Angler Catch Rates Research Articles

Effect of stocking on brown trout angling catch rates in the Czech Republic during 1996–2018

AbstractWhen investigating potential causes of apparent declines in European brown trout angling catch rates over recent decades, fisheries management procedures are rarely considered. Using a 20‐year dataset of brown trout stocking and angling catch rates, we found a significant decline in brown trout angling catch rates in streams of East Bohemia, Czechia, were well predicted by a reduction in the number of brown trout stocked at catchable size (i.e. age‐3+). Increased stocking of smaller sized brown trout, and recent sporadic efforts to stock large brown trout, had no effect on catch rates. Our findings suggest that brown trout catch rates were related to ‘put‐and‐take’ stocking, in which non‐native rainbow trout gradually replaced brown trout in both stocking and catches. Our study stresses the importance of considering historical fisheries management, a sometimes‐neglected factor, when studying angling catches of economically important species.

Counteracting effects of “hook avoidance” and “hook habituation” on angler catch rates in a catch‐and‐release fishery

AbstractCatch‐and‐release (C&R) angling is often used to maintain high catch rates but fish vulnerability to capture may decrease following hooking, thereby decreasing angler catch per unit effort (CPUE) (hyperdepletion). To determine if fish post‐capture response affected recapture probability and population‐level CPUE, individual capture histories of Largemouth Bass in two lakes were compared before and after doubling angling effort in a Before‐After Control‐Impact (BACI) analysis. Previous capture and day‐of‐season both affected recapture probability. Counteracting effects of previous capture and reduced late‐season catch rates caused no hyperdepletion of angler CPUE. Our results highlight the complexity of fish behavioral responses to angling and suggest that hyperdepletion of angling catch rates may not be an issue in C&R fisheries.

Gafftopsail Catfish in Texas estuaries: Population trends and ecosystem implications

AbstractObjectiveGiven the limited information on population dynamics of Gafftopsail Catfish Bagre marinus in the western Gulf of Mexico, the objectives of this study were to determine the status of this species in Texas estuaries by assessing trends in relative abundance, length, and habitat preferences from fishery‐independent trawl (juvenile) and gill‐net (adult) data, as well as angler harvest trends from fishery‐dependent creel surveys collected in all Texas estuaries.MethodsFishery‐independent and ‐dependent monitoring data were collected by the Texas Parks and Wildlife Department in all major bay systems of the Texas coast from 1983 to 2022. Linear trend analysis was used to assess trends across the full time series and all major bay systems for both juvenile and adult specimens and for total recreational harvest. Boosted regression tree analysis was used to assess habitat preference for both juveniles and adults.ResultBoth juvenile and adult catch rates consistently increased in most Texas estuaries, with the most extreme increases occurring in central Texas coast estuaries beginning in the early 2000s. During the same time frame, mean lengths of adult specimens significantly decreased in many of the same estuaries. Habitat suitability analysis suggested that Gafftopsail Catfish were primarily influenced by salinity, though they still exist across a very broad range of salinity conditions. Angler catch rates showed some localized patterns of increasing or decreasing trends, though they generally did not follow fishery‐independent trends for most estuaries.ConclusionThese trends interpreted in the context of the known trophic role of Gafftopsail Catfish imply the potential for larger ecosystem‐level effects on both prey organisms and competitors. A more thorough awareness of these trends and potential interactions should help fisheries managers operate in an ecosystem‐based context when investigating population dynamics and recommending management strategies.

Do angler catch and harvest rates differ between open water and ice anglers in Wisconsin?

