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The assessment of the stock status of inland artisanal fisheries is extremely difficult due to limited or absent historical data on catch, effort, or recruitment. Most of these fisheries are considered potentially overfished due to their "open‐access" nature and poor management. Alternately, fishing below maximum yield could cause a loss in potential yield as well as food supply for local communities. The Giant Cichlid Petenia splendida has been considered to be overexploited in Guatemala. Our objective was to measure fishing mortality using a passive tagging study with reward tags for the Giant Cichlid fishery in Lake Petén Itzá to explore the potential for overfishing. In total, 24% of the tags were returned, and the return rate increased with the value of the reward (~US$6, $12, $18, and $25). We explored two reporting rate scenarios. Exploitation rate was estimated as 0.36 when the reporting rate was 100% and 0.48 when the reporting rate was 75%. A sensitivity analysis for yield‐per‐recruit and spawning potential ratio models indicated that this fishery was below the maximum sustainable yield without recruitment overfishing risk under both scenarios; thus, more stringent regulations are not required at this time. Moreover, under a conservative scenario, exploitation rates could increase yield by up to 40% for fish over 240 mm, suggesting the potential for increased resource utilization without causing growth or recruitment overfishing, and should not exceed 60% with fish under 220 mm TL. This study provides a preliminary assessment of the size limit and harvest rate that can prevent overfishing of the Giant Cichlid. Similar tag reward methods can be effectively applied to assess artisanal fisheries. The underfished condition in this fishery demonstrates that open‐access fisheries are not always overexploited, and there is a need for a better understanding of local regulations' effectiveness and the role of social and economic factors influencing artisanal fisher behavior. [ABSTRACT FROM AUTHOR]

Understanding trends in abundance is important to fisheries conservation, but techniques for estimating streamwide abundance of cryptic fishes with strong habitat–abundance relationships are not well established and need further development. We developed techniques for addressing this need using the Harlequin Darter Etheostoma histrio, a small, cryptic freshwater fish associated with submerged wood in streams. Our objectives were to (1) determine how Harlequin Darter abundance and the amount of submerged wood were related at sampled sites and (2) use this relationship to estimate Harlequin Darter abundance at unsampled sites and extrapolate Harlequin Darter abundance estimates and associated uncertainty streamwide. We conducted a mark–recapture study to estimate abundance of Harlequin Darters in 25‐m stream reaches at 24 sites in Big Escambia Creek (BEC) and 18 sites in Pine Barren Creek (PBC) (Escambia River tributaries in northwestern Florida). The number of wood pieces (submerged wood ≥1.5 m long and ≥0.25 m in circumference) in both creeks was counted and mapped using side‐scan sonar and a geographic information system. Harlequin Darter and wood data were used in a Bayesian multinomial mixture model to estimate site abundance of Harlequin Darters, to determine the relationship between wood and Harlequin Darter abundance, and to extrapolate Harlequin Darter abundance streamwide. We found a positive relationship between wood and Harlequin Darter abundance in both creeks, and there were more wood pieces in PBC than in BEC. Streamwide abundance of Harlequin Darters was greater in PBC than in BEC. The extrapolated streamwide abundance estimates were 9,369 Harlequin Darters (95% credible interval = 6,668–13,402) in PBC and 7,439 Harlequin Darters (95% credible interval = 4,493–11,226) in BEC. Our methods effectively estimated abundance of a small, cryptic fish that uses complex wood habitat. In addition, our findings may assist in the conservation of the Harlequin Darter. [ABSTRACT FROM AUTHOR]

Angling for trophy Largemouth Bass Micropterus salmoides and Florida Bass M. salmoides floridanus supports popular fisheries, particularly in the southern United States, where conditions are favorable for growing large fish. Traditional standardized sampling gears, such as electrofishing and creel surveys, often prove ineffective at obtaining sample sizes that are adequate for assessing the quality and temporal trends in trophy fisheries. In this study, we assessed the trophy Florida Bass population in the newly impounded Calling Panther Lake (163 ha), Mississippi, by using a nontraditional, specialized angling technique, and we compared the results with data collected by the more traditional techniques of creel surveys and electrofishing. The specialized angling technique utilized a select few highly skilled and devoted anglers that targeted only the largest bass in the population. The specialized angling technique collected nearly 8 and 24 times more trophy Florida Bass (≥3.6 kg or ≥56 cm TL) than creel surveys and electrofishing, respectively. As a result, this was the only method that reliably collected enough trophy‐sized fish to estimate the population size in Calling Panther Lake. Mark–recapture data were used to estimate an abundance of 150 trophy Florida Bass (95% confidence interval [CI] = 118–206) in 2011 (density = 0.92 fish/ha; 95% CI = 0.73–1.26). The use of data collected by specialized anglers provided vital information for the trophy segment of this bass population, which is often difficult for fisheries managers to obtain with traditional techniques. [ABSTRACT FROM AUTHOR]

