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1.
The influence of environmental variables on largemouth bass Micropterus salmoides (Lacépède) populations in 22 shallow (mean depth 1.0–2.9 m) Nebraska lakes was evaluated. Largemouth bass exhibited density‐dependent size structure and growth, but not condition. Total annual mortality averaged only 30%. Deeper lakes contained low density largemouth bass populations with a high proportion of fish >380 mm, whereas larger lakes with little submerged vegetation had faster growth. The proportion of largemouth bass >380 mm and relative abundance tended to increase with emergent vegetation coverage. More stable recruitment was evident in shallower lakes with increased emergent vegetation coverage. Strong year classes were associated with cooler September air temperatures. Largemouth bass populations exhibited density‐dependent effects in lakes up to 332 ha. Lake depth, emergent vegetation and autumn air temperatures may influence largemouth bass populations more than previously suggested. 相似文献
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John S. Hargrove Mark W. Rogers Phillip T. Kacmar 《Fisheries Management and Ecology》2020,27(3):219-226
Millions of Florida bass, Micropterus floridanus Lesueur, are stocked annually into populations of largemouth bass, Micropterus salmoides Lacepède, to increase trophy fish abundance. However, little effort has related the role that resultant hybrids make to angler catches. Largemouth bass were sampled from an important recreational fishery subject to extensive Florida bass stocking to address the hypothesis that anglers capture Florida bass, largemouth bass and hybrids at rates equivalent to their overall abundance in the population. Fin clips obtained from tournament angling events (n = 348) and boat‐mounted electrofishing sampling (n = 219) were screened at 38 species‐diagnostic markers and individuals were assigned to genealogical classes using Bayesian clustering algorithms. No significant differences were identified between angler and electrofishing catches providing evidence that hybridised individuals stemming from a long‐term stocking programme may constitute an important contribution to tournament angling catch. 相似文献
3.
Effect of fishing effort on catch rate and catchability of largemouth bass in small impoundments 
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下载免费PDF全文 M. G. Wegener H. L. Schramm J. W. Neal P. D. Gerard 《Fisheries Management and Ecology》2018,25(1):66-76
Largemouth bass Micropterus salmoides (Lacepède) catch rates decline with sustained fishing effort, even without harvest. It is unclear why declines in catch rate occur, and little research has been directed at how to improve catch rate. Learning has been proposed as a reason for declining catch rate, but has never been tested on largemouth bass. If catch rate declines because fish learn to avoid lures, periods of no fishing could be a management tool for increasing catch rate. In this study, six small impoundments with established fish populations were fished for two May to October fishing seasons to evaluate the effect of fishing effort on catch rate. Closed seasons were implemented to test whether a 2‐month period of no fishing improved catch rates and to determine whether conditioning from factors other than being captured reduced catch rate. Mixed‐model analysis indicated catch rate and catchability declined throughout the fishing season. Catch rate and catchability increased after a 2‐month closure but soon declined to the lowest levels of the fishing season. These changes in catch rate and catchability support the conclusion of learned angler avoidance, but sustained catchability of fish not previously caught does not support that associative or social learning affected catchability. 相似文献
4.
Sayuj Poudyal Theeraporn Pulpipat Pei-Chi Wang Shih-Chu Chen 《Journal of fish diseases》2020,43(9):1097-1106
Francisella orientalis is a highly virulent, emerging bacterium that causes mass mortalities in tilapia. This pathogen also affects numerous other warm-water fish species, including three-line grunt, hybrid striped bass and various ornamental fish. This study sheds light on two new species of fish that are susceptible to F. orientalis. Asian seabass and largemouth bass showed variable levels of susceptibility in a bacterial challenge experiment. After intraperitoneally injected with a dose of 106 CFU/fish, a total of 64.28% and 21.42% mortalities were obtained in Asian seabass and largemouth bass, respectively. Meanwhile, Nile tilapia showed acute mortality of 100%. All fish showed typical lesions of francisellosis, including multifocal granulomas in the spleen and head kidney. Immunohistochemical analysis revealed strong positive signals inside the granulomas of all fish. The bacterial recovery in solid media from infected fish was highest in Nile tilapia (85.71%), followed by Asian seabass (35.71%) and largemouth bass (21.42%). PCR results tested 100% positive for Nile tilapia, and 78.57% and 21.42% for Asian seabass and largemouth bass, respectively. In conclusion, Asian seabass and largemouth bass are susceptible to this pathogen, which warrants new management strategies when employing predation polyculture systems of these species with tilapia. 相似文献
5.