Understanding seasonal differences in species-specific vulnerabilities to recreational angling can be important for informing sustainable fisheries management practices, like fishing seasons or season-specific regulations. However, comparisons of angler catch and harvest rates among seasons with disparate modes of fishing, like open water and ice angling in north-temperate lakes, are lacking. We used all available Wisconsin Department of Natural Resources point-intercept creel survey data during 1990–2020 to test for seasonal differences in the fisheries for five species targeted by open water and ice anglers in Wisconsin, USA, lakes (black crappie Pomoxis nigromaculatus, bluegill Lepomis macrochirus, northern pike Esox lucius, walleye Sander vitreus, yellow perch Perca flavescens). Specifically, we tested for: 1) species-specific differences in mean open water versus ice angling catch and harvest rates; 2) trends in species-specific mean open water versus ice angling catch and harvest rates during 1990–2020; and 3) monthly patterns in mean species-specific angler effort and catch rates. Mean angler catch rates of the five study species were significantly higher during the open water season and mostly temporally stable – only black crappie and bluegill open water catch rates and black crappie ice season catch rates significantly increased during 1990–2020. Mean angler harvest rates were significantly higher in the open water season for black crappie, bluegill, and walleye. Harvest rates were significantly higher during the ice season for northern pike and did not differ between seasons for yellow perch. Harvest rates were mostly temporally stable across species, although harvest rates declined for bluegill ice fishing and yellow perch in both seasons. Species-specific angler effort and catch rates mostly corresponded with seasonal (spring/early summer) vulnerabilities of our study species, although higher winter effort and catch rate patterns for northern pike and yellow perch may suggest unique harvest preferences for those species. Our results suggest that ice angling should not be assumed to have a negligible influence on fish populations in north-temperate lakes, fisheries-dependent and -independent monitoring data should be jointly considered when assessing fish population status, research on the human dimensions of ice fisheries is critically needed, and angler knowledge of seasonal fish vulnerabilities are generally coupled with higher fish catch rates.

Effects of elevated water temperature on cutthroat trout angler catch rates and catch‐and‐release mortality in Idaho streams

AbstractThe concern is growing that angling may need to cease at elevated summer water temperatures to protect salmonid populations. Cutthroat Trout Oncorhynchus clarkii in streams were caught, marked and released using artificial dry flies at temperatures from 13.5 to 25.7°C to evaluate whether subsequent recapture with backpack electrofishing (an index of relative survival) was reduced when the water temperature was elevated at the time of landing, and to evaluate the effect of water temperature on angler catch rates. The electrofishing recapture rate of marked fish (i.e. relative survival) declined as water temperature increased, from 0.58 for fish landed at <21°C to 0.35 at 21–23°C and 0.17 at >23°C. However, angler catch declined similarly as water temperature increased, from 5.2 fish/h at <21°C to 4.1 fish/h at 21–23°C and 1.2 fish/h at >23°C. After accounting for both declines, fish mortality/angler might be higher at cooler water temperatures than at warmer temperatures. Therefore, inhibiting fishing at elevated water temperatures may not benefit trout populations any more than at cooler temperatures.

Ice fishing reveals size structure but not abundance of Eurasian perch in small boreal lakes

AbstractManagement of inland recreational fisheries would benefit from stock abundance and size structure data. Feasibly standardised angling methods such as ice fishing could produce representative catch‐per‐unit‐effort (CPUE) information on the abundance of different‐sized fish in small lakes. Here, we first used standard Nordic multimesh gillnets to obtain number‐per‐unit‐effort (NPUE), biomass‐per‐unit‐effort (BPUE) and size structure data on Eurasian perch (Perca fluviatilis) stocks in 11 small boreal lakes in summer. Second, the same lakes were ice‐fished by voluntary anglers using a pre‐defined, loosely standardised protocol to obtain angling‐based NPUE, BPUE, and length frequency distributions. Effects of environmental variables such as water oxygen concentration and light penetration on angling catch rates were controlled statistically. Neither perch Nordic gillnet NPUE nor BPUE corresponded to ice‐fishing CPUEs. However, the length distribution of the catch did not differ between methods. Our results imply that traditional ice fishing applying natural baits is relatively unselective for fish size and could produce valid length‐based indicators for management purposes while angling CPUE was poorly related to Nordic gillnet CPUE.

Effect of Bag Limits on Angler Harvest, Catch Rates, and Satisfaction at Put‐and‐Take Community Pond Fisheries

