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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

A nutritional evaluation of effluent grown algae and zooplakton as feed ingredients for Xiphohorous helleri, Poecilia reticulata and Poecilia velifera (Pisces : Poeciliidae)

Potts, Warren Mason January 1998 (has links)
The aim of this study was to evaluate the nutritional value of algae and zooplankton grown in an algal integrated ponding system for poeciliids. The available information on the nutritional requirements of poeciliids was compared with a proximate analysis of the algae and zooplankton. The effluent grown algae and zooplankton had a crude protein value of 41.47 ± 0.2% and 36.84 ± 0.3%, a lipid content of 4.8 ±. 0.4% and 11.1 ± 0.8% and a carbohydrate content of 35.13 ± 0.8% and 31.06 ± 0.6% respectively. These values compared favourably with those of the known nutritional requirements of poeciliids. To test if the nutritional value of the algae and zooplankton in the AlPS was constant, the species composition of the algae and the crude protein content of the algae and zooplankton in the high rate oxidation ponds were measured monthly and bi-weekly for a year respectively. The species composition remained fairly stable for the duration of the experiment and the average protein composition of the algae and zooplankton was 43.4 ± 4.4% and 38.6 ±2.8% respectively. This indicated that the algae and zooplankton in the AlPS provided high protein biomass through the year. The quality of the effluent grown algal and zooplankton biomass was evaluated by analysing their amino acid composition and comparing it with the amino acid composition of the body tissue of X. helleri. With respect to the amino acid composition of the body tissue of X. helleri, the amino acid profile of the algae had a 69% and the zooplankton a 63% similarity. The quality of the pure algal and zooplankton protein was also tested biologically, by feeding them directly to poeciliids during a ten week growth trial. The algae and zooplankton diets did not result in adequate growth compared to poeciliids which were fed a formulated control diet. The initial growth trial also evaluated the effect of processing on the chemical composition of the algae and its biological effect on fish fed with it. There were no significant differences in the chemical composition of fresh and sun dried algae and this was reflected in the growth rates of the fish which did not differ significantly. Freeze dried algae had a lower crude protein content than fresh and sun dried algae and a poorer amino acid composition. Fish fed freeze dried algae exhibited poorer growth and survival in comparison to the other treatments. The gut transit times of X. helleri and the gastric evacuation times of poeciliids were determined using colour dyes incorporated in the diet and by sacrificing fish at predetermined intervals after feeding respectively. The gut transit time of X. helleri fed a sun dried algal diet and a formulated diet was 225 ± 8.55 minutes and 261.93 ± 10.86 minutes respectively. The gastric evacuation times of X. helleri, P. reticu/ata and P. velifera were 7, 9 and 8 hours respectively. Since the maximum amount of food in the hindgut after feeding was detemined to be 3, 5 and 3 hours in X. helleri, P. reticulata and P. velifera respectively, fish were sacrificed at these times in the digestibility study. The digestibility of sun dried algae was determined using 1 % chromic oxide as an internal marker in the algae. The apparent crude protein digestibility of sun dried effluent grown algae ranged from 65%-75% in the three poeciliid species. Based on the results of the chemical and biological analysis of the algae and zooplankton, conventional diets incorporating algae at 5% and 20% protein inclusion levels were formulated. These diets and a treatment in which zooplankton, reared in the AlPS were fed as a dietary supplement to a formulated diet were fed to poeciliids for twelve weeks. No significant differences in the growth of poeciliids fed any of the test diets were observed. It was concluded that the algae could be incorporated into poeciliid formulated diets up to level of 20% protein inclusion without any negative effect on the growth of the fish. The chemical and biological evaluation of the algae suggested that it had a similar nutritional quality to soyabean meal. Poeciliid growth was not enhanced with a zooplankton supplement, however a possible low feeding rate by poeciliids on the zooplankton as a result of their small size may have affected the result. The colour enhancement potential of effluent grown algae and zooplankton was evaluated biologically in ten and twelve week growth trials using visual observation (31 people) and by using a chromameter. While pure, sun dried algae significantly enhanced the colour of P. reticulata, no significant differences in the colour of poeciliids were observed or recorded when fish were fed diets incorporating sun dried algae up to levels of 20% protein inclusion. The effect of effluent grown algae and zooplankton on poeciliid health was also tested biologically in the ten and twelve week growth trials. The high mortalities (75%-84%) recorded for X. hel/eri when fed the pure algal and zooplankton diets were considered to be as a result of the nutritional inadequacy of the diets since there were significantly less mortalities in fish fed the formulated control diet and 63% of the fish that died during the course of the trial were emaciated. In addition, fewer mortalities (10%-40%) were recorded in X. hel/eri fed the nutritionally adequate formulated diets in the twelve week growth trial. No symptoms of disease were recorded in the twelve week growth trial and the algae was considered to have no toxicological or pathological effects on poeciliids. Centrifugation, sand filtration, sedimentation, microstraining and biological harvest were evaluated as methods of small scale algal harvest from the high rate oxidation ponds. Algae could be harvested most efficiently with little associated labour by sedimentation (without flocculating agents) and by microstraining with 60IJm mesh. Effluent grown algae can replace conventional feed ingredients up to a level of 20% protein inclusion without negatively effecting the growth, colour, health or survival of poeciliids.
2

