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Douglas B Noltie - One of the best experts on this subject based on the ideXlab platform.
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group holding impedes compensatory growth of hybrid sunfish
Aquaculture, 2000Co-Authors: Robert S Hayward, Ning Wang, Douglas B NoltieAbstract:An earlier study with a repeating no-feed/refeed schedule (D2 schedule) elicited compensatory growth (CG) in age-0 hybrid sunfish (F1: female green sunfish, Lepomis cyanellus×male bluegill L. macrochirus) held individually and fed ad libitum on feeding days. Weight gain under these conditions exceeded that of daily-fed controls. The present study sought to determine whether similar growth improvement would result when hybrid sunfish were held in groups and fed to satiation on the D2 schedule. In Experiment 1, age-0 hybrid sunfish were held in groups of 10 fish per 25-l chamber at 24°C and fed four times daily to apparent satiation on feeding days. Under this regime, fish fed according to the D2 schedule gained less weight than the controls (P<0.10). Experiment 2 was run in an effort to duplicate the results of the previous study. When age-0 fish were held individually at 24°C and fed ad libitum on feeding days, those fed on the D2 schedule gained significantly more weight (P<0.10) than the controls. These results indicate that group holding in combination with satiation feeding impedes the full expression of the CG capacity of hybrid sunfish. The major impediment under group holding may be the negative effects of social interactions on food consumption and growth efficiency.
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effect of feeding frequency on food consumption growth size variation and feeding pattern of age 0 hybrid sunfish
Aquaculture, 1998Co-Authors: Ning Wang, Robert S Hayward, Douglas B NoltieAbstract:Four treatment groups of age-0 hybrid sunfish (female green sunfish Lepomis cyanellus×male bluegill L. macrochirus) were fed to satiation at one of four frequencies (one, two, three or four meals per day) for 30 days. Fish fed three and four times daily showed the greatest consumption and growth rates; food conversion ratios did not differ among the four treatments (P>0.05). Because growth and food conversion were not enhanced when feeding was increased from three to four times daily, the optimal feeding frequency for growth was considered to be three times per day. However, the extent of inter-individual size variation (% change in CV) declined with increasing number of daily feedings (P<0.05), suggesting that more frequent feeding may produce fish of more uniform sizes. Daily feeding patterns also changed in response to feeding frequency, indicating that when fish are fed at a particular frequency, knowledge of feeding pattern is necessary so that appropriate food amounts can be supplied at each provisioning. Our results suggest that an optimal feeding frequency should be determined not only on the basis of growth and food conversion efficiency, but also according to influences of daily feeding pattern and the desire to achieve size uniformity.
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effect of feeding frequency on food consumption growth size variation and feeding pattern of age 0 hybrid sunfish
Aquaculture, 1998Co-Authors: Ning Wang, Robert S Hayward, Douglas B NoltieAbstract:Abstract Four treatment groups of age-0 hybrid sunfish (female green sunfish Lepomis cyanellus×male bluegill L. macrochirus) were fed to satiation at one of four frequencies (one, two, three or four meals per day) for 30 days. Fish fed three and four times daily showed the greatest consumption and growth rates; food conversion ratios did not differ among the four treatments (P>0.05). Because growth and food conversion were not enhanced when feeding was increased from three to four times daily, the optimal feeding frequency for growth was considered to be three times per day. However, the extent of inter-individual size variation (% change in CV) declined with increasing number of daily feedings (P
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use of compensatory growth to double hybrid sunfish growth rates
Transactions of The American Fisheries Society, 1997Co-Authors: Robert S Hayward, Douglas B Noltie, Ning WangAbstract:Abstract We studied the use of compensatory growth (CG) to grow fish larger than control fish that were fed every day without restriction. Five treatment groups of 10 juvenile hybrid sunfish (F1 hybrid of female green sunfish Lepomis cyanellus × male bluegill L. niacrochirus) received repeating cycles of no feeding and refeeding; fixed no-feed periods of either 2, 4, 6, 10, or 14 d distinguished the treatment groups. No-feed periods elicited the CG state and were immediately followed by days of ad libitum refeeding. Refeeding periods within each treatment group (D2, D4, D6, D 10, or D14) were continued until mean daily food consumption by fish no longer exceeded that of controls fed ad libitum every day (i.e., ad libitum refeeding was continued for as long as hyperphagia persisted, then another no-feed period began). Fish in two groups, D2 and D 14, consumed more food and significantly outgrew controls by 2 and 1.4 times, respectively, in 105-d experiments. Gross growth efficiency (GGE, fish weight gained...
