Página 1 dos resultados de 31 itens digitais encontrados em 0.001 segundos

The critical swimming speed of Iberian barbel Barbus bocagei in relation to size and sex

Mateus, Catarina; Quintella, Bernardo R.; Almeida, Pedro R.
Fonte: Universidade de Évora Publicador: Universidade de Évora
Tipo: Artigo de Revista Científica Formato: 124845 bytes; application/pdf
ENG
Relevância na Pesquisa
28.01%
The swimming capacity of Barbus bocagei was measured with the critical swimming speed (Ucrit) standard test in a modified Blazka-type swim tunnel. Sixty B. bocagei were tested and they exhibited a mean S.D. Ucrit of 0.81 +/- 0.11 m/s or 3.1 +/- 0.86 total lengths per second (LT/s). Sex had no effect on Ucrit but significant differences were found between the swimming performance of fish with distinct sizes.

Laboratory protocol to calibrate sea lamprey (Petromyzon marinus L.) EMG signal output with swimming effort

Almeida, Pedro R.; Póvoa, Inês; Quintella, Bernardo R.
Fonte: Universidade de Évora Publicador: Universidade de Évora
Tipo: Artigo de Revista Científica Formato: 274704 bytes; application/pdf
ENG
Relevância na Pesquisa
17.45%
A correct application of electromyogram (EMG) telemetry in the field can be a powerful tool to evaluate activity patterns and swimming strategies of fishes. We evaluated the swim performance of seven untagged sea lampreys (Petromyzon marinus L.) with critical swim speed (Ucrit) tests. The average Ucrit observed was c. 1.03 ms–1 (i.e., 1.14 BL s–1). The strongest reotaxic response was observed during tests using water velocities between 0.4 ms–1 and 0.8 ms–1. During two consecutive years (i.e., 2004 and 2005), in order to model upstream migration of sea lampreys with CEMG transmitters (Lotek Wireless), we calibrated EMG signal with swim speed. A high correlation between EMG records and swim speed was observed in both years (r2 = 0.74– 0.93). However, in spite of methodology improvements and standardization in the second year of study, differences in intercepts and slopes were observed between individuals, making the determination of a unique calibration equation for all tagged animals unfeasible. Therefore, it appears to be necessary to obtain the relationship between EMG signals and swimming speed for each lamprey using laboratory procedures, prior to release in the wild. It is unknown whether this variability results from individual locomotor behaviour...

Critical swimming speed of two Iberian cyprinids: the Tagus nase Pseudochondrostoma polylepis and the bordallo Squalius carolitertii

Romão, F.; Quintella, B.R.; Pereira, T.; Alexandre, C.; Almeida, P.R.
Fonte: Wiley & Blackwell Publicador: Wiley & Blackwell
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
18.26%
The main purpose of this study was to gather swimming performance information for two endemic cyprinids of the Iberian Peninsula to contribute to the optimization of fish ways. Critical swimming speed (Ucrit) was determined for the Tagus nase Pseudochondrostoma polylepis (Steindachner, 1864) and for the bordallo Squalius carolitertii (Doadrio, 1988) in a swimming tunnel. From a total of 80 P. polylepis tested, the mean (± SD) Ucrit observed was 0.78 ± 0.15 ms-1 (c. 3.74 ± 0.93 BL s-1); the 68 S. carolitertii tested presented an Ucrit of 0.54 ± 0.1 ms-1 (c. 4.43 ± 0.74 BL s-1). Significant interspecific differences were found between the Ucrit of the tested cyprinids. Intraspecific comparisons between the Ucrit and the variables of size, sex, condition factor and gonado-somatic index were also made. No sex-or gonad maturation-related differences between the Ucrit were identified, but the robust P. polylepis were found to be stronger swimmers. Water velocities in fish ways for P. polylepis and S. carolitertii should aim, on average, for lower than 0.7 and 0.5 ms-1, respectively.

Critical swimming speed of yellow- and silver-phase European eel (Anguilla anguilla, L.).

Quintella, B.R.; Mateus, C.S.; Costa, J.L.; Domingos, I.; Almeida, Pedro R.
Fonte: Blackwell Verlag Publicador: Blackwell Verlag
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
18.01%
The prime objective of this study was to evaluate differences between the swimming performance of two distinct life stages of European eels. The critical swimming speed (Ucrit) of 29 yellow- and 33 silver-phase eels was evaluated in a swim tunnel. Silver-phase eels showed a better swimming performance (Ucrit = 0.66 ms/1) than yellow individuals (Ucrit = 0.43 ms/1). Male and female silver eels reached an identical Ucrit despite their different sizes, which may be a strategy to increase the synchronization of arrival at the spawning grounds.