Thomas M. Detmer Kyle J. Broadway Joseph J. Parkos Matthew J. Diana David H. Wahl 《Fisheries Management and Ecology》2020,27(5):540-543
Tournament 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. 相似文献
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Abstract Standardised fishing methods using gillnets (EN 14575), electric fishing (EN 14011) and hydroacoustics (WI 00230244 CEN enquiry) to estimate species composition, abundance, biomass and size distribution were compared in 14 alpine lakes >50 ha. More fish species were detected using benthic gillnets (mean = 72.7%) than electric fishing (mean = 59.5%) and pelagic gillnets (mean = 29.6%). For all but two lakes, additional information from a local fisheries manager was required to obtain a complete list of species. Biomass data generated by standardised gillnetting and hydroacoustic surveys were not fully comparable, but a positive correlation was found. Gill netting and hydroacoustics both indicated a nearly fishless habitat below 75 m, which confirmed the maximum required fishing depth according to the European Standard EN 14757. Size distributions obtained from gillnet and hydroacoustic surveys differed statistically for large fish (>40 cm). Each standardised method reflected typical shortcomings. The European standard (EN 14757) should be amended for pelagic fish habitat in deep alpine lakes to include sampling effort corresponding to water volume, and additional gillnets with larger mesh sizes (e.g. 70 mm). Furthermore, the electric fishing standard (EN 14011) should be extended to incorporate requirements of lake fish sampling. 相似文献
7.
Tian Zhao Gaël Grenouillet Thomas Pool Loïc Tudesque Julien Cucherousset 《Ecology of Freshwater Fish》2016,25(3):412-421
Gravel pit lakes are increasingly common, and there is an urgent need to better understand the functioning of these artificial and disconnected ecosystems. However, our knowledge of the environmental determinants of fish community structure within these types of lakes remains poor. In this study, we quantified the taxonomic diversity, fish species and life‐stage composition in 17 gravel pit lakes sampled in 2012 and 2013 located in south‐west France to determine the potential role of environmental variables (i.e. lake morphology, productivity, water quality and human‐use intensity) as drivers of fish community structure and composition. Our results demonstrated that fish community structure significantly differed between gravel pit lakes, and we notably found that lakes managed for angling hosted higher levels of taxonomic diversity. We also found that young and large lakes supported higher native species biomass and were dominated by native European perch (Perca fluviatilis). Older, smaller and more productive lakes, located closer to the main urban area, supported a higher biomass of non‐native species such as largemouth bass (Micropterus salmoides). Native and non‐native sport fishing species such as northern pike (Esox lucius), pikeperch (Sander lucioperca), common carp (Cyprinus carpio) and cyprinid prey species were positively associated with fishery management effort, suggesting that management practices play also a critical role in shaping fish species composition. Overall, our study demonstrated that fish community composition followed a predictable shift along environmental gradients associated with the maturation of gravel pit lakes and the associated human practices. 相似文献
8.
J. W. Gaeta M. J. Guarascio G. G. Sass S. R. Carpenter 《Ecology of Freshwater Fish》2011,20(1):92-101
Gaeta JW, Guarascio MJ, Sass GG, Carpenter SR. Lakeshore residential development and growth of largemouth bass (Micropterus salmoides): a cross‐lakes comparison.Ecology of Freshwater Fish 2011: 20: 92–101. © 2010 John Wiley & Sons A/S Abstract – Lakeshore residential development is associated with changes in littoral habitat, riparian habitat, and ecosystem function with potential impacts ramifying through aquatic food webs. Effects of these changes on economically important game fishes may vary with fish size. We investigated largemouth bass (Micropterus salmoides) size‐specific growth rates across 16 lakes spanning the range of lakeshore residential development in Wisconsin’s Northern Highland Lake District using a longitudinal multilevel model. Growth rates of small fish had a strong positive relationship with lakeshore residential development. The strength of the relationship decreased with length and became increasingly negative for fish longer than 210 mm. This pattern may be driven by a release from density‐dependent growth, shifts in available prey sources, reduced macrophyte cover, or angling‐induced selection pressures. Regardless of the mechanism, our results indicate, relative to undeveloped lakes, largemouth bass in highly developed lakes take 1.5 growing seasons longer to enter the fishery (356 mm). 相似文献
9.