Robert S Hayward - One of the best experts on this subject based on the ideXlab platform.
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rearing male bluegills indoors may be advantageous for producing food size sunfish
Journal of The World Aquaculture Society, 2006Co-Authors: Robert S Hayward, Hanping WangAbstract:.— An indicated demand for sunfish (Lepomis spp.) as a food fish remains untested because of continuing inability to efficiently rear these fishes to required large sizes (≥227 g; 0.5 lbs). A recent study involving parallel, indoor rearing of two sunfishes under favorable conditions showed that bluegills Lepomis macrochirus possessed markedly higher growth capacity than B × G hybrids (F1: male bluegill × female green sunfish, Lepomis cyanellus). B × G hybrids had been thought to possess superior growth capacity and so have received more attention than bluegills as a food-fish candidate in many areas of the USA. Reanalysis of data from the recent study with emphasis on gender differences revealed that the male bluegills possessed much higher growth capacity than male B × G hybrids, at least from May to March as Age 1 and then early Age 2 fish. Male bluegills reached 67% of food-market weight within the 10-mo period from a starting weight of 7 g; male B × G hybrids reached only 24% of this weight. Male bluegills’ more rapid growth versus male B × G hybrids’ apparently involved less growth energy allocation to gonad development. Female bluegills grew slower than male bluegills but also outgrew male and female B × G hybrids whose growth trajectories declined in midsummer (June) and remained largely flat through March. The previous view that B × G hybrids possess higher growth capacity than bluegills was fostered by studies in ponds where bluegill growth can be impeded by high reproduction rates and, as this study reveals, by high densities and exposure to suboptimal temperatures when their growth potential is high. Indoor rearing of male bluegills should ameliorate most pond-related growth impediments and take fuller advantage of their rapid growth capacity.
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determining sampling date interval for precise in situ estimates of cumulative food consumption by fishes
Canadian Journal of Fisheries and Aquatic Sciences, 2000Co-Authors: Gregory W Whitledge, Robert S HaywardAbstract:We tested the influence of sampling date interval (SDI) on precision of in situ estimates of cumulative food consumption by fishes. Daily rations of stream-dwelling green sunfish (Lepomis cyanellus) and impoundment-dwelling bluegill (Lepomis macrochirus) were estimated for 30 consecutive days using a low-effort procedure. Cumulative consumption by each species over the 30-day period (and 95% CIs) was estimated using Monte Carlo simulations. The effect of SDI on cumulative consumption estimates was examined by calculating cumulative consumption for SDIs of 1, 2, 3, 4, 5, 6, 7, 10, 14, and 30 days; the 1-day SDI served as a standard for evaluation of other SDIs. Cumulative consumption estimates began to fall outside the 95% CI for the 1-day SDI at SDIs of 3-4 days and did so with with increasing frequency as SDI increased. Error in estimating cumulative consumption was almost always 15% relative to the 1-day SDI standard at SDIs of 5 days or less but was as high as 26 and 39% at SDIs of 6 and 7 days, respec...
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group holding impedes compensatory growth of hybrid sunfish
Aquaculture, 2000Co-Authors: Robert S Hayward, Ning Wang, Douglas B NoltieAbstract:An earlier study with a repeating no-feed/refeed schedule (D2 schedule) elicited compensatory growth (CG) in age-0 hybrid sunfish (F1: female green sunfish, Lepomis cyanellus×male bluegill L. macrochirus) held individually and fed ad libitum on feeding days. Weight gain under these conditions exceeded that of daily-fed controls. The present study sought to determine whether similar growth improvement would result when hybrid sunfish were held in groups and fed to satiation on the D2 schedule. In Experiment 1, age-0 hybrid sunfish were held in groups of 10 fish per 25-l chamber at 24°C and fed four times daily to apparent satiation on feeding days. Under this regime, fish fed according to the D2 schedule gained less weight than the controls (P<0.10). Experiment 2 was run in an effort to duplicate the results of the previous study. When age-0 fish were held individually at 24°C and fed ad libitum on feeding days, those fed on the D2 schedule gained significantly more weight (P<0.10) than the controls. These results indicate that group holding in combination with satiation feeding impedes the full expression of the CG capacity of hybrid sunfish. The major impediment under group holding may be the negative effects of social interactions on food consumption and growth efficiency.