Swimming performance of two Iberian cyprinids: the Tagus nase Pseudochondrostoma polylepis (Steindachner, 1864) and the bordallo Squalius carolitertii (Doadrio, 1988)

Romão, F.; Quintella, B.R.; Pereira, T.; Alexandre, C.; Almeida, Pedro R.
Fonte: Blackwell Verlag GmbH Publicador: Blackwell Verlag GmbH
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
18.26%
The main purpose of this study was to gather swimming performance information for two endemic cyprinids of the Iberian Peninsula to contribute to the optimization of fish ways. Critical swimming speed (Ucrit) was determined for the Tagus nase Pseudochondrostoma polylepis (Steindachner, 1864) and for the bordallo Squalius carolitertii (Doadrio, 1988) in a swimming tunnel. From a total of 80 P. polylepis tested, the mean (± SD) Ucrit observed was 0.78 ± 0.15 ms-1 (c. 3.74 ± 0.93 BL s-1); the 68 S. carolitertii tested presented an Ucrit of 0.54 ± 0.1 ms-1 (c. 4.43 ± 0.74 BL s-1). Significant interspecific differences were found between the Ucrit of the tested cyprinids. Intraspecific comparisons between the Ucrit and the variables of size, sex, condition factor and gonado-somatic index were also made. No sex-or gonad maturation-related differences between the Ucrit were identified, but the robust P. polylepis were found to be stronger swimmers. Water velocities in fish ways for P. polylepis and S. carolitertii should aim, on average, for lower than 0.7 and 0.5 ms-1, respectively.

Swimming performance and ecomorphology of the Iberian barbel Luciobarbus bocagei (Steindachner, 1864) on permanent and temporary rivers.

Almeida, Pedro R.; Alexandre, Carlos M.; Quintella, Bernardo R.; Ferreira, Ana Filipa; Romão, Filipe A.
Fonte: John Wiley & Sons Ltd Publicador: John Wiley & Sons Ltd
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
16.78%
Spatial variability in streamflow characteristics is responsible for a large range of habitat variations to which fish are adapted through life-cycle strategies and morphological adaptations. In this study, we compared the swimming performance and related morphology of two Iberian barbel populations from permanent and temporary rivers. The permanent river was characterised by its Atlantic influence with higher water availability and a more unstable and turbulent environment, contrasting with the lower discharge setting observed in the southern Mediterranean ecosystem during most of the hydrological year. Barbels from the permanent river exhibited a higher critical swimming speed (Ucrit) associated with a more fusiform body shape, narrower head and caudal peduncle, lower body condition and longer and higher pectoral and dorsal fins, when compared with the population from the temporary watercourse. These results reflect a morphological response in a way to reduce hydrodynamic resistance and energy expenditure during locomotion that we hypothesise here to be related with the different hydrological regimes of the studied systems.

Capacidade natatória e ecomorfologia de três espécies de bogas (Pseudochondrostoma polylepis, Pseudochondrostoma duriense, Pseudochondrostoma willkommii) em rios portugueses

Branca, Ricardo Xavier Mexia
Fonte: Universidade de Évora Publicador: Universidade de Évora
Tipo: Dissertação de Mestrado
POR
Relevância na Pesquisa
18.4%
Neste estudo determinou-se a velocidade crítica de natação (Ucrit), uma medida da capacidade natatória utilizada para espécies piscícolas, da Boga do Norte Pseudochondrostoma duriense (Coelho, 1985), Boga-comum Pseudochondrostoma polylepis (Steindachner 1864), e Boga do Guadiana Pseudochondrostoma willkommii (Steindachner 1866). As Ucrit foram relacionadas com a morfologia dos peixes e com as distintas características hidromorfológicas das três bacias hidrográficas de onde são originários os animais. A hipótese de trabalho pressupõe que rios com características hidromorfológicas distintas vão contribuir para a diferenciação morfológica e comportamental das espécies. As bogas-comuns foram as que apresentaram a Ucrit mais baixa (0,47 ± 0,06 m/s), enquanto as bogas do Norte (0,55 ± 0,09 m/s) e do Guadiana (0,54 ± 0,07 m/s) apresentaram uma Ucrit semelhante. Foram identificadas características morfológicas distintivas entre as espécies analisadas, com as bogas do Norte a apresentarem um corpo mais robusto e barbatanas maiores que os peixes das restantes duas espécies; Abstract: In this study, the critical swimming speed (Ucrit), a measure used to assess the swimming performance of fish, was determined for the northern straight-mouth nase Pseudochondrostoma duriense (Coelho...

