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1.
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   

2.
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   

3.
Catch‐and‐release angling is popular in many parts of the world and plays an increasingly important role in management of recreational fisheries. Although the magnitude of catch‐and‐release mortality is well documented for many species, potential sublethal effects have been little studied. An experiment was conducted to assess directly the effects of catch‐and‐release angling on growth of largemouth bass, Micropterus salmoides Lacépède. Angling mortality was 0.00 ± 0.092% for largemouth bass caught on plastic grubs. There was no difference (P = 0.57) in weight gain between caught and uncaught fish over a 40‐day angling and recovery period. Although catch‐and‐release angling appears to have no effect on largemouth bass growth, previous studies documented sublethal effects on growth and reproduction in other species, suggesting that the occurrence and magnitude of sublethal effects vary among species.  相似文献   

4.
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   

5.
Abstract  Harvest regulations in stream fisheries are used to improve fisheries and protect vulnerable fish stocks, but objectives are often not fulfilled. Roving interviews of grayling, Thymallus thymallus L., and brown trout, Salmo trutta L., anglers in north Swedish streams were performed during a 15-year-period to reveal the effects of regulation changes and levels of compliance. Harvest of fish below minimum size limits declined with time in river sections with 25- and 30-cm minimum size limits. No clear time trend was found for the 35-cm size limit. In addition, the proportion of voluntary released legal-sized fish increased over time, indicating a change in angler attitudes. The overall effect of increasing the minimum size limit was lowering of angler-induced fishing mortality. Interview data revealed perception, shared by many anglers, of an acceptable fish size to take home for food. From a management perspective, the realised effect of angler behaviour on the fish populations needs to be considered.  相似文献   

6.
Abstract– Lake Ashbaugh, located in northeast Arkansas, was constructed in 1981, and initially stocked with Florida largemouth bass followed by supplemental stockings of northern largemouth bass. Allele frequencies of three discriminant allozyme loci (sAAT-B, sIDH-B, sMDH-B) between Florida and northern largemouth bass were determined for 414 largemouth bass collected between 1994 and 1996. Fx bass dominated our sample, with 62.3% possessing Florida largemouth bass alleles. A high incidence of Hardy-Weinberg disequilibrium was observed, indicative of genetic change within the population. No significant differences were identified for frequency of age classes, relative weight, and length at age between the northern, F1 and Fx phenotypes. Despite being located north of what is generally considered suitable for stocking Florida largemouth bass, it was demonstrated that temperature is not selective at present against bass possessing Florida largemouth bass alleles. However, caution should prevail when introducing non-native stock into native gene complexes, as introduced genes persist through many generations.  相似文献   

7.
Three lakes were repeatedly sampled at night using boat electric fishing, experimental gill netting, and fyke netting from May to November 1993 to evaluate the feasibility of using proportional stock density (PSD) to monitor warm-water fish populations in Washington State, USA. Additionally, average night-time boat electric fishing catch-per-effort of largemouth bass, Micropterus salmoides (Lacepéde), from 30 Washington lakes was also analysed to determine the amount of effort required to obtain adequate samples for precise PSD estimates. Temporal variations in PSD were not large enough to affect the management of warm-water fish populations in the small Washington lakes studied. However, the considerable effort required to obtain precise PSD estimates may limit its usefulness for warm-water fisheries surveys in the Pacific Northwest. On average, from three to 13 nights of electric fishing effort are needed to capture enough stock-length largemouth bass for PSD estimates, depending on the precision desired (80–95%) and the location of the lake (eastern or western Washington). Catch of stock-length fish can be maximized by using electric fishing for centrarchids and gill netting for yellow perch, Perca flavescens (Mitchill), in June or September. Adequate samples for precise PSD estimates can be difficult to obtain from Pacific Northwestern lakes, even when using recommended gear at optimum sampling times. Inability to capture an adequate sample size for precise PSD estimates may be responsible for some of the fluctuation in PSDs in some studies of warm-water fish populations in northern areas. Managers in other northern climates may find that low sample size may account for large variations in PSDs reported.  相似文献   

