Many recreational fisheries are subject to varying degrees of catch‐and‐release fishing through regulations and conservation‐minded anglers. Clearly, releasing a proportion of the catch improves conservation of the fishery, yet it is not clear how the released catch contributes to angling quality. If fish change their behavior to lower their individual catchability after they have been caught, then angler catch rates may not be proportional to fish density. Therefore, even catch‐and‐release fisheries could exhibit poor angling quality if there is sufficiently high angler effort. We tested this idea by experimentally fishing five small lakes that contained rainbow trout Oncorhynchus mykiss in the interior of British Columbia. We found that with sustained effort of 8 angler‐hours · d−1 · ha−1 and complete release of the catch, catch rates quickly dropped within 7–10 d. Given the individual capture histories of tagged fish, the most parsimonious catchability model incorporated learning and heterogeneity into intrinsic catchability. The best‐fit parameter values suggest that the population contained a group of highly catchable fish that were quickly caught and then learned to avoid hooks. There was a seasonal decrease in catchability that was independent of angling; however, it was not sufficient to explain the data. Our results indicate that catch rates may decline because of high angling effort even when the number of fish remains constant. Therefore, management goals that go beyond conservation issues and attempt to maximize angler satisfaction must account for effort density on a recreational fishery.

Genetics-based approaches have informed fisheries management for decades, yet remain challenging to implement within systems involving recently diverged stocks or where gene flow persists. In such cases, genetic markers exhibiting locus-specific (‘outlier’) effects associated with divergent selection may provide promising alternatives to loci that reflect genome-wide (‘neutral’) effects for guiding fisheries management. Okanagan Lake kokanee (Oncorhynchus nerka), a fishery of conservation concern, exhibits two sympatric ecotypes adapted to different reproductive environments; however, previous research demonstrated the limited utility of neutral microsatellites for assigning individuals. Here, we investigated the efficacy of an outlier-based approach to fisheries management by screening >11 000 expressed sequence tags for linked microsatellites and conducting genomic scans for kokanee sampled across seven spawning sites. We identified eight outliers among 52 polymorphic loci that detected ecotype-level divergence, whereas there was no evidence of divergence at neutral loci. Outlier loci exhibited the highest self-assignment accuracy to ecotype (92.1%), substantially outperforming 44 neutral loci (71.8%). Results were robust among-sampling years, with assignment and mixed composition estimates for individuals sampled in 2010 mirroring baseline results. Overall, outlier loci constitute promising alternatives for informing fisheries management involving recently diverged stocks, with potential applications for designating management units across a broad range of taxa.

Optimization of stocking practices regarding release size and density requires an understanding of how dynamic ecological and angler effort processes interact. We used experimental data on size and density‐dependent fish recruitment processes and combined these with empirical fishery data to model the outcome of different stocking strategies. The model is based on the British Columbia Rainbow Trout Oncorhynchus mykiss fishery, which is an open‐access recreational fishery where fish recruitment is entirely derived from hatchery production. Under this scenario, changes to stocking practices primarily influence angler effort densities, whereas angling quality, defined as a function of catch rate and fish size, remain relatively constant. In light of this, we suggest that the primary performance measure for open‐access recreational fisheries management be sustainable angler effort. We modeled the effort response to stocking changes under contrasting biological (lake productivity) and fishery (remoteness, harvest regulations) characteristics. Lake‐specific effort is maximized by stocking larger fish into productive lakes that are harvested. However, the strategy to maximize regional effort across multiple lakes was dependent on the ratio of hatchery production to total lake area and the mix of individual lake productivities within the total lake area.Received July 10, 2012; accepted March 10, 2013

Understanding how environmental productivity and resource competition influence somatic growth rates and plasticity in life-history traits is a critical component of population ecology. However, evolutionary effects often confound the relationship between plasticity in life-history characteristics and environmental productivity. We used a unique set of experimentally stocked populations of rainbow trout (Oncorhynchus mykiss) to empirically test predictions from life-history theory relating to patterns in immature growth rates, age- and size-at-maturity, and the energy allocated into reproduction across climatic and fish density gradients. Our results support theoretical predictions that plasticity in life-history characteristics is a function of environmental variables. In particular, we demonstrate that immature growth rates are best explained by climatic and density-dependent competition effects and that age-at-maturity and the energy allocated to reproduction depends on juvenile growth conditions. Empirical evidence of these relationships helps to improve our understanding of optimal life-history strategies of fish populations.