Ontogeny of swimming behaviour of two temperate clingfishes, Lepadogaster lepadogaster and L. purpurea (Gobiesocidae)

Faria, Ana Margarida; Gonçalves, Emanuel João
Fonte: Inter-Research Publicador: Inter-Research
Tipo: Artigo de Revista Científica
Publicado em //2010 ENG
Relevância na Pesquisa
17.8%
Gobiesocids are typically reef-dwelling species whose larvae have been found in several nearshore rocky environments; this suggests a possible retention pattern for these species. Retention may occur due to the physical features of an area and/or active larval behaviour, such as swimming abilities. In the laboratory, we measured the ontogeny of swimming behaviour (routine speed and critical speed, Ucrit) of 2 clingfish species, Lepadogaster lepadogaster and L. purpurea. L. lepadogaster larvae swam better than L. purpurea larvae, but this difference might be related to differences in water temperature, since the former is a spring spawner, whereas the latter spawns during winter. It is well known that water viscosity increases with decreasing temperature, making swimming more difficult. Routine and critical swimming speeds of larvae of both species increased with ontogeny (size) despite high variability at any ontogenetic state. Ucrit ranged from 1 to 9.4 and 1.2 to 6.5 cm s–1 in L. lepadogaster and L. purpurea, respectively. Routine speeds were ~18 to 19% of the maximum Ucrit registered for both species. Interestingly, swimming speed started to decrease as settlement size (10 to 11 mm total length) was approached, concurrent with the development of a ventral sucking disk that allows individuals to attach to the bottom of the swimming chamber and counteract strong currents. This shift in swimming behaviour that is associated with settlement is probably an adaptation to the cryptobenthic mode of life of these fish.

Influence of starvation on the critical swimming behaviour during ontogenyof the Senegalese sole (Solea senegalensis) and its relationship with RNA/DNA ratios

Faria, Ana Margarida; Muha, Teja; Morote, Elvira; Chícharo, Maria Alexandra
Fonte: Institut de Ciències del Mar de Barcelona Publicador: Institut de Ciències del Mar de Barcelona
Tipo: Artigo de Revista Científica
Publicado em //2011 ENG
Relevância na Pesquisa
27.45%
Food availability can affect larval survival directly through starvation and indirectly through the effects on larval growth rate, swimming performance and vulnerability to predators. In the present study we evaluate the effects of starvation on growth, nutritional condition and swimming behaviour of the Senegalese sole (Solea senegalensis) throughout ontogeny (8 to 14 days after hatching). Biochemical analysis (RNA/DNA ratios) and behavioural experiments (critical swimming speed, Ucrit) were conducted on larvae reared under 3 feeding treatments: fed ad libitum, deprived of food for 48 hours and deprived of food for 96 hours. Growth was significantly affected by feeding treatment, while only slight decreases in RNA/DNA ratio and swimming performance were registered. Late stage larvae of the three feeding treatments had slower critical speeds than the pre-flexion and flexion stages, which is probably related to the benthic lifestyle acquired by the species at the end of the larval period. These physiological and behavioural changes are in accordance with previous results, which show that flatfish larvae are more resistant to starvation than pelagic species and that they become less active later in development.

Effects of starvation on swimming performance and body condition of pre-settlement Sparus aurata larvae

Faria, Ana Margarida da Silva; Chícharo, Alexandra; Gonçalves, Emanuel
Fonte: Universidade do Algarve Publicador: Universidade do Algarve
Tipo: Artigo de Revista Científica
Publicado em //2011 ENG
Relevância na Pesquisa
17.8%
Body condition in larval fishes is an important determinant of survival in the natural environment. However, few studies correlate body condition with behavioural traits critical for survival, such as swimming performance. In the present study, we compared normally fed larvae of gilthead seabream Sparus aurata Linnaeus, 1758, at various intervals post-hatch with larvae which were starved for 1 to 3 d (for Ucrit) or 2 d (for swimming endurance). Feeding treatment (fed and or unfed) had no effect on the relationship between Ucrit and larval size. However, in the endurance experiment, fed individuals swam twice as far as unfed larvae (19.7 km for fed larvae and 9.5 km for unfed larvae). The RNA/DNA ratio was higher in fed larvae in the Ucrit experiment, but significant effects were only detectable after a 3 d period of starvation. Fulton’s condition factor was significantly higher in fed larvae in the endurance trial, which suggests that growth (in weight) of starved larvae was affected by long-term swimming. Taken together, these results suggest that for aging and orientation behaviours (activities in which critical speeds might be involved) are not affected by reduced feeding over a few days, but that sub-lethal effects of starvation may affect dispersal potential (for which endurance swimming is critical) and therefore compromise subsequent recruitment to the adult population.