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effect of feeding frequency on food consumption growth size variation and feeding pattern of age 0 hybrid sunfish
Aquaculture, 1998Co-Authors: Ning Wang, Robert S Hayward, Douglas B NoltieAbstract:Four treatment groups of age-0 hybrid sunfish (female green sunfish Lepomis cyanellus×male bluegill L. macrochirus) were fed to satiation at one of four frequencies (one, two, three or four meals per day) for 30 days. Fish fed three and four times daily showed the greatest consumption and growth rates; food conversion ratios did not differ among the four treatments (P>0.05). Because growth and food conversion were not enhanced when feeding was increased from three to four times daily, the optimal feeding frequency for growth was considered to be three times per day. However, the extent of inter-individual size variation (% change in CV) declined with increasing number of daily feedings (P<0.05), suggesting that more frequent feeding may produce fish of more uniform sizes. Daily feeding patterns also changed in response to feeding frequency, indicating that when fish are fed at a particular frequency, knowledge of feeding pattern is necessary so that appropriate food amounts can be supplied at each provisioning. Our results suggest that an optimal feeding frequency should be determined not only on the basis of growth and food conversion efficiency, but also according to influences of daily feeding pattern and the desire to achieve size uniformity.
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effect of feeding frequency on food consumption growth size variation and feeding pattern of age 0 hybrid sunfish
Aquaculture, 1998Co-Authors: Ning Wang, Robert S Hayward, Douglas B NoltieAbstract:Abstract Four treatment groups of age-0 hybrid sunfish (female green sunfish Lepomis cyanellus×male bluegill L. macrochirus) were fed to satiation at one of four frequencies (one, two, three or four meals per day) for 30 days. Fish fed three and four times daily showed the greatest consumption and growth rates; food conversion ratios did not differ among the four treatments (P>0.05). Because growth and food conversion were not enhanced when feeding was increased from three to four times daily, the optimal feeding frequency for growth was considered to be three times per day. However, the extent of inter-individual size variation (% change in CV) declined with increasing number of daily feedings (P
Ning Wang - One of the best experts on this subject based on the ideXlab platform.
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group holding impedes compensatory growth of hybrid sunfish
Aquaculture, 2000Co-Authors: Robert S Hayward, Ning Wang, Douglas B NoltieAbstract:An earlier study with a repeating no-feed/refeed schedule (D2 schedule) elicited compensatory growth (CG) in age-0 hybrid sunfish (F1: female green sunfish, Lepomis cyanellus×male bluegill L. macrochirus) held individually and fed ad libitum on feeding days. Weight gain under these conditions exceeded that of daily-fed controls. The present study sought to determine whether similar growth improvement would result when hybrid sunfish were held in groups and fed to satiation on the D2 schedule. In Experiment 1, age-0 hybrid sunfish were held in groups of 10 fish per 25-l chamber at 24°C and fed four times daily to apparent satiation on feeding days. Under this regime, fish fed according to the D2 schedule gained less weight than the controls (P<0.10). Experiment 2 was run in an effort to duplicate the results of the previous study. When age-0 fish were held individually at 24°C and fed ad libitum on feeding days, those fed on the D2 schedule gained significantly more weight (P<0.10) than the controls. These results indicate that group holding in combination with satiation feeding impedes the full expression of the CG capacity of hybrid sunfish. The major impediment under group holding may be the negative effects of social interactions on food consumption and growth efficiency.
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effect of feeding frequency on food consumption growth size variation and feeding pattern of age 0 hybrid sunfish
Aquaculture, 1998Co-Authors: Ning Wang, Robert S Hayward, Douglas B NoltieAbstract:Four treatment groups of age-0 hybrid sunfish (female green sunfish Lepomis cyanellus×male bluegill L. macrochirus) were fed to satiation at one of four frequencies (one, two, three or four meals per day) for 30 days. Fish fed three and four times daily showed the greatest consumption and growth rates; food conversion ratios did not differ among the four treatments (P>0.05). Because growth and food conversion were not enhanced when feeding was increased from three to four times daily, the optimal feeding frequency for growth was considered to be three times per day. However, the extent of inter-individual size variation (% change in CV) declined with increasing number of daily feedings (P<0.05), suggesting that more frequent feeding may produce fish of more uniform sizes. Daily feeding patterns also changed in response to feeding frequency, indicating that when fish are fed at a particular frequency, knowledge of feeding pattern is necessary so that appropriate food amounts can be supplied at each provisioning. Our results suggest that an optimal feeding frequency should be determined not only on the basis of growth and food conversion efficiency, but also according to influences of daily feeding pattern and the desire to achieve size uniformity.