AbstractCommunity pond fisheries are valuable recreational resources for anglers because of their ease of access and often‐regular stocking frequency. Effective management of these fisheries requires an understanding of how bag limits, stocking frequency, stocking density, and angler effort affect angler satisfaction and catch rates. We released tagged, catchable‐sized Rainbow Trout Oncorhynchus mykiss and conducted creel surveys at Idaho ponds with either two‐ or six‐trout daily bag limits (hereafter, “two‐trout ponds” and “six‐trout ponds”) to evaluate whether the bag limit affected catch rates between stocking events. Angler catch rates averaged 0.53 fish/h at two‐trout ponds and 0.76 fish/h at six‐trout ponds. Catch rates declined in the days after trout stocking but did so at similar rates in ponds with different bag limits. Catch rates were negatively affected by air temperatures throughout the study. Fifty‐four percent of anglers reported being somewhat satisfied or very satisfied with their fishing experience at two‐trout ponds compared to 64% of anglers at six‐trout ponds. This measure of satisfaction was positively related to an individual's catch rates. Despite the threefold difference in daily bag limits, 57% of anglers harvested two or fewer fish at six‐trout ponds. Angler‐reported tags indicated that stocked trout remained at large longer (mean = 29 d) in two‐trout ponds compared to six‐trout ponds (mean = 17 d). Tag returns suggested that on average, total use (harvested trout plus caught‐and‐released trout) was much higher at six‐trout ponds (57%) compared to two‐trout ponds (34%). Although the recruitment potential and accessibility of community ponds are well known, our results suggest that catch‐related outcomes of community pond management are a complex result of environmental factors, fisheries regulations, and fish stocking variables.

Species differences, but not habitat, influence catch rate hyperstability across a recreational fishery landscape

In commercial and recreational fisheries, catch rate is often assumed to be proportional to stock size and is used by managers and fishers as an indicator of fishery sustainability. If catch rate is proportional to stock size, it can signal a decline of stocks and managers can impose restrictive harvest policies or recreational anglers can move to a new system and allow the over-exploited system to rebound. A growing literature has documented catch rates remaining high even as fish stocks decline (i.e., hyperstability of catch rates) leading to delayed management intervention and overexploitation. Although recent evidence has indicated the presence of hyperstability of catch rates in recreational fisheries, whether hyperstability differs across species or system types remains unknown. To investigate whether catch rate hyperstability varies amongst species or systems, we first tested whether electrofishing catch per unit effort (efCPUE) was an appropriate proxy for true abundance. We then compared the relationship between angler catch rate and fish abundance for common freshwater sport fishes across gradients of habitat availability. We found significant differences in the strength of hyperstability amongst species. We did not identify a consistent influence of habitat on hyperstability of catch rates. Angler preferences and behavior may explain some of the variance in non-proportional catch rates. Future research investigating angler behavior, population size structure, and population dynamics in these systems may identify key interactions that create differences in vulnerability to population collapse.

Fish and Prey Resources in Reservoir Coves with and without Offshore Artificial Habitat Structures

Artificial habitat structures are used to mitigate habitat loss within aquatic ecosystems and to increase angler catch rates; however, the potential trophic outcomes of concentrating fish at structure additions are rarely evaluated. We compared fish and fish prey assemblages between reservoir coves with and without newly added offshore habitat structures (PVC cubes enclosing 2.25 m3). Further, we tested whether offshore habitat additions changed fish assemblage and abundance in littoral habitats of treated coves. Coves with offshore structures had higher concentrations of fish and an assemblage structure dominated by Pomoxis and Lepomis species at offshore sites compared to coves without offshore structures. There was no evidence for an effect of offshore structures on fish relative abundance and assemblage structure in nearby littoral habitats. Zooplankton and benthic macroinvertebrate abundances did not change because of the addition of habitat structures. Lack of a response of lower trophic organisms may be due to low predation mortality or else losses to predation are replaced by increased prey production or immigration at the offshore structures. Our results indicated that artificial structures effectively concentrated fish, but increases in fish density may be partitioned among newly available structure in offshore habitats and existing structure within littoral habitats. Future studies are needed to test for a relationship between foraging space and food resources provided by artificial habitats, which may be useful for optimizing the number, size, and material composition of structures used in habitat enhancement programs.