Influence of starvation on the critical swimming behaviour of the Senegalese sole (Solea senegalensis) and its relationship with RNA/DNA ratios during ontogeny

Faria, Ana Margarida da Silva; Muha, T.; Morote, E.; Chícharo, Alexandra
Fonte: Universidade do Algarve Publicador: Universidade do Algarve
Tipo: Artigo de Revista Científica
Publicado em //2011 ENG
Relevância na Pesquisa
16.78%
Food availability can affect larval survival directly through starvation and indirectly through the effects on larval growth rate, swimming performance and vulnerability to predators. In the present study we evaluate the effects of starvation on growth, nutritional condition and swimming behaviour of the Senegalese sole (Solea senegalensis) throughout ontogeny (8 to 14 days after hatching). Biochemical analysis (RNA/DNA ratios) and behavioural experiments (critical swimming speed, Ucrit) were conducted on larvae reared under 3 feeding treatments: fed ad libitum, deprived of food for 48 hours and deprived of food for 96 hours. Growth was significantly affected by feeding treatment, while only slight decreases in RNA/DNA ratio and swimming performance were registered. Late stage larvae of the three feeding treatments had slower critical speeds than the pre-flexion and flexion stages, which is probably related to the benthic lifestyle acquired by the species at the end of the larval period. These physiological and behavioural changes are in accordance with previous results, which show that flatfish larvae are more resistant to starvation than pelagic species and that they become less active later in development.

Ecologia do recrutamento de pequenos pelágicos: capacidades natatórias e condição nutricional de larvas de sardinha (Sardina pilchardus,Walbaum 1792)

Silva, Luís Miguel Ribeiro da
Fonte: Universidade do Algarve Publicador: Universidade do Algarve
Tipo: Dissertação de Mestrado
Publicado em //2012 POR
Relevância na Pesquisa
17.45%
Dissertação de mest., Biologia Marinha (Ecologia e Conservação), Faculdade de Ciências e Tecnologia, Univ. do Algarve, 2012; As capacidades de natação das larvas de pequenos pelágicos e a sua influência na sobrevivência e dispersão estão pouco estudadas. Pela primeira vez, descreveram-se as capacidades natatórias de larvas de Sardina pilchardus (Walbaum 1792), em condições controladas em laboratório desde a eclosão até ao 75º dia pós-eclosão (dpe). Comparou-se a capacidade natatória (velocidade crítica de natação (Ucrit) e comportamento) e a condição nutricional (índice RNA/DNA) de larvas cultivadas com 4 diferentes regimes alimentares. À eclosão, as larvas concentraram-se à superfície e após o 2º dpe começaram a dispersar pela coluna de água. As larvas recém-eclodidas passaram a maior parte do tempo inativas, tendo o tempo dispendido a nadar aumentado com a idade, estabilizando ao 30º dpe, sendo dispendendido a totalidade do tempo a nadar. Ao 15º dpe as larvas começaram a resistir a correntes de 1,5 cm s-1 por períodos curtos de tempo. A Ucrit aumentou significativamente ao longo da ontogenia, atingindo um máximo de 9,47 cm s-1 numa larva com 19,1 mm de comprimento total e 55 dpe. Não foram detetadas diferenças significativas das capacidades natatórias entre larvas cultivadas nas diferentes dietas para as idades comuns a todas as dietas. O número de ataques a presas e sequências completas de predação (desde a fixação ao ataque) aumentaram com a idade; ao 25º dpe o número de ataques foi inferior a 2 ataques min-1 e ao 60º dpe observaram-se em média 4 (±0...

Velocidade crítica de natação (Ucrit) de matrinxã (Brycon amazonicus) após exposição à hipoxia

Ferreira,Marcio Soares; Oliveira,Alzira Miranda de; Val,Adalberto Luis
Fonte: Instituto Nacional de Pesquisas da Amazônia Publicador: Instituto Nacional de Pesquisas da Amazônia
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/12/2010 PT
Relevância na Pesquisa
28.01%
A primeira resposta ao estresse é a fuga, que depende do desempenho natatório e de ajustes fisiológicos. Este estudo investigou a velocidade crítica de natação (Ucrit) de matrinxã após exposição à hipoxia. Para isso, os peixes foram expostos à hipoxia, sendo uma parte do grupo analisada antes e outra após natação forçada, por meio da Ucrit. A hipoxia resultou no aumento de lactato, glicose, cortisol e hematócrito. Mudanças nos níveis de sódio e potássio, bem como os valores de Ucrit não foram observadas. Sugere-se que o matrinxã seja sensível à hipoxia, mas os ajustes fisiológicos são suficientes para manter seu desempenho natatório.

