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1.
Largemouth bass Micropterus salmoides (Lacepède) use of installed habitat structure was evaluated in a large Midwestern USA reservoir to determine whether or not these structures were used in similar proportion to natural habitats. Seventy largemouth bass (>380 mm total length) were surgically implanted with radio transmitters and a subset was relocated monthly during day and night for one year. The top habitat selection models (based on Akaike's information criterion) suggest largemouth bass select 2–4 m depths during night and 4–7 m during day, whereas littoral structure selection was similar across diel periods. Largemouth bass selected boat docks at twice the rate of other structures. Installed woody structure was selected at similar rates to naturally occurring complex woody structure, whereas both were selected at a higher rate than simple woody structure. The results suggest the addition of woody structure may concentrate largemouth bass and mitigate the loss of woody habitat in a large reservoir.  相似文献   

2.
Activity patterns of largemouth bass in a subtropical US reservoir   总被引：1，自引：0，他引：1  
Abstract  Nine largemouth bass, Micropterus salmoides Lacepède, >1.5 kg were implanted with radio tags and tracked for 1 year in an embayment of Lake Seminole, Georgia, USA. Most largemouth bass movement was <50 m h−1 in all seasons and at all times of day. During the day largemouth bass were offshore in deeper water near large woody structures and moved little. Movement was lower during dusk and night periods, and a general movement towards shoreline areas was evident. Water depths where largemouth bass were located had bimodal distributions in all seasons and diel periods, with one mode typically at depths <1 m and another around 3 m. Home ranges were typically largest in the summer and smallest in the winter. Largemouth bass appeared to divide their time between an offshore resting area, primarily occupied during the day, and a near-shore area, where foraging presumably occurred, primarily used during low-light periods. The largemouth bass population in Lake Seminole consists of multiple overlapping subpopulations, offering the opportunity for embayment-specific management.  相似文献   

3.
Abstract— We studied the trophic interactions and spatial distributions of bluegills Lepomis macrochirus and largemouth bass Micropterus salmoides in a macrophyte bed in Lake Onalaska, a backwater lake in the upper Mississippi River. The diets of adult and age-0 bluegills were similar and changed seasonally probably in response to changes in life stages of macroinvertebrates (i. e. emergence of winged adults). Diets and diel patterns of abundance of bluegill suggest that age-O and adults were feeding in the vegetated, littoral zone. Predation by age-O largemouth bass appears to influence use of vegetated habitat by age-0 bluegills. In summer, when most age-O bluegills were vulnerable to predation by age-O largemouth bass, bluegill abundance was strongly correlated with vegetation biomass. In October and November, piscivory by age-O largemouth bass was limited by gape. Consequently, the relationship between the abundance of age-O bluegills and vegetation biomass was weakened because predation risk by age-O largemouth bass was reduced.  相似文献   

4.
Abstract. Fifty each of F2-generation gold ( gg ), bronze ( Gg ), and black ( GG ) Oreochromis mossambicus (Peters) and either zero, four or eight largemouth bass, Micropterus salmoides , (Lacepède) were stocked in 20-m2 concrete tanks. After 7 days, water in all tanks was drained, and fish in each tank were censused. Largemouth bass ate 18% of the tilapia in the four-bass treatment (1 tilapia/bass/day) and 60% of the tilapia in the eight-bass treatment (1·6 tilapia/bass/day); the difference was significant (P=0–05). In the four-bass treatment there was a greater observed mean predation rate on gold than that on black or on bronze tilapia, but the difference was not significant: largemouth bass ate 25% of the gold tilapia, 16% of the bronze tilapia, and 13% of the black tilapia. In the eight-bass treatment, predation on the gold tilapia was significantly greater than that on both bronze (P=0·05) and on black (P=0·06) tilapia; predation on bronze and black tilapia was similar: largemouth bass ate 80% of the gold tilapia, 48% of the bronze tilapia, and 51% of the black tilapia. Overall average total predation (both treatments combined) on gold tilapia was significantly (P=0·06) greater than that on both bronze and on black tilapia, which did not differ: largemouth bass ate 52% of the gold tilapia, 32% of the bronze tilapia, and 32% of the black tilapia. The increased vulnerability of gold tilapia to predation was a negative pleiotropic effect of the gg genotype.  相似文献   