Fish stocking and harvest regulations are frequently used to maintain or enhance freshwater recreational fisheries and contribute to fish conservation. However, their relative effectiveness has rarely been systematically evaluated using quantitative models that account for key size‐ and density‐dependent ecological processes and adaptive responses of anglers. We present an integrated model of freshwater recreational fisheries where the population dynamics of two model species affect the effort dynamics of recreational anglers. With this model, we examined how stocking various fish densities and sizes (fry, fingerlings, and adults) performed relative to minimum‐length limits using a variety of biological, social, and economic performance measures, while evaluating trade‐offs. Four key findings are highlighted. First, stocking often augmented the exploited fish population, but size‐ and density‐dependent bottlenecks limited the number of fry and fingerlings surviving to a catchable size in self‐sustaining populations. The greatest enhancement of the catchable fish population occurred when large fish that escaped early bottlenecks were stocked, but this came at the cost of wild‐stock replacement, thereby demonstrating a fundamental trade‐off between fisheries benefits and conservation. Second, the relative performance of stocking naturally reproducing populations was largely independent of habitat quality and was generally low. Third, stocking was only economically advisable when natural reproduction was impaired or absent, stocking rates were low, and enough anglers benefitted from stocking to offset the associated costs. Fourth, in self‐sustaining fish populations, minimum‐length limits generally outperformed stocking when judged against a range of biological, social and economic objectives. By contrast, stocking in culture‐based fisheries often generated substantial benefits. Collectively, our study demonstrates that size‐ and density‐dependent processes, and broadly the degree of natural recruitment, drive the biological, social, and economic outcomes of popular management actions in recreational fisheries. To evaluate these outcomes and the resulting trade‐offs, integrated fisheries‐management models that explicitly consider the feedbacks among ecological and social processes are needed. [ABSTRACT FROM AUTHOR]

Abstract: Angling for adult black bass Micropterus spp. as they defend nests containing eggs or fry (i.e., bed‐fishing) has drawn concerns from fishery managers and anglers due to negative impacts on reproductive success. Research efforts, however, have failed to consider bed‐fishing scenarios other than male‐directed targeting, which may inaccurately reflect angler behaviors. To gain insights into the behaviors, motivations, and attitudes associated with bed‐fishing across a large extent of the global distribution of black bass, we surveyed tournament anglers from the southeastern United States and South Africa (where black bass were introduced in 1928). Responses from 440 black bass tournament anglers indicated that during the reproductive season nearly half of all anglers spent 50% or more of their time bed‐fishing and that larger, female fish were preferential targets. Overall, the responses from U.S. and South African anglers were very similar, but significant attitudinal differences were associated with the perceived impacts of bed‐fishing on adult reproduction and juvenile production. Our results suggest that there are commonalities among the preferences and behavior of anglers from disparate geographic regions, and we highlight the need for future research on the impacts of size‐ and sex‐selective bed‐fishing of basses. [ABSTRACT FROM AUTHOR]

Black bassesMicropterusspp. are the focus of extensive management efforts throughout North America, where they support a multibillion-dollar recreational sport fishery. Harvest rates in many bass fisheries have declined in recent decades, yet a growing number of studies have proposed that catch-and-release angling practices, such as bed-fishing in which anglers intentionally target bass while the fish are defending their nests, can decrease individual reproductive success. In response, management agencies have restricted fishing during the spawning period in some regions. We evaluated the impacts of catch-and-release bed-fishing on Florida BassM. salmoides floridanusnest success, reproductive success, production of fall recruits, and the number of parents that contributed to reproduction. Eighteen replicate populations simulating natural Florida lakes were established, and ponds were assigned either a bed-fishing (n= 10) or a control treatment (n= 8). Snorkel surveys were conducted throughout the spawning period to track nest formation and nesting success rates, and 10 months after establishment all ponds were drained, recruits counted, and fin clips collected for genetic parentage analysis. A series of candidate generalized linear mixed models were compared using Akaike’s information criterion and likelihood ratio tests to assess the relative importance of fishing treatment and year, along with other relevant variables in predicting nest success, recruitment, and reproductive success. We observed significant reductions in nest success rates (z= −2.13,P= 0.03) but not recruitment levels (z= −1.31,P= 0.19), in populations that were bed fished relative to control ponds. Capture history poorly predicted individual reproductive success and the number of adults that contributed to fall recruitment did not differ by treatment (χ2= 0.06,P= 0.81). Results from this study indicated that bed-fishing practices may have some impacts on individual nest success but did not influence recruitment or overall reproductive success of Florida Bass at the population level. Received October 5, 2016; accepted February 28, 2017 Published online July 5, 2017 [ABSTRACT FROM AUTHOR]