8.
Abstract  This paper summarises recent peer-reviewed literature addressing the effects of catch-and-release angling on black bass, Micropterus spp., to facilitate management and conservation of these fish. Traditionally, the effects of catch and release have been evaluated by measuring mortality. Many recent studies have measured sublethal effects on physiology and behaviour. There is also greater emphasis on adding more realism to sublethal catch-and-release experiments through angler involvement in research activities and by conducting studies in the field rather than in laboratory environments. Owing to these advances, there have been a number of recent findings, which are summarised here, related to air exposure, gear (e.g. circle hooks) and the weigh-in procedure that are particularly relevant to black bass anglers, tournament organisers and fishery managers. Additional research is particularly needed for: (1) population-level effects of angling for nesting fish; (2) population-level effects of tournament-associated mortality; (3) effectiveness of livewell additives for enhancing survival; (4) consequences of fish displacement in competitive events; (5) effects of weigh-in procedures and other organisational issues on fish condition and survival; and (6) reducing barotrauma.  相似文献   

9.
Abstract  Recreational shore angling in the Atlantic Ocean between Moledo and Aveiro (Portugal) was examined using roving creel surveys (March/September 2001). Cooperation was high (90% of 2310 anglers approached). At least 39 species of fish were caught at a rate of approximately 0.5 fish angler h−1. An estimated 7319 kg of Dicentrarchus labrax (L.), with 45.6% below the minimum legal size, and 2040 kg of sea breams (genus Diplodus ), correspond to 5.75% and 1.19% of the commercial landings in the same geographical area, respectively. The results shed light on a number of issues relevant to integrated coastal management, including temporal and spatial distribution of fishing effort, species caught, sizes of fish, catch rates, and factors influencing catches and angler satisfaction. Whilst the results suggest that the catches of sea breams and sea bass by day-time recreational shore angling in northern Portugal are small compared with commercial fishing, other recreational activities, such as boat fishing and spear-fishing, must be assessed.  相似文献   

10.
A 74‐day experiment was conducted to evaluate the production performance and water quality variation in three types of farming system for largemouth bass Micropterus salmoides. The tested aquaculture models included monoculture of largemouth bass (MC), polyculture of largemouth bass, gibel carp Carassius auratus gibelio and silver carp Hypophthalmichthys molitrix (PC), and integrated culture of largemouth bass, gibel carp, silver carp and freshwater pearl mussel Hyriopsis cumingii (IC). The ratio of largemouth bass, gibel carp and silver carp was 30:2:1 in the PC model, and the ratio of largemouth bass, gibel carp, silver carp and mussel was 30:2:1:5 in the IC model. The largemouth bass were fed with formulated feed twice daily. No significant differences were found in weight gain and yield of largemouth bass, total fish yield, nitrogen (N) and phosphorus (P) utilization efficiencies, N and P wastes, pH, nitrite, nitrate, reactive phosphate, total nitrogen, total phosphorus, total organic carbon, chemical oxygen demand, 5‐day biochemical oxygen demand, chlorophyll a, primary productivity among the MC, PC and IC models. The ammonia was lower, while the dissolved oxygen was higher in the PC tanks than in the MC tanks. These results suggest that the environment situation was better in the PC tanks relative to that in the MC tanks. The present study reveals that the PC model should be a way to optimize the aquaculture model for commercial largemouth bass farming.  相似文献   