A comparison of fish catch rates among local, non-local, and non-resident anglers of three northern Wisconsin lakes

Understanding influences of angler proximity on fisheries resources, in the distances anglers are willing to travel for angling opportunities and their success rates after they arrive, could influence fisheries resiliency and management applications. The Wisconsin Department of Natural Resources, Northern Highland Fishery Research Area (NHFRA), Vilas County, Wisconsin maintains a compulsory creel census that collects angler ZIP code information and species-specific angler catch rates from all visiting anglers. We used NHFRA angler ZIP code data from 2014 to 2019 on Escanaba, Nebish, and Pallette lakes to construct anglershed maps (i.e., highest density areas from which anglers traveled to fish the lakes) for muskellunge (Esox masquinongy), smallmouth bass (Micropterus dolomieu), walleye (Sander vitreus), and yellow perch (Perca flavescens) to better understand angler travel patterns. We then tested for differences in species-specific catch rates among local (from counties surrounding or adjacent to the lakes, <100-km away), non-local (from counties in southern Wisconsin, >350-km away), and non-Wisconsin resident anglers. We hypothesized that local anglers would have higher overall species-specific catch rates due to proximity to the lakes and local knowledge than non-local or non-resident anglers. Anglersheds showed high use of the lakes by non-local anglers associated with major population centers in southern Wisconsin (Dane and Milwaukee counties) and adjacent states (Illinois and Minnesota). Species-specific catch rates did not differ appreciably among local, non-local, and non-resident anglers. Our results suggest that local knowledge may not be a good indicator of fishing trip success or elevated catch rates. Technology and angler information sources may level the playing field for anglers resulting in the homogenization of catch rates. Therefore, distance from a fishery may not aid in strengthening fisheries resilience.

Evaluation of Walleye Minimum Length Limits with Changing Water Regimes in the Great Plains

AbstractAbove‐normal precipitation in the 1990s resulted in new waters and Walleye Sander vitreus fisheries across northeastern South Dakota. Concerns with overharvest led to the implementation of a Walleye minimum length limit (MLL) on many new fisheries, but over time most of the MLLs were removed. We were interested in knowing why the MLLs failed. We compared Walleye gill‐net data and angler creel data under rising and declining water regimes and between periods with and without an MLL regulation in two new waters (Bitter Lake and Waubay Lake). We also assessed Walleye annual recruitment and growth patterns and examined if water regimes, MLLs, or Walleye recruitment were potential drivers of Walleye relative abundance, growth, and size structure. Few differences were found across water regimes and between periods with and without an MLL. At Bitter Lake, significant differences were identified across water regimes for the number of age‐3 Walleyes per gill net, Walleye proportional size distribution of preferred length (PSD‐P), angling pressure, and angler catch rates of Walleyes. Walleye relative weight and PSD‐P significantly differed between water regimes at Waubay Lake. Mean length at capture for age‐3 Walleyes and proportional size distribution were significantly different between periods having an MLL and no MLL at Bitter Lake. At Waubay Lake, Walleye gill‐net CPUE (number/gill net) and PSD‐P significantly differed between periods with and without an MLL. Water regimes, MLL, and Walleye recruitment were not identified as strong drivers of Walleye population characteristics. Recruitment was variable in each lake (Bitter Lake age‐3 CPUE CV = 148%, Waubay Lake age‐3 CPUE CV = 166%), with occasional strong cohorts recruiting. We believe recruitment dynamics influenced Walleye abundance and growth, which led to the removal of MLLs from each lake. Knowledge concerning Walleye population recruitment dynamics and growth is important when implementing MLLs and evaluating their effectiveness.

Angling of hybrid sunfish from a hatchery pond with potential implications for community fisheries

Hatcheries are frequently called upon to produce catchable-sized fish for stocking community fishing ponds. Desirable attributes of fish selected for stocking into community ponds are that they are easy to produce in a hatchery system to sizes anglers are interested in catching and they provide anglers with high catch rates once stocked. Hybrid sunfish [male Bluegill (Lepomis macrochirus) × female Green Sunfish (L. cyanellus)] have attributes that potentially make them attractive for use in community fishing ponds. We assessed initial angler catch rates of 100 stocked hybrid sunfish in a 0.12-ha hatchery pond and after being subjected to angling (four, 1-hr catch-and-release fishing events with five anglers). We also investigated whether catch rates would change following a supplemental stocking of an additional 100 hybrid sunfish (four, 1-hr catch-and-release fishing events with five anglers). The anal fin of each fish in the second stocking was hole punched to differentiate them from those of the first stocking and fish caught by anglers were hole punched in the caudal fin each time they were caught before being released back into the pond. Angler catch rates were highest during initial fishing events that followed stocking (9.2 fish/angler hr and 18.0 fish/angler hr) and substantially declined in subsequent events (≤3.4 fish/angler hr). Catches of the newly stocked fish and previously stocked fish contributed to the high catch following the supplemental stocking. Most (80 %) of the fish were caught in the first 30 min of each event and 45 % were caught during the first 10 min. Anglers were able to catch 88 % of the fish from the first stocking and 67 % from the second stocking at least once. No mortality occurred during the study as all fish were recovered when the pond was drained. Our results suggest that hybrid sunfish will potentially provide high initial catch rates following stocking into community ponds, but managers should expect reduced catch rates following initial fishing even without harvest. Additional stocking will be needed to provide periodic increases in angler catch rates even without harvest.

