Angler effort response to sterile rainbow trout stocking in small BC lakes

Abstract Angler effort responses to the stocking of sterile rainbow trout were evaluated using a historical data set consisting of 63,000 angler boat counts, which were used to develop indices of annual angler effort for 513 lakes representing 3396 lake-years of data over a period of 25 years. Included in this data set were 173 lakes that were supported by put-and-grow stocking of rainbow trout, and that received diploid (2n) stocking in earlier years and triploid (3n) stocking in later years. A stocking-size-dependent, ploidy-independent, growth and survival model was used to estimate the number of fish available to anglers one and two years post-stocking. Following a change to triploid stocking, boat counts increased by 31%, with larger increases in more remote Regions. Boat counts declined through time by 0.988x/yr, but with substantial variation among years (SD = 0.124). A principal component synthesized from four correlated variables (license cost, license sales, gas price, Can$:US$) explained 35% of the residual variation in boat counts among years. The boat count response to fish abundance was positive for rainbow trout, at 0.20x of the proportional change in abundance. An index of size-and-quota regulation intensity ranging from 0 (general restrictions only) to 1 (catch and release only), indicated that boat count response was positive, at 1.17x of the proportional increase in regulation intensity.