Black bassMicropterusspp. support popular freshwater sport fisheries in North America. Bass anglers commonly adopt catch and release as a conservation practice, and frequently over 75% of angled black bass are released back into the water. If fish survive the angling event, the practice of catch and release as an alternative to harvest reduces direct mortality, but it has the potential to affect the postrelease feeding behavior and survival of the fish. The act of lifting black bass for handling, hook removal, and photograph opportunities may cause stress and injury, and the degree of injury sustained could be influenced by fish size. Holding fish in a tilted grip by the jaw has raised concern among anglers about potential damage to jaw musculature and tendons, as they may not support the fish’s body weight out of water, particularly for trophy bass. We conducted an experiment with Florida Largemouth BassM. salmoides floridanusto evaluate the relative differences in survival, jaw mechanics, and feeding success after the use of three common handling treatments: (1) a vertical hold using a lip-grip device (vertical treatment); (2) a tilted, one-handed grip using only the lower jaw (horizontal treatment); and (3) two-handed support to the lower jaw and body (support treatment). The time taken by fish to regain equilibrium and resume normal swimming behavior after handling differed among the three treatments; the recovery period was shortest for fish in the support treatment (mean ± SD = 7 ± 10 s; vertical treatment: 33 ± 74 s; horizontal treatment: 12 ± 16 s). Minor injuries (e.g., abrasions and sores) and diseases (e.g., tumors and fungus) tended to increase after handling across the entire sample. Results suggested no evidence of handling-specific differences in fish feeding behavior, jaw adjustments, and mortality after release. However, based on our results, we recommend that anglers use two-handed support to handle Florida Largemouth Bass, thus minimizing the mean amount of time for an individual fish to regain equilibrium after an angling event. Received February 22, 2016; accepted October 7, 2016 Published online February 22, 2017 [ABSTRACT FROM AUTHOR]

Supplemental stocking of fingerling or advanced fingerling Largemouth BassMicropterus salmoidesis a common management strategy for augmenting natural production in low-recruitment systems. Few studies, however, have evaluated the impact of stocking adult bass taken from donor lakes. Over a period of 6 years, University of Florida researchers stocked Florida Lakes Griffin and Dora with 24,781 wild Florida BassM. s. floridanuscollected by electrofishing from other Florida lakes. During stocking years, stocked fish made up to 10% of the population in Lake Griffin and 27% in Lake Dora from electrofishing samples. However, 1 year after all stocked fish had been released, the proportion of stocked bass had declined to less than 5%, and 3 years after it had declined to less than 1%. We did not detect an increase in recruitment (catch of age-1 bass) following stocking, so any benefit from stocking was likely short-lived. We also could not conclude that stocking was responsible for increasing fishing effort because total fishing effort did not increase after stocking. As a result, no additive economic benefits could be attributed to the stocking program. During randomized electrofishing sampling, we collected 51 wild bass that had been released during the stocking program, and genetic analysis determined that two (3.9%) were hybrids and had alleles from nonnative Largemouth Bass. The extrapolation of these results estimated that almost 1,000 hybrids had been introduced into Lakes Griffin and Dora, which were historically identified to contain pure Florida Bass populations. Future wild bass stocking programs should include an appropriate study design for evaluating changes in fish populations, changes in the fishery, and economic consequences of stocking. Furthermore, a risk–benefit assessment should be completed before any stocking program is initiated, including consideration of any potential impacts on biodiversity. Received February 26, 2015; accepted January 6, 2016 Published online May 9, 2016 [ABSTRACT FROM PUBLISHER]

Fish populations that undergo heavy exploitation and those for which the act of fishing can influence individual brood success are at risk of recruitment effects due to angling. The angling of brood-guarding male black bassMicropterusspp. has been shown to decrease brood success, although there is no evidence that a loss of individual broods has population-level impacts. Therefore, some level of recruitment compensation may influence juvenile bass survival. We sought to measure recruitment compensation and the form of the stock–recruit relationship for a brood-guarding species, the Florida Largemouth BassM. salmoides floridanus(hereafter, Florida Bass). The study was conducted in four north-central Florida lakes during 4 years (2010–2013). We quantified adult stock density by using mark–recapture electrofishing surveys. The estimated broods produced in each spawning season, the number of those broods that were successful, and the age-1 recruit density were quantified via snorkel surveys. We evaluated three models for describing the effects of stock density or successful brood density on recruitment: a proportional (linear; i.e., no compensation) model, a Ricker (dome-shaped) model, and a Beverton–Holt (asymptotic) model. Recruit density was better indicated by the number of successful broods produced than by spawning stock density. Model comparisons indicated that the density-dependent models had the most support, whereas there was no apparent support for the proportional or density-independent model. The Ricker model had the most empirical support overall (estimated parameters:a= 2.2,b= 0.009). Our results indicate that the number of successful broods would have to fall below about 5 broods/ha to generate direct declines in observed average recruitment of Florida Bass. Received August 5, 2015; accepted December 9, 2015 Published online April 14, 2016 [ABSTRACT FROM AUTHOR]

Mortality after release can have a substantial impact on high-release recreational sport fishes, such as Largemouth BassMicropterus salmoides. However, little work has explored the cumulative impact of catch-and-release mortality at the population level. We used a combined telemetry–tag return approach to estimate all components of total mortality, including instantaneous natural mortality (M) and instantaneous fishing mortality (F), for Florida Largemouth BassM. salmoides floridanus(hereafter, Florida Bass) within a popular fishing lake in northern Florida. Fishing mortality was subdivided into harvest (FH), recreational catch-and-release (FR), and tournament catch-and-release (FT) components. Over 2 years, we monitored the fates of 181 Florida Bass that were tagged with high-reward external dart tags and internal radio transmitters. An additional 345 fish were tagged with variable-reward external tags. AnnualFHvalues were seasonal, with an increase inFHoccurring in the spring of both years;FHranged from 0.17 (SD = 0.04) in the first year to 0.60 (SD = 0.09) in the second year. Estimated meanFTranged from 0.04 to 0.07, and meanFRranged from 0.03 to 0.05. Estimates ofMwere also seasonal, with annualMranging from 0.29 (SD = 0.06) to 0.46 (SD = 0.09), and were within the expected range relative to other published estimates. Our results showed that although the total catch-and-release mortality (FRplusFT) was low in comparison with the high rates of harvest (FH) for this Florida Bass fishery, it still made up 21% of totalF. Our method combining passive tagging and telemetry tagging allowed for the estimation of all mortality sources, which can be important for high-release recreational fisheries in which harvest is not the only source of mortality. Received July 14, 2015; accepted December 7, 2015 Published online April 25, 2016 [ABSTRACT FROM AUTHOR]