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effect of feeding frequency on food consumption growth size variation and feeding pattern of age 0 hybrid sunfish
Aquaculture, 1998Co-Authors: Ning Wang, Robert S Hayward, Douglas B NoltieAbstract:Abstract Four treatment groups of age-0 hybrid sunfish (female green sunfish Lepomis cyanellus×male bluegill L. macrochirus) were fed to satiation at one of four frequencies (one, two, three or four meals per day) for 30 days. Fish fed three and four times daily showed the greatest consumption and growth rates; food conversion ratios did not differ among the four treatments (P>0.05). Because growth and food conversion were not enhanced when feeding was increased from three to four times daily, the optimal feeding frequency for growth was considered to be three times per day. However, the extent of inter-individual size variation (% change in CV) declined with increasing number of daily feedings (P
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use of compensatory growth to double hybrid sunfish growth rates
Transactions of The American Fisheries Society, 1997Co-Authors: Robert S Hayward, Douglas B Noltie, Ning WangAbstract:Abstract We studied the use of compensatory growth (CG) to grow fish larger than control fish that were fed every day without restriction. Five treatment groups of 10 juvenile hybrid sunfish (F1 hybrid of female green sunfish Lepomis cyanellus × male bluegill L. niacrochirus) received repeating cycles of no feeding and refeeding; fixed no-feed periods of either 2, 4, 6, 10, or 14 d distinguished the treatment groups. No-feed periods elicited the CG state and were immediately followed by days of ad libitum refeeding. Refeeding periods within each treatment group (D2, D4, D6, D 10, or D14) were continued until mean daily food consumption by fish no longer exceeded that of controls fed ad libitum every day (i.e., ad libitum refeeding was continued for as long as hyperphagia persisted, then another no-feed period began). Fish in two groups, D2 and D 14, consumed more food and significantly outgrew controls by 2 and 1.4 times, respectively, in 105-d experiments. Gross growth efficiency (GGE, fish weight gained...
Brent B. Nickol - One of the best experts on this subject based on the ideXlab platform.
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Emigration of Leptorhynchoides thecatus (Acanthocephala) in Green Sunfish (Lepomis cyanellus)
Comparative Parasitology, 2008Co-Authors: Kristen E. Richardson, Dennis J. Richardson, Brent B. NickolAbstract:Leptorhynchoides thecatus, an acanthocephalan of centrarchid fishes, occurs in the pyloric ceca and the anterior intestine of green sunfish, Lepomis cyanellus. One wk post-laboratory infection, L. thecatus is found in the pyloric ceca and the anterior portion of the intestine of green sunfish, but by 3 wk postinfection, worms are present only in the pyloric ceca. This study investigated whether differential mortality (higher mortality in the intestine than in the ceca) or anteriad emigration is responsible for localization in the ceca. Chi-square analysis was performed on data obtained from 149 1-worm laboratory infections. No significant difference was found in the number of worms recovered during the course of the study; therefore, differential mortality as a mechanism for worm localization is unlikely. Furthermore, there was a decrease in prevalence of intestinal worms with a concurrent increase in prevalence of cecal worms. It is concluded that L. thecatus is localized in the pyloric ceca of green sunfish due to anteriad emigration. This emigration appears to be complete by day 2 post infection.
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experimental investigation of physiological factors that may influence microhabitat specificity exhibited by leptorhynchoides thecatus acanthocephala in green sunfish Lepomis cyanellus
Journal of Parasitology, 2000Co-Authors: Dennis J. Richardson, Brent B. NickolAbstract:Representatives of Leptorhynchoides thecatus (Acanthocephala) inhabit ceca of green sunfish but cannot survive in the anterior intestine. The influence of elevated cecal protein concentrations, pH, and amounts of lumenal materials on the microhabitat specificity of L. thecatus was investigated. An attempt was made to alter the distribution of worms in starved fish, in fish of which cecal pH was reduced, and in fish of which intestinal protein concentration was elevated. Protein concentration and pH showed no effect on worm distribution. Starving hosts had no effect on worm number or distribution but resulted in retardation of worm growth and development, providing a mechanism by which worms may overwinter and by which peak egg production may coincide with abundance of the amphipod intermediate host. None of the factors investigated is solely responsible for the microhabitat specificity of L. thecatus. It is suggested that helminth site specificity is characterized by long histories of adaptation to specific habitats with many physiological adaptations being facilitated synergistically. Maximization of sexual congress may exert an important selective pressure favoring this establishment of microhabitat specificity.
