Fraser River Sockeye Fisheries and Fisheries Management - Cohen ...

FISHERIES HARVESTINGOverview of FisheriesFraser sockeye are harvested at numerous points along their return migration pathbetween Alaska and spawning areas in the upper Fraser watershed (Figure 1, Figure 2).Given the diversity of Fraser sockeye stocks, virtually all of the harvests are classified as“mixed-stock” fisheries.Table 1 provides the annual estimates of the number of Fraser sockeye harvested by eachof the three major fishing sectors in Canada (First Nations, commercial, and recreational)and two distinct fishing areas in the US (Washington and Alaska). These catch estimateswere extracted from PSC annual reports because these reports are the only publishedsource of catch estimates for Fraser sockeye. Table 2 provides a summary of ourqualitative ratings for accuracy, precision, and reliability of the data used to generate thecatch estimates for the majority of the sockeye harvested in each fishery. For example, ifcatch estimates for seines were rated “Good” and seines catch the majority of thesockeye, the overall rating will be “Good” for that fishery. A quantitative assessment ofaccuracy was not possible because the true catch values are not known. Similarly, therewas insufficient information to quantitatively assess the precision of catch estimates. ForTable 2 and other similar summary tables in the report, we used the following qualitativeratingscales for our evaluations of data quality:Accuracy = the degree managers can be confident that the reported catch reflectsthe actual harvest (“Fair” = likely biased low in some or most years; “Good” =any bias is likely to be small; “Very Good” = complete enumeration of the catch).Precision = generally unknown for most fisheries, estimates of precision areprovided where available and where catch estimates are a complete count, theprecision rating was “High”).Reliability = the degree managers can rely on the catch estimates for in-seasonand post-season assessments. These ratings are similar to the ratings for accuracyexcept biased estimates that received a “Fair” rating for accuracy could receive a“Medium” rating for reliability if the direction of the bias is known.Since 2001, the overall ratings for Fraser sockeye catch estimates were: “Good” foraccuracy, “Unknown” for precision, and “Medium” for reliability (Table 2). The catch17