Stocking evaluations for pellet-reared, advanced-fingerling Largemouth BassMicropterus salmoidesoften result in low contribution and survival, but little information exists on their survival and behavior soon after release. This study investigated the behavior and mortality of pellet-reared, advanced-fingerling (90–120 mm TL) Florida BassM. floridanusimmediately after they were stocked in Lake Carlton, Florida. A radiotelemetry experiment was conducted to compare initial movement, habitat use, growth, and mortality between stocked hatchery and wild fish. In year 1, we inserted radio transmitters into 50 hatchery fish; in year 2, we tagged 30 hatchery fish and 20 wild fish. All mortality we observed for hatchery fish (from both years) resulted from predation by fish and birds, and most occurred in the first 7 d after tagging. When compared directly with tagged wild fish (n= 20), tagged hatchery fish (n= 30) exhibited greater movement (75 and 124 m/d, respectively), greater proportion of locations offshore (8% and 23%, respectively), slower growth (1.73% and 0.41% of their body weight gained per day, respectively), and higher predation (47% and 0%, respectively). Results of this study suggest that pellet-reared, hatchery Florida Bass suffer more predation than wild bass of similar size initially following their release into the lake. Causes of predation could include less-developed antipredator skills and inefficiency in foraging observed through greater movement, as well as the use of offshore habitat and slower growth. We recommend research that investigates acclimating advanced-fingerling Florida Bass to predators and live prey before release to determine whether initial predation can be reduced after stocking. Received May 29, 2015; accepted December 4, 2015 [ABSTRACT FROM AUTHOR]

The Murray Cod Maccullochella peelii and Golden Perch Macquaria ambigua are important recreational species in Australia's Murray–Darling Basin (MDB); both species have declined substantially, but recovery is evident in some areas. Minimum length limits (MLLs)—implemented to ensure fish could spawn at least once prior to harvest eligibility—have increased three times in the past decade. We quantified variation in length at 50% maturity (LM50), age at 50% maturity (AM50), and von Bertalanffy growth parameters (k = Brody growth coefficient; L∞ = asymptotic length; t0 = theoretical age at zero length) of these species within two rivers and two reservoirs of the MDB; to investigate whether fish length is a suitable surrogate for AM50 in setting MLLs. Between 2006 and 2013, we collected 1,118 Murray Cod and 1,742 Golden Perch by electrofishing and gillnetting. Values of k and L∞ were greater for reservoir fish than for riverine fish. For both species, AM50 was generally greater in rivers than in reservoirs; for Murray Cod, LM50 was greater in reservoirs than in rivers. A yield‐per‐recruit model demonstrated that smaller Murray Cod MLLs would be required for rivers and that an MLL at or below 600 mm (the existing MLL) across all populations could lead to overfishing in some systems. The differences in growth rate and the onset of reproductive maturation between riverine and reservoir populations suggest that system‐specific regulations would be more effective at reducing the overfishing risk and meeting fishing quality objectives. Received August 18, 2014; accepted September 10, 2015 [ABSTRACT FROM AUTHOR]

Size‐at‐age information is critical in estimating growth parameters (e.g., the von Bertalanffy growth function [VBGF]) that are used to assess fish populations. Due to gear selectivity, single sampling methods rarely sample all ages or all sizes equally well. Most growth estimates rely on samples from a single gear or a haphazard combination of gears, potentially leading to biased and imprecise growth parameter estimates. We evaluated the efficacy of combining samples from two gears with different size selectivity to estimate VBGF parameters; we then applied that approach to a case study on the Lochloosa Lake (Florida) population of Black Crappies Pomoxis nigromaculatus. Simulated age‐ and size‐structured populations were randomly sampled with two gears characterized by different size‐selectivity curves (one gear was selective for smaller fish; the other was selective for larger fish). Maximum likelihood VBGF estimates obtained for each gear separately were compared with estimates from a combined VBGF fitted to data from both gears. In every simulated scenario, a combined‐gear approach reduced bias and increased precision for estimating the VBGF, but the gear‐specific proportions that improved VBGF estimates depended on size selectivity. The VBGF estimates for the Black Crappie population showed that the combined‐gear method yielded intermediate parameter values relative to single‐gear approaches based on (1) trawl sampling (fishery‐independent survey) and (2) angler harvest (as determined from carcass collections; fishery‐dependent data). Furthermore, the combined‐gear approach had greater precision in individual parameter estimates and much less variance than single‐gear approaches when estimating the VBGF. Combining data from two gears can increase sample representativeness, leading to improvements in VBGF estimation. Such approaches can reduce uncertainty in VBGF estimation and can provide insight into key demographic processes occurring in fish populations for which ontogeny and gear selectivity lead to imperfect sampling. Received January 22, 2015; accepted July 30, 2015 [ABSTRACT FROM AUTHOR]