Summer stratification often leads to large areas of hypolimnetic hypoxia in lakes and reservoirs. These areas of hypoxia alter fish behaviours and distributions as well as restrict access to valuable prey resources, yet few studies have examined foraging behaviour of fish in response to low dissolved oxygen (DO) concentrations. We observed foraging behaviour of juvenile largemouth bass, Micropterus salmoides, in response to varying DO concentrations in tanks that simulated a stratified lake water column during the summer: 28°C oxygenated epilimnion, 15°C deoxygenated hypolimnion. Compared with saturated concentrations (8.0–9.0 mg/L), hypolimnetic oxygen concentrations of 3.0 mg/L and 1.5 mg/L resulted in a drastic decrease in prey consumption, handling efficiency and time spent below the thermocline mainly due to avoidance behaviour of hypoxic conditions. However, we found at high hypolimnetic prey densities, individual fish were more willing to venture into reduced oxygen concentrations. Several unique behaviours including transporting prey above the oxycline for consumption, aquatic surface respiration and gill flaring were employed by largemouth bass foraging in low oxygen environments. Reduced hypolimnetic oxygen concentrations may influence and alter feeding strategies, especially for fish that rely on benthic prey resources. 相似文献
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为掌握影响我国沿海刺网渔船网具遗失率(R_G)的因子及其程度,对中国沿海渔民开展了问卷调查。利用调查数据,结合GAM模型分析了影响我国刺网渔船网具遗失率的因子及其程度。结果显示:(1)影响我国沿海刺网渔船网具遗失率的因子(解释偏差)分别为单航次天数(86.8%)、年作业天数(4.2%)、单航次渔具携带重量(2.8%)、作业水深(2.4%)、渔船吨位(0.9%)和年均渔具采购数量(0.1%);(2)GAM模型能用于研究渔船网具遗失率和影响因子之间的关系;(3)随着单航次天数和年作业天数的增加,R_G呈上升的趋势;(4)随着作业水深的增加、单航次渔具携带重量超过18 000 kg时,R_G呈下降趋势。建议采取以下措施以降低刺网渔船网具遗失率:(1)单航次天数不得超过30 d,减少年作业天数;(2)根据渔船的吨位,确保网具单航次携带重量在18 000 kg以上;(3)根据刺网渔具的高度规定作业水深和作业渔区;(4)渔船总吨位控制在200 t以内。 相似文献
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C. D. SUSKI S. J. COOKE S. S. KILLEN† D. H. WAHL D. P. PHILIPP & B. L. TUFTS 《Fisheries Management and Ecology》2005,12(1):19-26
Abstract During live-release angling tournaments in North America, fish are typically retained in livewells onboard boats during the angling day. Mortality of fish occurs at some tournaments, and wave intensities and livewell conditions may influence mortality levels. This study used two species of fish targeted in live-release angling tournaments in North America (largemouth bass Micropterus salmoides L. and walleye Sander vitreus L.) to quantify the response(s) of fish in livewells to different wave treatments. Video analyses revealed that largemouth bass were active during low intensity disturbances, but during violent boat movements tended to settle to the bottom of the livewell and orient to face the direction of the disturbance. Walleye were less active than bass for all treatments, and additionally did not orient to face the direction of disturbance, consequently contacting the side of the livewell during boat rocking. These results are considered in the context of mortality at live-release tournaments. 相似文献
12.
Outbreaks of ulcerative disease associated with ranavirus infection in barcoo grunter,Scortum barcoo (McCulloch & Waite) 下载免费PDF全文
下载免费PDF全文 P Kayansamruaj A Rangsichol H T Dong C Rodkhum M Maita T Katagiri N Pirarat 《Journal of fish diseases》2017,40(10):1341-1350
In 2013, an outbreak of ulcerative disease associated with ranavirus infection occurred in barcoo grunter, Scortum barcoo (McCulloch & Waite), farms in Thailand. Affected fish exhibited extensive haemorrhage and ulceration on skin and muscle. Microscopically, the widespread haemorrhagic ulceration and necrosis were noted in gill, spleen and kidney with the presence of intracytoplasmic eosinophilic inclusion bodies. When healthy barcoo grunter were experimentally challenged via intraperitoneal and oral modes with homogenized tissue of naturally infected fish, gross and microscopic lesions occurred with a cumulative mortality of 70–90%. Both naturally and experimentally infected fish yielded positive results to the ranavirus‐specific PCR. The full‐length nucleotide sequences of major capsid protein gene of ranaviral isolates were similar to largemouth bass virus (LMBV) and identical to largemouth bass ulcerative syndrome virus (LBUSV), previously reported in farmed largemouth bass (Micropterus salmoides L.), which also produced lethal ulcerative skin lesions. To the best of our knowledge, this is the first report of a LMBV‐like infection associated with skin lesions in barcoo grunter, adding to the known examples of ranavirus infection associated with skin ulceration in fish. 相似文献
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M. J. Millard S. A. Welsh J. W. Fletcher J. Mohler A. Kahnle & K. Hattala 《Fisheries Management and Ecology》2003,10(5):295-300
Catch‐and‐release fishing has increased in many fisheries, but its contribution to fishing mortality is rarely estimated. This study estimated catch and release mortality rates of striped bass, Morone saxatilis (Walbaum), for the spring recreational fishery in the Hudson River. Treatment fish (caught with live bait on spinning gear) and control fish (captured by electric fishing) were placed in in situ holding pens for 5 days. Mortality rates were estimated using conditional instantaneous mortality rates and additive finite mortality rates. Influences of variables (playing and handling time, hook location, degree of bleeding and fish length) on hooking mortality rates were examined by logistic regression. Conditional instantaneous mortality rates and additive finite mortality rates were 31 and 28%, respectively. Hook location significantly affected the survival of striped bass. Angling catch, effort, and release rates must be integrated with associated hooking mortality rates before this component of overall population mortality can be incorporated into management decisions. 相似文献
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Variation in individual size has important consequences for a number of characteristics of fish, which can impact fish populations.