5.
Abstract – We assessed temporal dynamics and variation among species and age-classes in the diets of age 0 and age 1 piscivorous fish species in Spirit Lake, Iowa, USA during 1997 and 1998. Species included walleye Stizostedion vitreum , yellow perch Perca flavescens , smallmouth bass Micropterus dolomieui , largemouth bass Micropterus salmoides , black crappie Pomoxis nigromaculatus and white bass Morone chrysops. Thirty taxa were identified in diets, including 12 species of fish. We found dramatic differences in diets among species, among age-classes within species and over time. Walleye, largemouth bass, smallmouth bass and white bass were piscivorous at age 0. Black crappie began piscivory at age 1. Yellow perch also began piscivory at age 1, but fish were a very small fraction of age-1 diets. The primary temporal pattern, seen in several species and age-classes, was an increase in piscivory from spring to fall. This pattern was due to the lack of small, age-0 prey fish in spring. Although some patterns were evident, the taxonomic composition of the diets of all species was highly variable over time, making generalizations difficult. A surprising result was the absence of yellow perch in the diet of age-0 walleye, despite their abundance in Spirit Lake and prominence in diets of age-1 walleye and other age 1-piscivores. Age-0 yellow perch were consistently too large to be eaten by age-0 piscivores, which preyed primarily on invertebrates and smaller fish such as johnny darters Etheostoma nigrum and age 0 bluegill Lepomis macrochirus. This finding suggests that predator-prey interactions and resulting population dynamics may be quite different in Spirit Lake than in other systems dominated by walleye and yellow perch.  相似文献   

6.
Abstract  Catch rate (catch per hour) was examined for age-0 and age-1 yellow perch, Perca flavescens (Mitchill), captured in bottom trawls from 1991 to 2005 in western Lake Erie: (1) to examine variation of catch rate among years, seasons, diel periods and their interactions; and (2) to determine whether sampling during particular diel periods improved the management value of CPH data used in models to project abundance of age-2 yellow perch. Catch rate varied with year, season and the diel period during which sampling was conducted as well as by the interaction between year and season. Indices of abundance of age-0 and age-1 yellow perch estimated from night samples typically produced better fitting models and lower estimates of age-2 abundance than those using morning or afternoon samples, whereas indices using afternoon samples typically produced less precise and higher estimates of abundance. The diel period during which sampling is conducted will not affect observed population trends but may affect estimates of abundance of age-0 and age-1 yellow perch, which in turn affect recommended allowable harvest. A field experiment throughout western Lake Erie is recommended to examine potential benefits of night sampling to management of yellow perch.  相似文献   

7.
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   

8.
Abstract –  We assessed hatch dates and daily growth rates of age-0 smallmouth bass from two glacial lakes over a 3-year period. Hatching durations (19–27 days among years) of smallmouth bass occurred from late May until late June. Mean daily growth rate of age-0 smallmouth bass ranged from 0.56 to 1.56 mm·day−1. Correlation analysis indicated that hatch date had little effect on daily growth rates. Hatch date was significant in explaining variation in total length (TL) of age-0 smallmouth bass at time of capture in only three of six cases and hatch date never explained >50% of the variation in bass length. Daily growth rate significantly explained variation in smallmouth bass TL at time of capture in all six models, accounting for 31–86% of the variability in bass length. Our findings suggest that size structure of age-0 cohorts in some populations may be more strongly regulated by variation in individual daily growth rate than by hatch timing.  相似文献   

9.
Abstract –  Movement and habitat use of river blackfish ( Gadopsis marmoratus R.) was studied in a highly modified central Victorian stream (Birch Creek), Australia, using radio telemetry ( N  = 10) and mark–recapture ( N  = 113) between October 2001 to May 2002, and November to December 2002 respectively. Blackfish had a small home range of 10–26 m with strong affinity to a pool. However, small movements within a pool were common which resulted in relatively large cumulative movements. At a diel scale there were no significant differences in blackfish movement between day and night (Kruskal–Wallis test, P  = 0.95). Six of seven blackfish translocated 40 m upstream or downstream of their original positions returned within 48 h, suggesting strong affinity not only to a pool, but also to a small region within a pool. Blackfish utilised slow flowing (0–20 cm s−1) and deep waters (40–60 cm). Blackfish were strongly associated with the instream cover habitats of undercut banks and boulders. Significant differences were recorded in instream cover and water velocity used by blackfish between day and night (Kruskal–Wallis test, P  = <0.01). At night blackfish used open areas with high water velocities whereas during the day blackfish used complex undercut banks with low water velocities.  相似文献   

10.
为研究饲料中添加由桑叶黄酮、栗木单宁和桑叶多糖组成的复合植物提取物对大口黑鲈生长性能、血清生化指标和肝脏、肠道健康的影响,实验设计3个处理组,每组4个重复,分别投喂添加0、0.1%、0.2%复合植物提取物的等氮等脂饲料(J0、J1、J2),养殖周期为56 d。结果显示,与J0组相比,J2组大口黑鲈的末均重、增重率及特定生长率分别显著提高8.34%、11.24%和5.88%;3组大口黑鲈机体粗脂肪、水分、粗灰分、钙和总磷,肥满度、脏体比均无显著差异,粗蛋白含量随着复合植物提取物添加量的增加呈上升趋势,与J0组相比,J2组显著提高5.61%;J1和J2组肝体比显著降低9.10%～10.28%,血清白蛋白含量和白蛋白/球蛋白值显著提高8.28%～12.62%和13.56%～23.73%,J2组血清球蛋白含量显著降低9.47%,J1和J2组血清谷丙转氨酶、谷草转氨酶活性和血糖含量分别显著降低31.25%～46.88%、7.69%～12.54%和20.90%～22.40%;J1和J2组胆固醇和甘油三脂含量呈降低趋势,高密度脂蛋白胆固醇和低密度脂蛋白胆固醇呈升高趋势;J1和J2组肝脂空泡化程度显著...  相似文献   