Comparative angler catch rates of native versus alien piscivorous fish in an invaded river fishery

Recreational angling is a major introduction pathway for large-bodied alien fishes into freshwaters, where the fish are released to enhance angling success and increase angler satisfaction, despite this often resulting in invasive populations. There is a thus a need to understand the role of these alien species in angler catches to enable more informed risk-based decisions to be made on future releases. In England, the invasive, piscivorous pikeperch Sander lucioperca has been present in rivers since the 1960s. Anglers target invasive pikeperch in fisheries where the native piscivorous pike Esox lucius is also present; this includes two rivers in the lower Severn basin, western England (main River Severn and Warwickshire Avon). To assess the contributions of invasive pikeperch to angler catches, the aim here was to compare their catches with those of native pike in the lower Severn basin in relation to angling effort and methods, abiotic conditions, and fish size. In 307 angling sessions across 16 anglers where at least one fish was captured, 428 pike and 266 pikeperch were captured. In a sub-set of data from six anglers who submitted catch returns that included non-capture sessions, 78 % of sessions resulted in the capture of at least one pike or pikeperch. Catch rates of pike were significantly higher than pikeperch in the main River Severn but not the Avon. Captured pike were significantly larger than pikeperch, but pikeperch were larger relative to the maximum size each species reaches in England. Lures generally captured more pike than any other method, with these fish tending to be smaller than those caught on other methods; these patterns were not evident in pikeperch. Both species were captured across a broad range of river flow conditions (Q6 to Q99). Only 19 % of successful angling sessions resulted in the capture of both species, suggesting some species selectivity by anglers. These results emphasise that alien fish species can provide important angling resources in recreational fisheries, although management decisions on future introductions should still consider their ecological risks.

Are Alberta’s Northern Pike Populations at Risk from Walleye Recovery?

AbstractAngling catch rates of Walleye Sander vitreus in many lakes across Alberta have increased dramatically in the past 20 years, following their collapse and then recovery after implementation of restrictive harvest regulations. With increased abundance, some anglers are concerned that Walleyes may negatively affect abundance of Northern Pike Esox lucius. To address this hypothesis, we looked at net catch data for each species from 352 surveys in 129 lakes across Alberta between 2000 and 2017. Results were equivocal. Netting data indicated that low‐density Northern Pike populations were not associated with high densities of Walleyes when grouped categorically. However, mixed‐model quantile regression did support a negative relationship for the two species, but the mechanism is unclear and the strength of the interaction is weak in most cases. In few lakes (≤10%), potentially acceptable reductions in Walleye densities may produce meaningful increases in Northern Pike but uncertainty is substantial. Future Walleye harvest experiments to reduce uncertainty and establish causation are warranted only if Northern Pike are already at moderate to high densities and large reductions in Walleyes (≥75%) are acceptable. For these reasons, increased Walleye harvest is not supported as a management tool for increasing Northern Pike populations or enhancing angler catch rates in Alberta.

