the system, but not all fish within a stock follow the same path and stocks are not equally vulnerable to the various fisheries. The model objective is to test various allocation schemes and compare how they do on stock productivity and fisheries economics. The model solves for a sustainable stable solution and does not incorporate annual variability in stock production or prices. The three allocation schemes tested and their modeled consequences were: 1. Balancing interceptions resulted in fisheries only being conducted in terminal fisheries (i.e., interceptions =3D 0) and in stock production being underutilized by the fisheries. 2. Maximizing sustainable yield of all stocks simultaneously resulted in high stock production and economic gain, although the share of the economic gains between the two countries was not proportional to stock production by each countries streams. 3. Maintaining a fixed harvest rate by each fishery that approximates the harvest rates experienced in the early 1990s resulted in relatively high stock productivity and fisheries benefits for both countries. Jim Scott asked how the observed harvest rates were estimated. Norma replied that they were based on run reconstruction of the stocks prepared by the Northern Boundary Technical Committee. 6. FRAM Status Report (Jim Scott). One of the provisions of the agreement between the Tribes and WDFW regarding selective fisheries was to modify FRAM so it can analyze selective fisheries. Jim Scott reported that Jim Packer at WDFW was taking the lead on this issue. His approach is to double the number of stocks to allow for marked and unmarked components. The exploitation rates will be scaled differently on marked and unmarked fish in selective fisheries. There will be a meeting at WDFW on July 15 to discuss FRAM modifications in more detail. Jim also mentioned that NMFS and the PFMC are sponsoring a salmon model workshop in Santa Rosa, CA on October 8-9. 7. Code Design Report (Troy Frever). Troy briefly described some relevant code elements of the adult upstream migration model he is working on with Rich Zabel. The river is divided into "reaches" separated by "locations." The model currency is a cohort of fish. Each cohort has a matrix of abundances by time step (rows are locations; columns are time steps). Each element of the matrix is the number of fish exiting that location at that time step. Thus, the sum of the columns is not 1. The computation engine loops over time steps, locations, then cohorts. Some of the code elements that may be used in the new model are: = chornographer; = geographer; = cohort manager. 7. State Space Model Report (Ken Newman). Ken distributed a report summarizing his updates to the State Space Model. A copy of the report is available at: /harvest/newman/statespace.pdf He is using the same Humptulips data as in the past, but has changed from a Gamma Distribution to a Beta Distribution for modeling migration. For each year and stock, the model estimates six parameters: 2 for the Beta Distribution describing initial abundance; 2 for the catch equations (one each for Canada and US fisheries); and 2 for the Beta Distribution describing movement. The latest results showed quite a bit of difference in the two fishing mortality parameters. In 1985 the Canadian parameter was much larger than the US parameter, but in 1986 the US parameter was larger. It was hoped that these parameters would show more consistency because they are similar to catchability coefficients. 8. General Migration Modeling Report (Robert Kope). Robert noted that most of the models, except PM, are all single pool models that usually ignore spatial effects. Also, the PSC Selective Fisheries Model is the same model that has been used to model tuna migration. Robert introduced the "Box Car" model used to model Fraser River sockeye. This model assume a constant migration rate and dispersion, but has no diffusion as the migration goes on. Thus, the migration matrix for this type of stock has a series of 1s on the sub-diagonal, and 0s elsewhere. At each time setp, all the fish in one area move into the next region. When fishing occurs in a region, a large gap in the distribution occurs that persists throughout the rest of the migration. Ken Newman questioned how the Fraser River managers estimated the constant migration rate. No specific answer, other than it comes from the technical management group every year. [Robert: Is this right? Maybe you can fill in some details here.] 10. Model Comparison Report (Jim Scott). A work group met on April 22 in Olympia to discuss methods for comparing alternative migration algorithms. Jim Scott handed out a summary of this meeting. The general approach is to create a synthetic Monte Carlo dataset with minimal complexity to facilitate evaluation of alternative algorithms. The dataset will be designed with the intent of developing an understanding of the effects of the following factors on model performance: = varying levels of interannual variability in the migration of a stock; = variability between stocks in the underlying migration patterns; = variability in the temporal pattern and magnitude of fisheries; = varying levels of uncertainty in the estimated number of CWT recoveries; = level of geographic and temporal resolution. Measures of model performance will include the MAPE and MPE for catch, escapement, and exploitation by stock. It is anticipated that the relative performance of alternative algorithms may depend upon the factors identified above. Jim noted that he needs the State Space Model algorithm in order to do this work. Ken agreed to provide it. Jim Norris suggeted using an individual based model (IBM) to generate the synthetic data set. There was some discussion about the problem of what algorith to use to generate the Monte Carlo synthetic data. Peter noted that if we use Ken=92s State Space Model (SSM) in the IBM to generate synthetic data, the SSM will perform the best in the tests. There was no clear resolution of this problem. Jim Anderson commented that a model with both physical and biological elements would be a good model. The meeting adjourned at 4:00 p.m. Next meeting is scheduled for August 22 at NMFS Montlake lab, at 9:00 a.m.