Salmon hatchery return data, 1975-2016

This dataset contains salmon return data by release site to Alaska fisheries enhancement projects, as reported by operators. More details on this dataset can be found in the Alaska Fisheries Enhancement Annual Report, 2016 (http://www.adfg.alaska.gov/FedAidPDFs/RIR.5J.2017.04.pdf). This harvest data is simply how many fish were harvested by a hatchery operator in their harvest area, and is not necessarily the number of hatchery-origin fish in that harvest. The original data is contained in ADFG_Obtained_AKReturns.xlsx. The included RMarkdown script (Hatchery_returns_reformatting.Rmd) reformats these data, and assigns region information based on the release site used by the hatchery. The reformatted file is "hatchery_returns.csv". The "Project" column generally denotes the release site. "CatchType" indicates what kind of harvest project the harvested fish were a part of. This distinguishes both by sector (commercial, subsistence, sport fish), gear (for commercial sector fish), and fish caught for brood stock or cost-recovery. In some early years, the harvest was not broken out by gear, and only an estimate for generalized commercial catch was derived - these are assigned the CatchType of "commerical other." A CatchType of "other" indicates that the type of catch did not fit easily into the other categories. Negative numbers in the catch values for this dataset are real. Sometimes when a sample of fish is taken at the hatchery or the escapement to a system where a hatchery is located, not all the fish may originate from that hatchery. The fish may be wild fish from the system or hatchery fish from another hatchery. The negative numbers are there to reduce the total of hatchery fish that were counted in the brood stock or escapement by those non-hatchery fish, where non-hatchery fish are known to exist in the harvest.