11.
Back Bay is an oligohaline, coastal bay in southeast Virginia, USA. Since 2004, leeches have been observed in the oral cavities of largemouth bass (Micropterus salmoides) in this body of water. Leeches (Myzobdella lugubris) have previously been documented in the oral cavities of largemouth bass in the Currituck Sound, which is confluent with Back Bay on its southern border. Supplemental stocking of largemouth bass in Back Bay since 2009 has resulted in an increasing population; however, concern exists that leech infestation may be negatively affecting health of larger fish, which are still less abundant than expected. Despite the wide distribution of this leech, there is little available literature regarding its health impacts on hosts. In this study, we examine potential impacts of oral leech infestations on stress markers and haematological parameters of largemouth bass in Back Bay. No significant changes in plasma glucose or cortisol were observed between leech‐infested and uninfested fish, and haematological parameters were not significantly different between the groups. Further, there was no evidence of systemic infections associated with leech infestation.  相似文献   

12.
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   

13.
Abstract  This study evaluated how different angling practices affect the short-term post-release behaviour of nest-guarding male black bass, Micropterus spp. Male largemouth bass, M. salmoides (Lacepède), and smallmouth bass, M. dolomieu (Lacepède), were angled from their nests and subjected to treatments designed to simulate a variety of common angling practices associated with catch-and-release angling, including fishing tournaments. In addition, some nests had broods reduced (removal of the majority of the eggs or fry from the nest) during the angling treatments to simulate predation of offspring during the angling event. Fish subjected to procedures simulating fishing tournaments (including a 1-h livewell confinement and release 100 m from the nest) exhibited significantly longer rest periods prior to returning to their nest than did other treatment groups. This rest period was longer for largemouth bass than smallmouth bass. Brood removal and air exposure increased abandonment rates compared with controls. These results show that sublethal stressors inherent in some angling practices (such as air exposure and livewell confinement) may delay the return of male black bass to their nest. In the presence of nest predators, the delay in return time could result in increased nest abandonment.  相似文献   

14.
Color vision, accommodation and visual acuity in the largemouth bass   总被引：1，自引：1，他引：1  
The largemouth bass is a sight feeder and one of the most popular freshwater fish for lure fishing. While lures a have variety of colors and forms, there is no information on the color vision and form perception in the largemouth bass. We recorded S-potentials from the isolate retinae of the largemouth bass to examine color vision electrophysiologically. The occurrence of the C-response provided direct evidence for the possession of color vision. L-responses recorded indicated a high spectral sensitivity to red. The direction and distance of lens movement of a specimen of 43 cm in fork length indicated a horizontal visual axis and the near point at 13.5 cm, respectively. The visual acuity calculated from the cone density and the focal distance of the lens was 0.10. Histological characteristics of the retina indicated that the eyes are well adapted to both form and movement perceptions.  相似文献   

15.
Fish are increasingly exposed to anthropogenic stressors from human developments and activities such as agriculture, urbanization, pollution and fishing. Lethal impacts of these stressors have been studied but the potential sublethal impacts, such as behavioural changes or reduced growth and reproduction, have often been overlooked. Unlike mortality, sublethal impacts are broad and difficult to quantify experimentally. As a result, sublethal impacts are often ignored in regulatory frameworks and management decisions. Building on established fish bioenergetic models, we present a general method for using the population consequences of disturbance framework to investigate how stressors influence ecologically relevant life processes of fish. We partition impact into the initial energetic cost of attempts to escape from the stressor, followed by the energetic impacts of any injury or behavioural change, and their consequent effects on life processes. As a case study, we assess the sublethal effects of catch and release angling for the European sea bass (Dicentrachus labrax, Moronidae), a popular target species for recreational fishers. The energy budget model described is not intended to replace existing experimental approaches but does provide a simple way to account for sublethal impacts in assessment of the impact of recreational fisheries and aid development of robust management approaches. There is potential to apply our energy budget approach to investigate a broad range of stressors and cumulative impacts for many fish species while also using individual‐based models to estimate population‐level impacts.  相似文献   