Species-specific harvest regulations in recreational fisheries are commonly applied regionally to protect stocks from overharvest and satisfy a diverse set of anglers. While setting regulations is a complex task and may incorporate the best available social and biological information, fisheries managers commonly obtain directed fishing mortality estimates within a single lake and then assume similar rates among other systems when setting regional harvest regulations. Thus, there is a need to assess regional levels of fishing mortality for informed use of regionally applied regulations. We implemented a practical method for assessing catch and harvest for a recreational fishery across a broad spatial region. We used a passive tag-reward study design and a regional management regulation area for Florida Largemouth BassMicropterus salmoides floridanusin central Florida as our case study. The estimated fishing mortality rate included both harvest and deaths due to catch and release. We found overall regional fishing mortality for Florida Largemouth Bass in central Florida was relatively low. From the 247 dart tags returned, the mean annual instantaneous total fishing mortality rate was 0.11 (95% credible interval = 0.08–0.15). We also found fishing mortality rates did not vary with lake size or fish total length. Our study design did not provide mortality estimates for any specific lake due to a low number of tagged fish per lake, but the method could be used to elucidate the effectiveness of regulations that are applied at a regional scale. Received November 20, 2014; accepted March 31, 2015 [ABSTRACT FROM PUBLISHER]

Reduction in transmitter size used in telemetry studies have allowed researchers to tag and track fish that are much smaller than could have been tagged previously. Researchers seek information on juvenile or small fish movement, behavior, and survival to better understand recruitment processes. Juvenile or small-bodied fish that have been tagged have an increased risk of predation, which results in transmitters being consumed. Knowledge about radio transmitter accumulation in a predator's gut and evacuation times are critical for interpreting locations of radio-tagged fish and their predators. Our objective was to determine what factors influenced the evacuation time of transmitters (0.3 g), implanted in juvenile Largemouth BassMicropterus salmoidesthrough the digestive system of adult Largemouth Bass that had preyed upon those tagged juveniles. All transmitters ingested by the predators were evacuated within 84 h. A Poisson regression model showed that transit time decreased significantly with temperature and increased with prey length and predator length. The results of this study suggest that miniature radio transmitters (e.g., 0.3 g) do not accumulate in the digestive tract of predators and that after consumption, up to 3 d of behavior (i.e., movement and habitat use) by the predator, movements could falsely be attributed to the juvenile fish. Therefore, if a distinction cannot be made between predator and tagged juvenile Largemouth Bass, we recommend not including information from the final 3 d before cessation of movement when analyzing the behavior of tagged fish. Received June 9, 2014; accepted January 28, 2015 [ABSTRACT FROM PUBLISHER]

We examined seasonal dynamics of prey availability and diets of Largemouth BassMicropterus salmoidesin the St. Johns River, Florida. The four most common prey species were Threadfin ShadDorosoma petenense, Bay AnchovyAnchoa mitchilli, Atlantic CroakerMicropogonias undulatus, and Atlantic MenhadenBrevoortia tyrannus. The number of prey found in Largemouth Bass varied significantly by month (year-round) and predator size (“small,” <356 mm TL,n= 267; “medium,” 356–432 mm TL,n= 205; “large,” >432 mm TL,n= 114). Atlantic Menhaden were most energetically beneficial to predators when available. Of the four most common prey species collected in trawls, only menhaden trawl catch was positively correlated with its appearance in bass diets. Menhaden were eaten by bass of all sizes, but were found only from September through November. Largemouth Bass did not feed heavily on juvenile anadromous shadsAlosaspp. during their autumn migration, but this likely reflected low abundance of these clupeid species. The seasonal diversity of prey available in the St. Johns River may contribute to its being one of the most productive Largemouth Bass fisheries in Florida. Received June 23, 2014; accepted October 22, 2014 [ABSTRACT FROM AUTHOR]

Recent advances in the technology of miniature radio transmitters have allowed researchers to study smaller fish, including juveniles, for which behavioral information is lacking. Transmitters selected should have minimal effects on tagged fish so that inferences may be made about untagged individuals. Our objective was to evaluate the short-term effects of surgically inserted dummy transmitters (1.2–2.7% of the fish's body weight) on growth and predator avoidance in 90–120-mm hatchery-reared Largemouth BassMicropterus salmoides.We compared growth and predator avoidance between tagged and untagged (control) fish in tanks. Mortality of tagged and control fish was variable by tank and was most commonly caused by columnaris, a fish disease widespread in aquaculture. A slight impairment of growth for tagged fish (difference of as much as 1.19% body weight gained per day) was observed during experiments run for 21 and 30 d. At the conclusion of each growth experiment, most fish had shed their suture and incisions had completely healed. No incidents of transmitter expulsion occurred in either growth experiment. During the predation trials, 49% of both tagged fish and controls were eaten by predators, suggesting that the radio tags did not affect the fish's vulnerability to predation. Despite some mortality observed in the laboratory and slight growth impairment in tagged fish, predation studies implied that the ability to avoid predators was not affected in tagged individuals. Therefore, we conclude that surgical implantation of radio transmitters can be a valid tagging technique for examining the behavior of juvenile Largemouth Bass in short-term field studies. Received June 14, 2013; accepted October 7, 2013 [ABSTRACT FROM AUTHOR]