Reproductive isolation in some sympatric species of fishes

Liley, N. R. January 1963 (has links)
No description available.
3

The Influence of Somatic Investment on the Patterns of Reproduction in POECILIA LATIPINNA (Pisces: POECILIIDAE)

Wetherington, Jeffrey D. 01 July 1982 (has links) (PDF)
In Poecilia latipinna size-specific reproductive and survivorship patterns were correlated with changes in habitat availability. Of the numerous physical, chemical, and biological parameters associated with a reduction in available habitat, probably the most important was reduced food availability. Large (old) females, theoretically with a low reproductive value, allocated energy to reproduction regardless of habitat and, presumably, food availability. When reproductive activities were initiated in March, habitat availability was modest. In association with a severe reduction in available habitat in April, large females were subject to a substantial loss of body weight during the yolk-loading phase of the reproductive cycle. This loss, primarily of somatic tissue, was very costly and heavy mortality ensued. Habitat availability increased during late May and June and survivorship increased. By August the somatic condition of large females had improved significantly. As in April, yolk-leading resulted in a loss of body weight; however, the loss consisted of approximately 70% lipid. Although the cost was lower than April, the necessity of subsidizing reproduction with somatic tissue may account for the slight reduction in survivorship observed in September. Smaller (younger) females, theoretically with a higher reproductive value, allocated energy to reproduction in response to increases in habitat, and presumably food availability. This response was in the form of an increased number of small reproducing females and was not evident until the month following the increase in available habitat. In contrast to large females, reproductive activities among small females were initiated in April. In association with a severe reduction in habitat availability, small females were subject to a loss of dry weight during yolk-loading, which consisted of approximately 44% lipid. The cost of reproduction was reduced and survivorship improved relative to the large females. Despite an increase in available habitat in June, small females curtailed reproduction in favor of survival and increased fecundity afforded by a greater body size. By early August an increase in reproductive activities was evident among small females. The somatic condition of these females was significantly improved in comparison to April females. In contrast to large August females, small females did not subsidize reproduction with somatic tissue. The change in body weight was attributable to a loss of lipid. By early September the available habitat had increased dramatically. In comparison to August, the high number of small reproducing females suggested the response to improved conditions may be rapid. Changes in food availability and, thus the total energy budget (lower in spring, higher in the summer and fall) and the associated cost of reproduction (higher in spring, lower in fall) from April to September were not reflected by changes in fecundity. It appeared that under the conditions that prevailed during this study, a female that made a commitment to reproduction produced a size-specific brood of a fixed quality regardless of food availability and reproduction cost. If a female was able to assimilate excess energy during the gestation period, that energy was allocated in maintenance (i.e. repaying any somatic debt) and growth.
4

Phylogeography of the Livebearer Xenophallus umbratilis (Teleostei: Poeciliidae) : glacial cycles and sea level change predict diversification of a freshwater tropical fish /

Jones, Carissa P., January 2007 (has links) (PDF)
Project (M.S.)--Brigham Young University. Dept. of Biology, 2007. / Includes bibliographical references (p. 29-36).
5

Population Structure and Reproduction in the Introduced Florida Population of the Pike Killifish, BELONESOX BELIZANUS (Pisces: POECILIIDAE)