16.
Fish rhabdoviruses are a family of viruses responsible for large‐scale fish die‐offs worldwide. Here, we reported the isolation and identification of a member of rhabdoviruses from wild largemouth bass (Micropterus salmoides) in the coastal area of the Pearl River Estuary, China. This virus isolate was identified as viral haemorrhagic septicaemia virus (VHSV) by specific RT‐PCR. Furthermore, the virus (VHSVLB2018) was isolated by cell culture using fathead minnow cells and confirmed by RT‐PCR. Electron microscopy showed the presence of bullet‐shaped viral particles in the cytoplasm of infected cells. The complete sequencing of VHSVLB2018 confirmed that it was genome configuration typical of rhabdoviruses. Phylogenetic analysis based on whole‐genome sequences and G gene nucleotides sequences revealed that VHSVLB2018 was assigned to VHSV genogroup Ⅳa. The pathogenicity of VHSVLB2018 was determined in infection experiments using specific pathogen‐free largemouth bass juveniles. VHSVLB2018‐infected fish showed typical clinical signs of VHSV disease, including darkened skin, petechial haemorrhages and pale enlarged livers, with the cumulative mortalities reached 63.3%–93.3% by 7 days post‐infection. VHSVLB2018 was re‐isolated from dead fish and confirmed by RT‐PCR. Together, this is the first report of isolation and identification of a VHSV isolate from wild largemouth bass in China.  相似文献   

17.
Abstract  Removal of piscivores may affect population size structure, abundance and growth rates of the remaining fish community. A total of 572 northern pike, Esox lucius L., was removed from 25-ha West Long Lake, Nebraska from 2003 to 2006. The northern pike population was reduced from 36 fish ha−1 and 22 kg ha−1 in 2002 to 20 fish ha−1 and 9 kg ha−1 in 2006. The northern pike population shifted to dominance by smaller individuals. Relative abundance increased for bluegill, Lepomis macrochirus Rafinesque, but remained similar between years for largemouth bass, Micropterus salmoides (Lacepède), and yellow perch, Perca flavescens (Mitchill). Bluegill and yellow perch size structure increased probably because of reduced predation by northern pike. The effects of reduced northern pike density on largemouth bass were less evident. The largemouth bass population may be returning to higher density with smaller size structure observed before pike were introduced. The sport fish community responded positively to the removal of northern pike in this small lake.  相似文献   

18.
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   

19.
Angler satisfaction is based on the presence of catchable fish, and therefore, understanding the mechanisms driving catchability is important for fisheries biologists and managers. Lure avoidance learning (including via social learning) may be a driver of catchability, but these mechanisms have not been explored in depth. To address this, largemouth bass, Micropterus salmoides (Lacépède), were stocked into four ponds, and two were angled using a green plastic worm. Naïve bass were then introduced into all ponds, and angling commenced using a sequence of three lures (green plastic worm, white plastic worm and in‐line spinnerbait). Naive bass stocked alongside experienced conspecifics were not less catchable, indicating socially learned lure avoidance did not take place. Catch rates declined across sessions until the switch to the spinnerbait, when rates temporarily spiked. This suggests that the similarity of a novel lure to previously experienced lures may determine if a fish avoids angling capture.  相似文献   

20.
Largemouth bass virus (LMBV) is a recently discovered iridovirus that causes a fatal disease of largemouth bass, Micropterus salmoides (Lacepède). Fish can become infected by waterborne LMBV, but oral transmission of this virus has not been demonstrated previously. Largemouth bass were gavaged with guppies, Poecilia reticulata Peters, which had been injected with LMBV, and then sampled periodically during a 7‐week observation period. The dose of LMBV averaged 105.6 tissue culture infectious doses – 50% cytopathic endpoint (TCID50) per largemouth bass. Five of 24 largemouth bass exposed to LMBV became infected with the virus, but none of the fish had clinical signs typical of LMBV disease. Virus titres in largemouth bass were highest in swim bladder (105.5–9.5 TCID50 g?1) and were 105.2 TCID50 g?1 or lower in cutaneous mucus, head kidney, trunk kidney, spleen, gonad and intestine. These results indicate that LMBV can be transmitted orally to largemouth bass, but further study is needed to determine the factors affecting pathogenicity of the virus.  相似文献   

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