Fisheries assessments often rely on age composition data to infer information about growth, mortality, and the outcome of various management policies. To reduce the costs of estimating the age of all fish collected (i.e., via direct aging), an age–length key (ALK) is often developed by directly aging only a subsample of fish and estimating the ages of the remaining fish based on observed lengths. Although this approach is common, there is little guidance in the literature for determining the appropriate total sample size and numbers of fish needed to directly age for each length bin. We developed a stochastic simulation to evaluate the sample-size requirement for using ALKs to estimate von Bertalanffy growth parameters and the instantaneous rate of total mortality (Z). The simulations accounted for variation in life history characteristics of stocks and exploitation rates of fisheries. Our simulations suggested that for overfished populations, aging more fish per bin provides negligible benefits whereas collecting larger total sample sizes could improve bias and precision ofZestimates. These results also indicated that bias and precision was relatively uninfluenced by fish life history type, which may allow for standardization of field collection methods across a wide range of fish species. In most cases, total sample sizes of 500–1,000 and 10 fish aged per bin provided near optimal performance in accuracy and precision, suggesting that this could be a guideline for many studies. Received August 21, 2012; accepted January 14, 2013 [ABSTRACT FROM PUBLISHER]

Electrofishing CPUE data are commonly used to index temporal trends in abundance in fish monitoring programs, but the reliability of this index requires the assumption that the fraction of fish stock caught per unit effort (catchability, q) is relatively precise and constant through time. We evaluated how fish species, season, and lake affected electrofishing catchability in Florida lakes using a field study. We used the field study results to simulate how variable electrofishing q affects statistical power and type I error rate (i.e., the probability of detecting a difference when in fact no difference occurred). Model selection showed that electrofishing catchability varied by species, season, and lake, and submodels showed that catchability varied by lake for Largemouth Bass Micropterus salmoides and by season for Lake Chubsucker Erimyzon sucetta, and was constant across season and lake for Bluegill Lepomis macrochirus. Our results revealed that statistical power decreased and the type I error rate increased substantially if q varied through time as we observed for Largemouth Bass and Lake Chubsucker. Type I error rates were well above the expected value of 0.05, reaching as high as 0.7 for Largemouth Bass and 0.55 for Lake Chubsucker at high sample sizes. This resulted because increasing sample size improves the ability to detect real changes, but also increases the probability of detecting spurious changes due to variable q (i.e., type I error). Thus, variable catchability hinders our ability to use CPUE data to index trends in fish abundance, and monitoring programs should consider how q varies before relying on CPUE data to index fish abundance. [ABSTRACT FROM AUTHOR]

Trophy-size fish are a critical component of recreational Largemouth Bass Micropterus salmoides floridanus fisheries; therefore, many agencies have prioritized management actions to improve catches of large fish. Length-based harvest regulations are commonly used to increase the abundance of trophy-size fish, but the rarity of large fish in sampling programs makes it difficult to use field data to evaluate the effectiveness of those regulations. We used an age-structured simulation model parameterized for a trophy Largemouth Bass fishery to evaluate the potential for a range of size limits to increase abundance and angler catches of trophy Largemouth Bass (>610 mm TL). We compiled creel information from four Florida lakes with varying harvest regulations that were known to have high-quality trophy fisheries in order to assess the performance of the model. Model results were scaled to represent trips per trophy catch for a range of size limits. The model predicted that the average number of angler trips required to catch a trophy fish were expected to decline from 83 under a 350-mm minimum length limit (e.g., baseline model that represents the standard length limit in the peninsula of Florida) to 47 for a 600-mm minimum length limit if exploitation rates were 0.2. Maximum size limits and protective slot limits also showed potential to substantially improve trophy catches. The model results and creel estimates showed similar trends for the predicted number of angler trips required to catch a trophy fish on lakes managed for trophy Largemouth Bass in Florida. Our model could be combined with fish population data to forecast the effectiveness of regulation changes on trophy fish catches. This could provide insight into trophy fisheries, where field measurements of trophy abundance and angler catches are difficult to obtain with traditional sampling programs. [ABSTRACT FROM AUTHOR]