11.
ABSTRACT:     To estimate the daily rations of Paralichthys olivaceus , Tarphops oligolepis and Favonigobius gymnauchen and to clarify diel variation in food availability to them, diel sampling was conducted over a 24-h period at a sandy beach in the Seto Inland Sea, Japan. The mean total length and body weight (BW) of P. olivaceus , T. oligolepis and F. gymnauchen were 32.6 mm (0.35 g), 23.7 mm (0.13 g) and 50.2 mm (1.03 g), respectively. The mean stomach contents index and percentages of stomachs with food were high during the day but low at night, indicating that these species are day-feeders. Paralichthys olivaceus and F. gymnauchen consumed mainly mysids and crangonids, whereas T. oligolepis fed chiefly on mysids. The estimated mean daily rations (95% confidence intervals) for P. olivaceus , T. oligolepis and F. gymnauchen made with the bootstrap method were 18.1 (9.3–31.3)%BW, 13.2 (7.9–24.3)%BW and 3.7 (1.7–7.4)%BW, respectively. Mysids were more abundant in the near-bottom layer during the day than at night, but the opposite was true for crangonids.  相似文献   

12.
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   

13.
Abstract –  A dietary analysis of largemouth bass ( Micropterus salmoides ), an exotic, piscivorous species, was conducted in large South Korean river systems (>third order streams, 31 sites). Micropterus salmoides larger than 100 mm exhibited intense piscivory on native Korean juvenile fishes, with levels of piscivory amongst the highest recorded globally, for native and introduced populations. Largemouth bass exhibited an ontogenetic shift in diet, showing a progressive increase in piscivory with size, typical of this species within its native range but unlike several studies on introduced largemouth bass in Europe and Africa. Sampling of fish communities at the same sites used for diet studies showed that native piscivores and the main food fish species of largemouth bass were significantly less abundant ( P  = 0.049 and 0.045, respectively) at sites where bass were present than at sites where no bass were recorded. Largemouth bass may pose a threat to the structure of fish assemblages in Korean river systems and further study of their population interactions and how to minimise their spread is needed.  相似文献   

14.
Juvenile largemouth bass Micropterus salmoides , trained to accept artificial diets, were stocked into six 0.04-ha ponds at stocking densities of either 6,175 or 12,350 fish/ha. Fish were fed a floating custom-formulated diet, containing 44% protein, once daily to satiation for 12 mo (May 1994–May 1995). At final harvest, the total yield of fish was significantly greater (P < 0.05) and feed conversion ratio (FCR) was significantly lower, for bass stocked at the higher density (4,598 kg/ha and 2.3, respectively) than when stocked at the lower density (2,354 kg/ha and 3.3, respectively). There was no significant difference (P > 0.05) in average weight, length, or survival of bass stocked at the two densities. Averaged over the study period, there were no significant differences (P > 0.05) in total ammonia-nitrogen (TAN), nitrite-nitrogen, or un-ionized ammonia concentrations in ponds in which bass were stocked at the two densities. These data indicate that largemouth bass of the size used in this study are amenable to pond culture at densities of at least 12,350 fish/ha and that higher stocking densities may be possible.  相似文献   

15.
Abstract –  Knowledge of the movements and diel behaviour of the European catfish ( Silurus glanis ), the largest European freshwater fish, is limited to anecdotal information. In a preliminary telemetry study of European catfish, the spring diel movement patterns of five adult catfish were examined. After intraperitoneal insertion of the acoustic tags, the positions of the fish were recorded automatically in the Flix Reservoir (River Ebro, NE Spain). A marked nocturnal mobility pattern was observed throughout the study. During daytime, the catfish were consistently located in the littoral zone and spent extended periods of the day hidden in concealed habitats. Catfish movements were in a radial pattern, with upstream and downstream excursions followed by returns to a previously occupied location. Significant individual variations in movement pattern were observed among the tagged fish and within the 24 h cycle for each fish. Mean instantaneous swimming speed was 0.17 body lengths per second (BL·s−1) at night but 0.09 BL·s−1 during the daytime.  相似文献   

