Well, I don’t necessarily disagree with what Mr. Dunn is trying to convey, but his response on pre-season forecasting misses some key points that need clarification. First, when he says there has been little improvement in the accuracy or precision of pre-season forecasts of run strength he should know that pre-season forecasting is just one part of a very complex management structure of Fraser River Sockeye which includes advisory processes, in-season management (environmental monitoring, test fisheries, catch monitoring, hydroacoustic monitoring at Mission and Qualark), and post-season activities (stock assessment, run-size adjustments, etc.). The pre-season forecast is an initial plan that is needed by fisheries so it is expected that it will be adjusted in-season as a clearer picture of what is returning develops. If you just had the in-season component then it makes it more difficult for fisheries (recreational, First Nation and commercial) to plan for resources and manpower or for managers to plan for what regulations may be needed before the inseason kicks in or harvest and escapement targets.
Pre-season forecasts are not really forecasts of run strength – they are forecasts of run size, the timing of the runs and the diversion rate of returning Sockeye. Run size is further refined in-season by the Pacific Salmon Commission by the use of test fisheries and hydroacoustic counts at Mission and Qualark. Similar to pre-season forecasting, in-season run size estimates also use complex models. Improvements to the precision and accuracy of forecasts are still work in progress and those that are responsible are doing there best to address these concerns to make forecasts better…..but I mean let’s face it….there is very large variability in survival rate of juveniles from year to year. For Fraser Sockeye, there are only 2 places where smolt outmigration is enumerated (Chilko and Cultus). If you look into it more you will find out that it’s not that simple, but the forecasts that are develop here are very good considering the huge variability. For 2014, it was very difficult to forecast given a large amount of data points in one area and then 2010 all off on its own. It’s for topics like this that you need a real expert to talk about this. Randall Peterman is basically the guru of this subject so I will attach the following pdf which really explains what Mr. Dunn couldn’t.
http://www.sfu.ca/cstudies/science/resources/adaptingtochange/Peterman2008-Pre-seasonForecasting.pdfJust because Fraser Sockeye returns have been good lately doesn’t mean that we that don’t keep trying to investigate things like marine survival. Data gaps were clearly noted in the Cohen Final Report. Although it is directed at addressing the survival of steelhead, Coho and Chinook, the Salish Sea Marine Survival Project is one of those projects that can possibly assist Fraser Sockeye forecasters.
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Topic: To Be Expected (Read 4139 times)