From scientific obscurity to conservation priority: Research on angler catch rates is the catalyst for saving the hump‐backed mahseer Tor remadevii from extinction

Abstract The mahseer (Tor spp.) fishes of South and Southeast Asia are iconic megafaunal species that are highly valued by recreational anglers. Knowledge on their populations is limited owing to the challenges associated with sampling these large‐bodied fishes (&gt;50 kg) in remote monsoonal rivers. Despite its global iconic status among recreational anglers, the hump‐backed mahseer of the Cauvery River (South India) lacked a valid scientific name and was on a trajectory towards extinction until its rapidly declining population status was established by analyses of angler catch records. Angling records from 1998 to 2012 showed that mahseer catch rates had increased in this period. The resulting publication in Aquatic Conservation (AQC) highlighted the positive role of catch‐and‐release angling in providing information on data‐poor species. However, further analyses showed that these catches comprised not one but two distinct phenotypes. Before 1993, all mahseer captured were hump‐backed; since then, a blue‐fin phenotype appeared in catches and subsequently dominated them. These results triggered further studies indicating that the hump‐backed mahseer was the endemic Tor remadevii and that the blue‐fin was the invasive Tor khudree, introduced in 1976 and then stocked periodically from hatcheries. The initial AQC publication successfully demonstrated the high value of organized angling as a monitoring tool for data‐poor fishes and its application to assessing the temporal population patterns of large‐bodied fishes in monsoonal rivers. It was also the catalyst for initiating subsequent studies on T. remadevii that, together, enabled its recent assessment as ‘Critically Endangered’ on the International Union for Conservation of Nature (IUCN) Red List. In the absence of the AQC paper, and the subsequent studies that it triggered, it is highly probable that the species would have remained on a trajectory towards rapid extinction. Instead, the first major steps to safeguarding its future have been taken.

Fishing efficiency of competitive largemouth bass tournament anglers has increased since early 21st century

AbstractTournament fishing has risen in popularity over the last half a century. As such, social and financial incentives combined with technological advancements are expected to drive changes in angler's capacity to exploit tournament‐eligible fish stocks, as has been observed in commercial fisheries. The aim of this study was to quantify temporal trends in angler efficiency and their ability to exploit a given fish stock relative to effort in largemouth bass fishing tournaments. A collective analysis across seven Illinois reservoirs comparing change through time in angler catch rates and relative population abundances indicated that angler efficiency has generally improved through time. For the decade from 2005 to 2015, a greater than threefold increase in the efficiency of anglers to exploit a static population of largemouth bass was estimated. Anglers have become more efficient at exploiting populations, which is likely to influence management decisions in the future, particularly in harvest‐orientated fisheries and those reliant upon fishery‐dependent surveys.

Leveraging public harvest to reduce invasive hybridization in Yellowstone National Park: field identification and harvest of cutthroat\xa0\xd7\xa0rainbow trout hybrids

Leveraging public harvest can be a cost-effective invasive species management tool, but target taxa must be correctly identified and removed at rates that achieve biological objectives. We explored the potential role of recreational anglers to curtail expanding hybridization between invasive rainbow trout (Oncorhynchus mykiss; RT) and native Yellowstone cutthroat trout (O. clarkii bouvieri; YCT) in the Lamar River watershed in Yellowstone National Park. We sought to (1) develop a hybrid identification key that could be used by anglers and (2) estimate angler participation, catch, and potential exploitation rates. We assessed seven morphological features of trout in the field (n = 251, 15 locations) and collected fin clips to estimate RT ancestry proportion using genetic analysis. An identification key was built using recursive partitioning to objectively distinguish YCT from RT and hybrids. A single-choice dichotomous key (white pelvic fin tip present/absent) correctly classified 93% of fish as native (YCT) or containing RT ancestry (RT or hybrid). Success increased to 97% when a second criterion was added (head spot count ≥ 6). Using angler surveys (2013–2017), we estimated that 10,000 anglers catch 50,000 trout annually. In a popular road-accessible area, most trout are probably caught and released ~ 5 times each year. The combination of high angler participation, substantial annual catch, and an accurate and easy to use identification method indicate that leveraging public harvest is a promising management tool. Invasive hybridization is a global conservation issue threatening many native taxa; this case study highlights some factors for resource managers to consider prior to implementing public harvest regulations and the benefits of standardized keys to distinguish hybrids in the field.