Turner, James S. 01 July 1981 (has links) (PDF)
The pike killifish, Belonesox belizanus Kner, is the largest member of the live-bearing family Poeciliidae. The species is native to Central America, and was introduced into Dade County, Florida in 1957. B. belizanus is primarily piscivorous, and has been identified as a potential ecological "problem" species for Florida due to its heavy predation on small native fishes, especially the mosquitofish (Gambusia affinis). The population structure and reproduction of the Florida population were investigated in this study from field samples and aquarium observations. The mean standard length (SL) of mature females was about 103 mm. Most females larger than 75 mm SL contained yolked developing ova, fertilized eggs, or embryos. Mature males averaged about 72 mm SL, and the majority of males larger than 55 mm SL were mature. The sex ratio of mature fish was significantly skewed in favor of females, while immature fish did not differ significantly from a 1:1 sex ratio. The average brood size of field-caught females was about 99, and there was a significant positive correlation of brood size with size of the parent female. The gross morphology of embryological development was described. Although mature unfertilized eggs, abnormal embryos, and degenerating embryos from a previous brood were found at a low frequency in broods of normal embryos, no evidence of superfetation was found. Sizes and weights of embryos and neonates were the largest reported for the family. There was a significant decrease in mean embryo weight as development proceeded, indicating that developing embryos received little or no nutrient input from the maternal system after fertilization. The average interbrood interval of aquarium-held females was 42 days, and females were capable of storing viable sperm. Field-caught females were capable of year-round reproduction. Laboratory-born neonates were immediately piscivorous, and exhibited distinctive behaviors associated with filling of the swim bladder and with avoiding detection by predators. Comparisons of the reproductive patterns of B. belizanus with other members of the family Peociliidae are discussed.
6

Life History Tactics of the Sailfin Molly (Poecilia Latipinna) in Contrasting Environments

Large, Helen L. 01 January 1985 (has links) (PDF)
Life history tactics of three Central Florida populations of Poecilia latipinna were compared to those predicted by life history selection theory. The three populations were sampled monthly for one year. At each sampling period a series of physicochemical measurements were taken to determine the degree of spatial and temporal environmental heterogeneity within each site. Life history traits determined for each population included size at maturity, size specific fecundity, reproductive effort, and length, weight, and condition of offspring. The population inhabiting the most variable environment was characterized by smaller size at maturity, lower size specific fecundity, lower overall reproductive output, and larger, more robust young. In all cases reproductive effort decreased with increasing female length, although the exact nature of this relationship varied between sites. The observed life history tactics do not fit the hypotheses of bet hedging or r-and K- selection theory, but support the idea that life history traits may vary independently rather than being inherited as coadapted units.
7

Anal Fin Pigmentation in <em>Brachyrhaphis</em> Fishes is Not Used for Sexual Mimicry

Hugentobler, Kandace Mary 01 July 2016 (has links)
Pigmentation patterns can be used as a communication signal in a variety of taxa, and can convey information relative to sexual selection, dominance, and species identification. Pigmentation is also sometimes used in mimicry to deceive the signal receiver into thinking the signaler is something other than itself. Mimicry can occur in several contexts, including sexual interactions, where one sex mimics another. There are relatively few examples of species with females that mimic males. Proposed hypotheses to explain female mimicry of males are that mimicry is used to reduce male harassment or that mimicry is used to display dominance over other females. In this study, we tested these two hypotheses using an experimental approach. Researchers have hypothesized that Brachyrhaphis fishes provide an example of sexual mimicry because females have pigmentation of the same coloration and shape, and in the same location as male genitalia. To test if female mimicry of males reduces male harassment, we designed an experiment to observe male preference for females with and without male-like pigmentation. To test the effect that female mimicry of males has on female dominance, we observed female behavior based on the pigmentation patterns of companion females. We found that neither of these hypotheses was supported by our data. We conclude that similarities in anal fin pigmentation between male and female Brachyrhaphis fishes cannot be explained as a way to reduce male harassment of females and is not a good predictor of female dominance interactions. Alternative explanations must exist for this pattern of anal fin coloration include the possibility that these similarities are simply non-adaptive.
8

Revisão taxonômica e filogenia do gênero Micropoecilia Hubbs (Cyprinodontiformes : Poeciliidae)