Gizzard shadDorosoma cepedianumhave been the target of removal efforts in eastern North American lakes due to their omnivorous feeding, which may increase nutrient cycling and contribute to high phytoplankton abundance. We used a simulation model to evaluate the efficacy of a gizzard shad removal program at the Harris Chain of Lakes (HCL), Florida, by testing the effects of the exploitation rate, gill-net mesh size, and harvest interval on the total population biomass and spawning potential ratio (SPR). The analysis accounted for compensatory density dependence of the gizzard shad population and uncertainty in life history parameters. The reductions in gizzard shad biomass and SPR were less than 50% for the two largest mesh sizes (89 and 102 mm) at realistic annual exploitation rates of 0.6–0.8. However, the use of smaller mesh sizes (51 and 64 mm) produced biomass and SPR reductions that exceeded 75% at comparable harvest rates. Current removal efforts at the HCL, which employ a minimum gill-net mesh size of 102 mm, are unlikely to reduce gizzard shad biomass substantially. However, smaller mesh sizes could result in increased bycatch of economically important black crappiesPomoxis nigromaculatus. Our study sheds light on the importance of using simulation models to forecast the effects of removal efforts on target fish species. The results of such models can be used to inform harvest practices to achieve desired outcomes. Received May 12, 2011; accepted September 12, 2011 [ABSTRACT FROM PUBLISHER]

Understanding the relationships between river discharge and recruitment of estuarine fishes is important because of hydrological alterations caused by anthropogenic water withdrawals. Varying river discharge alters salinity, turbidity, nutrient levels, and detrital concentrations, all of which affect estuarine biota. The lower Suwannee River, Florida, is one of the few remaining large-river systems in the United States that has no major impoundments. We assessed the relationship between seasonal river discharge and relative abundance, growth, and mortality of estuary-dependent age-0 fish of five species in the Suwannee River estuary. We analyzed 9 years of data (1997-2005) collected as part of a long-term, fishery-independent monitoring program. The results showed a positive relationship between relative abundance and river discharge for age-0 spotted seatrout , sand seatrout , and red drum . The pinfish was the only species for which relative abundance was negatively related to river discharge; the relative abundance of spot was not significantly related to changes in discharge. Instantaneous daily growth ( G) estimates were positively related to river discharge for all species except spotted seatrout, for which a negative correlation was found. Instantaneous daily mortality ( Z) estimates were positively correlated with river discharge for sand seatrout, pinfish, and red drum. The G : Z ratios for pinfish and early recruiting sand seatrout were negatively related to river discharge, indicating that recruitment potential declined with higher discharge. Changes in freshwater discharge affected the abundance, growth, and survival of these juvenile fishes, stressing the importance of water allocation decisions that affect estuarine fishes and the fisheries they support. [ABSTRACT FROM AUTHOR]

The golden perch Macquaria ambigua is a recreationally important freshwater sport and food fish species found throughout southeastern Australia. Stocking golden perch in impoundments has been used by fisheries managers to enhance existing wild populations for over 30 years. Despite widespread stocking, the contribution of stocked fish to golden perch populations has not been investigated. We evaluated the stocking contribution by using chemically marked golden perch fingerlings introduced into three lakes in which natural recruitment is low. We surveyed the lakes to determine the contribution of the stocked fish to the lake populations and found an overall contribution of 47 ± 9% (mean ± SE) at Reedy Lake, 55 ± 9% at Kangaroo Lake, find 90 ± 5% at Lake Charm. Our results indicate that, rather than replacing wild fish, stocked fish increased the abundance of adult fish at all three lakes. The contribution of stocked fish to each population declined with increased connectedness to the Loddon River, which served as the probable source for the wild fish population. Stocking programs can substantially augment fish populations when natural recruitment is very low. [ABSTRACT FROM AUTHOR]

We used an age-structured model to evaluate the impacts of recreational angling during spawning on populations of largemouth bass and the potential benefits of seasonal fishing closures. We simulated fisheries with average and high capture rates (i.e., fractions of the stock caught by anglers). We manipulated mortality rates to mimic the effects of various regulations, including (1) an open fishery with no closures, (2) a full fishery closure during the spawning season, (3) a catch-and-release fishery during the spawning season, and (4) a year-round catch-and-release fishery. We simulated two hypothetical populations: a high-productivity, low-latitude population and a low-productivity, high-latitude population. Spawning season closures produced the largest relative increases in adult abundance when applied to low-productivity populations and when capture rates were high (e.g., 70%) and harvest rates were relatively low (20%). This resulted because very high capture rates imply that most spawning fish will be caught by anglers and potentially lose their broods to nest predators. The existing evidence suggests that these conditions (very high capture rates combined with low harvest rates) are the exception rather than the rule across largemouth bass fisheries. Understanding capture and harvest rates is critical to the use of seasonal closures in recreational fisheries. [ABSTRACT FROM AUTHOR]

Commercial bycatch can potentially induce high fishing mortality and represents serious concerns for the sustainability of some fisheries. We evaluated the potential population-level impacts of commercial gill-net bycatch and recreational fishing mortality on black crappie Pomoxis nigromaculatus in Lake Dora, Florida. We assessed total black crappie bycatch and the mortality rates of black crappie entangled in gill nets, quantified recreational fishing effort and harvest, and estimated exploitation for the recreational and commercial (bycatch) fisheries. We used an equilibrium age-structured population model to assess potential population-level impacts of bycatch and recreational fishing mortality. Onboard observer data of commercial fishers showed that about 17,000 and 30,000 black crappie were captured in gill nets in 2005 and 2006, respectively. Cage experiments revealed that about 30% and 47% of black crappie captured in gill nets experienced mortality after 72 h in 2005 and 2006, respectively. The recreational fishery exploitation rate was estimated to be 42% based on angler tag returns in 2006, and commercial exploitation via bycatch from commercial gill nets was 15%. The population model suggested that the level of recreational fishing mortality observed in 2006 was probably sustainable but that additional commercial or recreational exploitation would create a risk of recruitment overfishing. The greatest risk for recruitment overfishing via bycatch occurs when other sources of exploitation are also high (e.g., via a recreational fishery). [ABSTRACT FROM AUTHOR]