Experimental demonstration of catch hyperstability from habitat aggregation, not effort sorting, in a recreational fishery

The relationship between angler catch rates and fish abundance can contribute to or hinder sustainable exploitation of fisheries depending on whether catch rates are proportional to fish abundance or are hyperstable. We performed a whole-ecosystem experiment in which fish abundance was manipulated and paired with weekly angler catch rate estimates from controlled experimental fishing. Catch rates were hyperstable (β = 0.47) in response to changes in fish abundance. By excluding effort sorting (i.e., catch rates remaining high because less skilled anglers leave the fishery as abundance declines), our experiment isolated the influence of fish aggregation as a driver of hyperstability. Spatial analysis of catch locations did not identify clustering around specific points, suggesting that loose aggregation to preferred habitat at the scale of the entire littoral zone was enough to maintain stable catch rates. In our study, general, non-spawning, habitat preferences created loose aggregations for anglers to target, which was sufficient to generate hyperstability. Habitat preferences are common to nearly all fishes and widely known to anglers, suggesting that many harvest-oriented recreational fisheries can be expected to exhibit hyperstability.

Influence of Population Density and Length Structure on Angler Catch Rate in Kokanee Fisheries

AbstractManagement agencies are often charged with providing fisheries that lead to angler participation. Catch rate is one of the primary drivers of angler participation but can be influenced by a suite of factors, including population structure (e.g., density and size structure). The complexity of understanding how population structure influences angler catch rate is typified in kokanee Oncorhynchus nerka fisheries. Previous research suggests that angler catch rates of kokanee are positively influenced by fish density and total length. However, that research was based on data collected using size‐selective midwater trawls. Due to the potential limitation of previous research, we sought to (1) understand the relative bias of midwater trawls and gill nets for describing the size structure of kokanee available to anglers and (2) re‐evaluate the influence of fish density and fish length on angler catch rates in kokanee fisheries. Midwater trawl, gill‐net, and creel data were collected on five prominent kokanee fisheries throughout Idaho in 2016 and 2017. Catch composition and percent overlap of midwater trawls, gill nets, and angler‐caught fish were compared to understand the efficacy of midwater trawls and gill nets for representing the size structure of kokanee available to anglers. In addition, the influence of kokanee density and length on angler catch rates was evaluated. Midwater trawls primarily sampled small kokanee (&lt;330 mm) and exhibited little overlap with angler‐caught fish, whereas gill nets sampled more large fish (&gt;330 mm) and exhibited higher overlap with angler‐caught fish when compared to midwater trawls. Fish length was not positively associated with angler catch rates. However, fish density exhibited a positive relationship with angler catch rates. Our results highlight the importance of gear choice for understanding how kokanee populations function and elucidate the tradeoffs associated with population density, fish length, and resulting kokanee fisheries.

Influence of Largemouth Bass Behaviors, Angler Behaviors, and Environmental Conditions on Fishing Tournament Capture Success

AbstractTournament anglers typically possess extensive knowledge of the habitat and seasonal movement of their targeted species. While fish–angler behavioral relationships are critical to understanding fish catchability, few studies have assessed how fish behavior influences their vulnerability to capture by tournament anglers. Our objectives were to determine if Largemouth Bass Micropterus salmoides behavior, angler behavior, and environmental conditions affect tournament angler catch rate (CPUE) and Largemouth Bass capture probability at fishing tournaments. Forty‐nine Largemouth Bass were tracked weekly using radiotelemetry during a 4‐month period. Five tournament anglers were also selected at weekly tournament events and tracked continuously using a handheld GPS unit. We quantified individual Largemouth Bass behaviors (home range, weekly movement rate, depth use, and spatial overlap with anglers), angler behaviors (depth use, angler movement rate), and environmental conditions (air and water temperature) and used these estimates as covariates in a multiple regression model to assess their effects on tournament CPUE and then used a multistate mark–recapture model to estimate Largemouth Bass capture probability at tournaments. Our results indicate that Largemouth Bass movement rate, angler fishing depth, and air temperature were highly correlated to tournament angler CPUE. Mark–recapture models also indicated that air temperature and angler–fish overlap were positively associated with Largemouth Bass capture probability while fish total length, home range, movement rate, and depth use were not successful in characterizing individual variation in capture probability. Our results indicate that Largemouth Bass that are encountered by anglers are more likely to be captured, whereas mismatches between angler and Largemouth Bass behavioral factors, including depth use and movement rates, may result in decreased tournament capture rates. Consideration and continued evaluation of the relationships between Largemouth Bass and angler behaviors and environmental variables is critical to fisheries management as tournament pressure paired with high capture probabilities and selective angling can have large‐scale population‐level impacts.