The impact of fish size on recovery following exercise, however, is poorly understood, with little information existing on
the recovery of ionic/osmotic variables. The goal of this study was to quantify not only how allometry impacts the magnitude
of physiological disturbance following burst exercise in largemouth bass (Micropterus salmoides), but also how allometry impacts the time required for exercise-induced disturbances to return to baseline levels. To accomplish
this goal, two size classes of largemouth bass (large = 772–1,441 g total weight, mean = 1,125 g; small = 93–238 g, mean = 148 g)
were exercised for 60 s and allowed to recover for 0, 1, 2, or 4 h before being sampled for plasma and white muscle. Large
largemouth bass exhibited elevated concentrations of plasma glucose and sodium relative to small fish following a common exercise
challenge. Large fish required additional time to clear metabolic disturbances in plasma and failed to restore potassium to
basal levels even following 4 h of recovery, indicating an improved ability of the smaller fish to recover from disturbances.
Results are further discussed in the context of physiological ecology and fitness for largemouth bass. 相似文献
17.
The success and value of yellow perch, Perca flavescens (Mitchill), stocking programmes are largely unknown because of the difficulties in differentiating between naturally recruited and translocated stocks. To determine stocking contributions of yellow perch, fingerlings and adults were collected from natural rearing ponds in south-eastern South Dakota. Prior to stocking, all fish were marked for 6 h in transfer tanks containing 700 mg L−1 oxytetracycline hydrochloride. Six lakes containing yellow perch populations were supplemented at low, medium and high stocking densities of about 25, 135 or 200 fish ha−1 , respectively. Yellow perch populations were subsequently sampled with experimental gill nets during late summer; two lakes were resampled with additional gears (electric fishing, trap nets and cloverleaf traps). Yellow perch were processed for routine measurements, and saggital otoliths were removed to determine the origin of the fish. Stock contribution estimates determined from gill-net samples for Island (low), Oak (low), Twin (medium) and Wall (high) lakes were approximately 18, 5, 41, and 38%, respectively. Samples from other gears provided stock contributions of 15 and 10% for Cavour Lake and 41% for Diamond Lake (high density stockings). Although these results showed that supplemental stockings were successful, variability in stock contributions among populations indicates a need for further assessment of variables that may influence the stocking success of yellow perch. 相似文献
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Abstract – Common carp Cyprinus carpio is a widespread invasive species that, in high abundance, can impose numerous deleterious effects in aquatic ecosystems. Common carp increase turbidity and nutrient availability while reducing invertebrate prey resources and aquatic macrophytes, transforming shallow lakes from the clear‐ to turbid‐water state. However, potential effects of common carp on native fish communities have received limited attention. We evaluated the relationships among relative abundances of nine native fishes and common carp for 81 lakes in eastern South Dakota and their associated physicochemical characteristics. Inverse threshold relationships among relative abundances of native fishes and common carp were identified for black bullhead Ameiurus melas, black crappie Pomoxis nigromaculatus, bluegill Lepomis macrochirus, white bass Morone chrysops and northern pike Esox lucius, while marginally significant relationships were detected for largemouth bass Micropterus salmoides and smallmouth bass M. dolomieu. Lakes where common carp relative abundance exceeded 0.6 fish per net night had low abundance of native fishes, whereas lower abundance of common carp resulted in variable abundance of native fishes. Lakes with abundance of common carp surpassing 0.6 fish per net night were also characterised by larger surface areas and watersheds and impaired water quality (higher dissolved solids and chlorophyll a concentrations and lower secchi depth). Our results are consistent with the biotic‐abiotic constraining hypothesis that proposes biotic factors can regulate fish populations regardless of abiotic conditions. Thus, common carp abundance may need to be reduced and sustained below ecological thresholds to improve water quality and increase abundance of native fishes. 相似文献
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