Sarraf , Alessandra 16 December 1998 (has links)
Submitted by Alberto Vieira (martins_vieira@ibest.com.br) on 2018-05-24T20:10:10Z No. of bitstreams: 1 273226.pdf: 9173980 bytes, checksum: 8c39758710b97486d106fac65e09c51e (MD5) / Made available in DSpace on 2018-05-24T20:10:11Z (GMT). No. of bitstreams: 1 273226.pdf: 9173980 bytes, checksum: 8c39758710b97486d106fac65e09c51e (MD5) Previous issue date: 1998-12-16 / CAPES / O monofiletismo do gênero Micropoecilia é sustentado por treze características sinapomórficas: ausência de projeção lateral no dentário; vômer alongado longitudinalmente; porção posterior do arco branquial dorsal não alongada; dentição do segundo faringobranquial reduzida; presença de processo na borda anterior do primeiro hipobranquial; processo latero-posterior do quinto ceratobranquial alongado; supracleitro reduzido; ossos do esqueleto caudal estreitos; primeira gonapófise levemente curvada ventralmente; ausência de elemento em forma de garra no raio cinco; nadadeira caudal de machos lanceolada; machos com mais raios na nadadeira dorsal que fêmeas e presença de mancha pós-umeral. São reconhecidas sete espécies: Micropoecilia parae (EINGEMANN), M. branneri (EIGENMANN), M. picta (REGAN), M. bifurca (EIGENMANN), M. minima (COSTA & SARRAF), M. sp. l e M. sp. 2. Micropoecilia picta é hipotetizada ser mais relacionada a M. parae por ambas possuírem processo ventral do pós-temporal diretamente ligado ao neurocrânio, ponta da nadadeira pélvica espessada... / Monophyly of the genus Micropoecilia is supported by 13 synapomorphic features: lateral projection of dentary absent; longitudinaly elongated vomer; non-elongated posterior portion of dorsal arch; reduced second pharyngobranchial dentition; process on the anterior border of first hypobranchial present; latero-posterior process of fifth ceratobranchial elongated; reduced supracleithrum; narrow bones of caudal skeleton; anterior portion of first gonapophisys gently curved ventrally; retrose claw at the tip of ray 5 absent; lanceolated caudal fin of males; males, with more dorsal-fin rays than females and post-umeral mark present. Seven species are recognized: Micropoecilia parae (EINGEMANN), M. branneri (EIGENMANN), M. picta (REGAN), M. bifurca (EIGENMANN), M. minima (COSTA & SARRAF), M. sp. 1 e M. sp. 2. Micropoecilia picta is hypothesized to be closely related to M. parae because both share 3 synapomorphies: between ventral process of posttemporal direct and firmly attached to neurocranium; thickened tip of the pelvic fin of males...
9

Revisão taxonômica e filogenia de Pamphorichtlys Regan, 1913 (Cyprinodontiformes ; Poeciliidae)

Figueiredo , Carlos Augusto Assumpção de 15 December 1997 (has links)
Submitted by Alberto Vieira (martins_vieira@ibest.com.br) on 2018-05-24T21:08:19Z No. of bitstreams: 1 278428.pdf: 18388610 bytes, checksum: e1b0221770d33669aec12d51863c54ce (MD5) / Made available in DSpace on 2018-05-24T21:08:19Z (GMT). No. of bitstreams: 1 278428.pdf: 18388610 bytes, checksum: e1b0221770d33669aec12d51863c54ce (MD5) Previous issue date: 1997-12-15 / CAPES / FUJB / Pamphorichthys é diagnosticado com base em vinte e sete caracteristicas apomórficas, principalmente das nadadeiras pélvicas. Entre as autapomorfias do gênero, onze são caracteres redutivos decorrentes da miniaturização das espécies. As espécies integrantes do gênero são: Pamphorichthys minor (Garman), P. scalpridens (Garman), P. hollandi (Henn), P. hasemani (Henn) e P. araguaiensis Costa. Limia heterandria Regan é confirmada como membro de Limia com base em três sinapomorfias, ao contrário de estar próxima a Pamphorichthys como sugerido por recentes autores. Pamphorichthys hasemani é o grupo irmão das demais espécies do gênero, que compõem uma tritomia formada por P. minor, P. araguaiensis e P. scalpridens + P. hollandi. A relação de grupo irmão entre Limia e Pamphorichthys é corroborada por quatro sinapomorfias, três delas observadas pela primeira vez. É feita uma diagnose osteológica das espécies do gênero e cada uma das cinco espécies envolvidas é redescrita e diagnosticada. São apresentados mapas de distribuição geográfica, listas de sinonímia para as espécies e um histórico resumido da sistemática do gênero e de cada espécie em particular. / Pamphorichthys diagnosis is based on twenty-seven apomorphic character states, mainly from the pelvic fins. Among the autapomorphies of the genus, eleven are reductive characters due to the species miniaturization. The included species are: Pamphorichthys minor (Garman), P. scalpridens (Garman), P. hollandi (Henn) and P. araguaiensis Costa Limia heterandria Regan is confirmed as a member of Limia based on three synapomorphies and not related to Pamphorichthys as suggested by recent authors. Pamphorichthys hasemani is the sister group of the other species in the genus, that comprises a trichotomy formed by Pamphorichthys minor, P. araguaiensis and P. scalpridens + P. hollandi. The sister group relationship between Limia and Pamphorichthys is corroborated by four synapomorphies, three of them are new. An osteological description of the genus' species is provided and each species is redescribed and diagnosed. Distribution maps, synonymy lists, and a brief history of the genus and each species systematics are also provided.
10