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physiological attributes of the pyloric caeca and anterior intestine of green sunfish Lepomis cyanellus potentially influencing microhabitat specificity of leptorhynchoides thecatus acanthocephala
Comparative Biochemistry and Physiology A-molecular & Integrative Physiology, 1999Co-Authors: Dennis J. Richardson, Brent B. NickolAbstract:Abstract Pyloric caeca are present in some species of fish and serve as a habitat for many helminth parasites. Physiological and biochemical attributes of luminal contents of the caeca and proximal intestine of green sunfish, Lepomis cyanellus, were compared to determine factors that could account for localization of Leptorhynchoides thecatus (Acanthocephala) in caeca after initial establishment in caeca and anterior portion of the intestine. Caecal protein concentrations were significantly higher. The anterior intestine exhibited significantly higher levels of proteolytic activity; however, caeca exhibited higher levels of aminopeptidase activity. The pH of caeca was significantly higher than that of the proximal portion of the intestine. Caeca contained greater total amounts of materials, and therefore contained greater total amounts of proteins, free amino acids, lipids, carbohydrates, and bile salts. A significant time–place interaction was detected regarding total free amino acids, suggesting that enzymatic activity in the caeca was responsible for increased amounts of intestinal amino acids. Physiological factors that might influence microhabitat specificity of L. thecatus include inadequate levels of intestinal protein, different levels of proteolytic activity (perhaps resulting from differences in pH), such as aminopeptidase activity, and lack of sufficient quantities of anterior intestinal nutrients to sustain worms. These results demonstrate subtle spatial and temporal complexities intrinsic to the environment of helminths inhabiting the teleost enteric system.
Grant E. Brown - One of the best experts on this subject based on the ideXlab platform.
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Are all signals the same? Ontogenetic change in the response to conspecific and heterospecific chemical alarm signals by juvenile green sunfish (Lepomis cyanellus)
Behavioral Ecology and Sociobiology, 2003Co-Authors: Justin L. Golub, Grant E. BrownAbstract:Within aquatic communities, individuals may gain survival benefits by responding to the chemical alarm signals of heterospecific prey guild members. Piscivorous individuals, however, should be selected to use such chemical signals as foraging cues. A variety of centrarchid species, such as largemouth bass (Micropterus salmoides), undergo an ontogenetic change in their response to the chemical alarm cues of heterospecific guild members, switching from antipredator to foraging responses. This ontogenetic shift should occur when potential foraging benefits outweigh any survival advantage gained from an antipredator response. To test this model, we exposed juvenile green sunfish (Lepomis cyanellus) to the skin extracts of conspecifics, a heterospecific prey guild member (finescale dace, Phoxinus neogeaus) or an allopatric heterospecific (green swordtails, Xiphophorus helleri). Juvenile sunfish exhibited a significant positive relationship between standard length and time spent moving and a significant negative relationship between length and time in a spine-erect posture, when exposed to dace skin extract, but not to either swordtail or conspecific skin extracts. Smaller individuals of less than 90 mm standard length (SL) decreased time moving and increased time with spines erect (indicating an antipredator response) while larger individuals (>90 mm SL) increased time moving and decreased time with spines erect (indicating a foraging response), when exposed to dace skin extract. Conversely, juvenile sunfish, regardless of size tested, always exhibited an antipredator response to conspecific skin extract. Sunfish exhibited no change in behaviour in response to swordtail skin extracts. These data further support our model of a threat sensitive trade-off in the response to chemical alarm signals by juvenile centrarchids.
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Chemical Alarm Signals in Juvenile Green Sunfish (Lepomis cyanellus, Centrarchidae)
Copeia, 2000Co-Authors: Grant E. Brown, Scott BrennanAbstract:We investigated the presence of chemical alarm signals in juvenile Green Sunfish (Lepomis cyanellus) under laboratory conditions. We exposed individual sunfish to skin extracts of conspecifics and swordtails (Xiphophorus helleri), a species not known to possess alarm pheromones and that is phylogenetically distant and allopatric from green sunfish. Sunfish significantly increased time spent freezing and time with dorsal fin rays erect (known antipredator postures) in response to conspecific skin extract but not to swordtail skin extract. No significant difference was noted in change in area use for sunfish exposed to conspecific versus swordtail skin extract. These results suggest that juvenile green sunfish possess chemical alarm signals. This is the first such demonstration in a centrarchid species.