Consequences of fish stocking density in a recreational fishery

Density-dependent processes resulting from fish stocking were demonstrated to have a significant impact on recreational fishery performance, and this case study will be of use to guide fish stocking decisions in other fisheries. We evaluated a put-grow-and-take lake fishery stocking program for Chinook salmon (Oncorhynchus tshawytscha) located in south-western Victoria, Australia. We hypothesised that recreational fishery performance would show significant density-dependent relationships with fish stocking. To test this hypothesis, we used Wald F tests in a general linear regression model to evaluate relationships between a long-term historical fish stocking program and fishery performance, including angler and net catch rates and weight, length, and condition of caught fish. Our results yielded (i) significant positive relationships between angler and net catch rate of Chinook salmon with the number of Chinook salmon stocked in the same year and (ii) significant negative relationships between the weight of angler-caught Chinook salmon with both the number of Chinook salmon stocked in the same year and total number of fish stocked (apart from Chinook salmon) over the previous three year period.