Intercohort cannibalism and parturition-associated behaviour of captive-bred swordtail, Xiphophorus helleri (Pisces: Poeciliidae)

Jones, Clifford Louis Wilshire January 2003 (has links)
Adult fish that belong to the family Poeciliidae cannibalise juveniles, both in the wild and under captive conditions, but this behaviour has only been partly investigated in the Poeciliidae in some of the commercially valuable species. The objective of the research is to develop an understanding of intercohort cannibalism and parturition-associated behaviour in captive-bred swordtail (Xiphophorus helleri), with applications to industry and future research of other poeciliids. Experiments investigating the effect of adult stocking density and sex ratio on the production of juveniles were used to determine if cannibalism occurs under culture conditions. The average rate of intercohort cannibalism ranged from (5.5 to 53.9%), and was positively density dependent and independent of sex ratio, indicating that males and females were probably equally cannibalistic. The highest number of juveniles (1725.7±141.4) produced per tank over 70 days was obtained from two males and eight females. To develop a better understanding of adult and juvenile behaviour during parturition, fish were observed under controlled laboratory conditions using video and behaviours such as attack (burst of speed by an adult in the direction of a juvenile), escape (avoidance of cannibalism after attack) and cannibalism (predation of a live juvenile by an adult), for example, were identified. Under laboratory conditions most young escaped in downward direction after attack (49%) and most utilised the refuge made that was made available. Furthermore, most attacks (62-65%) and cannibalism (57-84%) occurred at the bottom. Since the presence of refuge significantly increased the rate of juvenile survival under culture conditions, it was hypothesised that the rate of cannibalism could be reduced under farming conditions if juveniles were protected when they escaped downwards. This hypothesis was accepted as it was found that refuge at the bottom of the water column or the inclusion of a false-bottom reduced the rate of cannibalism by 49% and 72%, respectively. Similarly, the hypothesise that the rate of cannibalism could be reduced if juveniles where given protection when escaping sideways (32% of juveniles escaped sideways in the laboratory) was also accepted when tested under farm-scale conditions because a false-side reduced the rate of cannibalism by an average of 45%. Since males and females were equally responsible for cannibalising juveniles in the laboratory, it was hypothesised that the rate of cannibalism would decrease proportionately with the removal of males (Le. 20% of the cannibals) from the population; the removal of males under farming conditions resulted in a 19.5% reduction in the rate of cannibalism. Since older juveniles were better able to escape cannibalism than neonates and since adults habituate to stimuli that previously resulted in attack behaviour, it was hypothesised that the rate of cannibalism would remain unaffected by the length of time that juveniles were exposed to adults in the breeding tanks. This hypothesis was also accepted when tested under farm conditions. However, some hypotheses based on laboratory observations were not accepted. For example, a constant low light intensity did not appear to decrease the rate of cannibalism under farm conditions; also, the occurrence of dead and deformed juveniles went unnoticed in the laboratory, and under farm conditions, where adults did not have access to the bottom of the tank, 10% of the harvest consisted of dead and deformed juveniles. It is concluded that technologies, such as bottom-refuge or a false-side, that increase the size of the liveharvest and allow for the removal of potentially less viable offspring are recommended for the commercial production of poeciliids. The overall similarity of X. helleri behaviour between the laboratory experiments and the farm-scale trials suggests that the post-partum behaviour of X. helleri remains consistent under these different conditions; thus, behaviour under one set of conditions may be used to predict behaviour under other conditions. The application and significance of extrapolations to industry and future research of X. helleri and possibly other poeciliids were discussed and the most applicable laboratory observations with the highest extrapolation capacity were proposed. Furthermore, techniques were developed to aid industry and future researchers in making predictions relating to behaviour of X. helleri under different conditions based on laboratory observations. The results were used to develop a model indicating that selection pressures against cannibalism are not likely to exist at the rate of cannibalism observed here since the potential genetic gain through kin survival and inclusive fitness was shown to be greater than any potential genetiC loss experienced by a victim of cannibalism. The model was successfully tested under a range of social conditions. Other possible explanations for cannibalism in poeciliids, such as parental manipulation, nutritional advantages, opportunistic predation and the recovery of energy are discussed. It is suggested that the most likely proximate cause of cannibalism under captive conditions is opportunistic predation. The theory that cannibalism ensures that only viable genes of the victim are expressed, through inclusive fitness, is a possible ultimate cause of cannibalism, which may have been inherited from feral ancestors of captive-bred X. helleri.

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