We built a simulation model to assess the performance of catch-curve residuals as an index of year-class strength for a short-lived and a long-lived fish life history type across a range of assumed values for the variation in recruitment (CVR) and fishing mortality (CVF). The magnitude of CVR strongly influenced the utility of catch-curve residuals in assessing year-class strength. The probability, of finding a significant correlation between catch-curve residuals and true recruitment values exceeded 0.9 when CVR was greater than 0.5 for the long-lived and greater than 1.0 for the short-lived life history types. This suggests that larger recruitment values have a greater probability of being successfully "tracked" through the age structure. Conversely, the magnitude of interannual variation in fishing mortality weakly influenced the performance of catch-curve residuals. The inspection of individual catch-curve residuals relative to the known recruitment values that produced them showed considerable scatter, indicating that the utility of this metric in assessing individual year class strength is small. Sensitivity analyses showed that the performance of catch-curve residuals improved modestly with equal sampling vulnerability across ages and decreased slightly with increased fishing mortality. Our results suggest that catch-curve residuals can serve as a rudimentary measure of recruitment under ranges of recruitment and mortality variation similar to those frequently observed in field studies. [ABSTRACT FROM AUTHOR]

Latitudinal influences on growing season length and winter severity cause variation in prerecruitment life history across species distributions. We evaluated two recruitment hypotheses for a broadly distributed species, largemouth bass , at the southern extent of their natural range. We tested (1) whether early hatching provided a growth and survival advantage relative to later hatching through their first summer and (2) whether overwinter size-selective mortality strongly influenced recruitment to age 1 across Florida's latitudinal gradient. We sampled the 2003 and 2004 year-classes at six Florida lakes that spanned latitudes from 27°0′N to 30°5′N. Our results did not fully conform to our hypotheses or the results frequently reported from more northerly latitudes because largemouth bass that hatched early did not exhibit a growth and survival advantage at all lakes and we did not detect strong size-selective overwinter mortality. Early hatching at south Florida lakes resulted in slow growth for three of four lake and year combinations and early-hatched fish never exhibited a survival advantage relative to later-hatched fish, which was probably due to cool water temperatures soon after hatching. Environmental variability influenced the interactions between hatching period, growth, and survival for Florida's largemouth bass populations, which has implications for understanding fish recruitment across broad spatial scales. [ABSTRACT FROM AUTHOR]

The influence of benthic prey availability on growth of black crappies is poorly understood due to scant research on the relationships between benthic prey abundance and composition and black crappie diet. However, benthic taxa play an important role as prey items of black crappies during intermediate ontogenetic diet phases. We evaluated diet, growth, and abundance of black crappies in three large Florida lakes (Lochloosa, Marian, and Monroe), and we related diets to benthic prey availability at these lakes. Black crappies in Lake Monroe obtained the largest size at age, whereas those in Lake Marian had the smallest size at age. Black crappies in Lakes Lochloosa and Marian consistently exhibited positive selection of dipteran pupae; fish in Lake Monroe showed consistently positive selection of a higher-quality prey item (the mysid shrimp ) that was not available in Lakes Lochloosa and Marian. A similarity index indicated that benthic prey availability influenced consumption of benthic prey items by black crappies in all three lakes. Differences in prey availability (i.e., density and presence-absence) and prey selection influenced diet composition and ontogenetic diet shifts of black crappies. Diet and prey availability differences among lakes probably contributed to the variation in black crappie growth rates; the highest growth was observed at Lake Monroe, where the additional prey resource () was available. [ABSTRACT FROM AUTHOR]

Standardized protocols for sampling fish in lentic systems were recently established for the Florida Fish and Wildlife Conservation Commission. One of the main concerns of state biologists is that standard sampling methods could reduce the value and comparability of long-standing, fixed-transect historical data sets. Therefore, largemouth bass Micropterus salmoides were sampled by electrofishing in six lakes using both the historical and the new standard methods in spring 2006. Based on a two-way analysis of variance, the mean log-transformed catch per unit effort (CPUE) and proportional size structure of quality-size fish (PSSQ) and preferred-size fish (PSSP) did not differ significantly between the two sampling methods for any lake, when all samples were included. Based on bootstrapping analyses, which controlled for differences in sample sizes between the standard and historical methods, the variation associated with mean CPUE was generally higher for the standard method, whereas the variation associated with mean PSSP was generally higher for the historical method. Aside from PSSQ, the sample size required to obtain adequate levels of power and detection were met only by the standard method, for which a larger number of samples were collected. Our study suggests that the point estimates (i.e., means) from the historical methods can be used in trend analyses in concert with the new standard methods but that the standard method provides for better comparisons among water bodies. [ABSTRACT FROM AUTHOR]