16.
Abstract –  A whole-lake acoustic telemetry observatory situated in eastern Ontario was used to continuously monitor the three-dimensional position of 20 largemouth bass ( Micropterus salmoides ) over a 120-h period during the winter and a separate 120-h period during the early spring. These data were used to evaluate the frequency and stability of associations among fish to provide an understanding of seasonal aggregations and the sociobiology of largemouth bass. The temporal and spatial proximity of each fish relative to the other 19 individuals was assessed and, based on our definition of spatial/temporal proximity (i.e., two fish having an average hourly position <2 m apart), associations were shown to vary among fish, as well as diurnally, daily and seasonally. Associations during the winter were found to be more stable and involved fewer fish than associations during the spring. Of those fish that formed pair aggregations during the winter and spring study periods, male–female pairs occurred more often than male–male and female–female pairs. Our analysis also demonstrated that associations occurred primarily during daylight hours, suggesting that fish may use visual cues to form these aggregations.  相似文献   

17.
Abstract –  Ultrasonic telemetry and hydrodynamic modelling were used to study the migratory behaviour of 54 wild Atlantic salmon ( Salmo salar ) smolt captured in freshwater during their downstream migration and tracked in 2 years through a shallow estuary system. A high-density, fixed array of receivers provided detailed spatial and temporal resolution of behaviour in the second year of study. Smolt migration in the river occurred mostly at night and downstream migration was slower during the day. In the estuary, smolt moved seaward on ebbing tides and landward on flooding tides. The effect of current velocity was greater during the night than during the day. We documented for the first time that current velocity and diurnal period only accounted for approximately one-third of the variation in smolt ground speeds in the estuary, indicating that smolt movements were far less passive than previously reported. Smolt energetic status had no effect on smolt swimming behaviour or migratory performance. With an increase in salinity, smolt seaward movements during flooding tides were more frequent, and overall seaward ground velocity increased. The increase in salinity experienced by the smolt during their migration through the leading edge of saltwater intrusion thus induced a behavioural transition from a more passive, fluvial migration to a more active- and seaward-oriented migration.  相似文献   

18.
在基础饲料中用发酵桑叶分别替代0、15%、30%鱼粉,再对30%鱼粉替代水平饲料补充晶体赖氨酸和蛋氨酸,配制成4种等能等氮(CP 42%,GE 18 MJ/Kg)的实验饲料,分别表示为D_1、D2、D_3和D4,饲喂大口黑鲈(初始体质量10 g)8周,研究发酵桑叶替代鱼粉对大口黑鲈生长、脂质代谢和抗氧化能力的影响。结果显示,发酵桑叶替代30%鱼粉会显著降低大口黑鲈的终末体质量、特定生长率(SGR)、脏体比(VSI)和肝体比(HSI),补充晶体氨基酸(CAA)后会明显改善大口黑鲈的生长性能。各实验组蛋白质效率、饲料系数、摄食率、肥满度以及全鱼常规组成均无显著差异。发酵桑叶替代30%鱼粉会显著降低大口黑鲈血清总胆固醇(CHO)、甘油三酯(TG)、高密度脂蛋白胆固醇(HDL-C)和低密度脂蛋白胆固醇(LDL-C)含量,提高HDL-C/CHO和HDL-C/LDL-C比值。随发酵桑叶替代水平的增加,大口黑鲈血清低密度脂蛋白胆固醇(LDL-C)含量和丙二醛(MDA)含量显著降低,而超氧化物歧化酶(SOD)活性显著升高。研究表明,发酵桑叶替代适宜水平鱼粉不会影响大口黑鲈的生长,而替代鱼粉水平过高会显著抑制大口黑鲈的生长,但可以改善大口黑鲈的脂质代谢和机体抗氧化能力。饲料中补充晶体氨基酸可以提高桑叶的利用率,促进大口黑鲈生长。  相似文献   

19.
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   

20.
Abstract –  We used radio-telemetry to investigate the movement patterns of river blackfish [ Gadopsis marmoratus (Richardson)] in Armstrong Creek, south-eastern Australia between August and October 2005. Movements of 11 fish were monitored 2–3 times per week during daylight over 48 days and diel movements of six fish monitored hourly for three consecutive days and nights. Most river blackfish displayed little or no movement during the day and were confined to distinct positions in the stream. However, fish moved over significantly larger ranges and moved amongst mesohabitats at night, which would not have been detected using daylight tracking data only. River blackfish most often were located within pools, but they also commonly used riffle and run habitats. We also found that several fish used inundated riparian areas during a flood and two fish made rapid, large movements coinciding with the elevated flows. This study has revealed previously undocumented aspects of the movements and behaviour of river blackfish. The study has also shown the potential for different conclusions regarding the extent of movement by a species depending on the temporal scale and the timing of observations.  相似文献   

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