Umidade crítica de compactação e densidade do solo máxima em resposta a sistemas de manejo num Latossolo Roxo

Figueiredo,L. H. A.; Dias Junior,M. S.; Ferreira,M. M.
Fonte: Sociedade Brasileira de Ciência do Solo Publicador: Sociedade Brasileira de Ciência do Solo
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/09/2000 PT
Relevância na Pesquisa
17.8%
O termo compactação do solo refere-se à compressão do solo não saturado durante a qual existe um aumento da densidade do solo em conseqüência da redução de seu volume, pela expulsão do ar causado pelo manejo inadequado. Com o objetivo de estudar o efeito de diferentes sistemas de manejo na densidade do solo máxima (Ds máx), e na umidade crítica de compactação (Ucrít), realizou-se um experimento em um Latossolo Roxo da Região de Lavras (MG), submetido aos seguintes sistemas de manejo: preparo com arado de discos (AD), preparo com escarificador (CM), semeadura direta (SD), preparo com arado de aivecas (AA) e preparo intensivo com grade (GD). O experimento foi instalado, em novembro de 1994, em blocos casualizados. Foram realizadas três amostragens em 1996: em janeiro, antes da semeadura do feijão; em abril, antes da colheita do feijão, e em novembro, antes da semeadura do milho. As amostras deformadas foram coletadas nas camadas de 0-0,07 e 0,20-0,27 m de profundidade nos sistemas de manejo AD, CM e AA. No sistema de manejo SD, as amostras deformadas foram coletadas nas camadas de 0-0,07 e 0,25-0,32 m de profundidade e, no caso do sistema GD, nas camadas de 0-0,07 e 0,15-0,22 m de profundidade. A partir das curvas de compactação...

Temperature- and exercise-induced gene expression and metabolic enzyme changes in skeletal muscle of adult zebrafish (Danio rerio)

McClelland, Grant B; Craig, Paul M; Dhekney, Kalindi; Dipardo, Shawn
Fonte: Blackwell Science Inc Publicador: Blackwell Science Inc
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
16.78%
Both exercise training and cold acclimatization induce muscle remodelling in vertebrates, producing a more aerobic phenotype. In ectothermic species exercise training and cold-acclimatization represent distinct stimuli. It is currently unclear if these stimuli act through a common mechanism or if different mechanisms lead to a common phenotype. The goal of this study was to survey responses that represent potential mechanisms responsible for contraction- and temperature-induced muscle remodelling, using an ectothermic vertebrate. Separate groups of adult zebrafish (Danio rerio) were either swim trained or cold acclimatized for 4 weeks. We found that the mitochondrial marker enzyme citrate synthase (CS) was increased by 1.5× in cold and by 1.3× with exercise (P < 0.05). Cytochrome c oxidase (COx) was increased by 1.2× following exercise training (P < 0.05) and 1.2× (P = 0.07) with cold acclimatization. However, only cold acclimatization increased β-hydroxyacyl-CoA dehydrogenase (HOAD) compared to exercise-trained (by 1.3×) and pyruvate kinase (PK) relative to control zebrafish. We assessed the whole-animal performance outcomes of these treatments. Maximum absolute sustained swimming speed (Ucrit) was increased in the exercise trained group but not in the cold acclimatized group. Real-time PCR analysis indicated that increases in CS are primarily transcriptionally regulated with exercise but not with cold treatments. Both treatments showed increases in nuclear respiratory factor (NRF)-1 mRNA which was increased by 2.3× in cold-acclimatized and 4× in exercise-trained zebrafish above controls. In contrast...

The effects of temperature and exercise training on swimming performance in juvenile qingbo (Spinibarbus sinensis)

Pang, Xu; Yuan, Xing-Zhong; Cao, Zhen-Dong; Fu, Shi-Jian
Fonte: Springer-Verlag Publicador: Springer-Verlag
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
18.34%
To investigate the effects of temperature and exercise training on swimming performance in juvenile qingbo (Spinibarbus sinensis), we measured the following: (1) the resting oxygen consumption rate documentclass[12pt]{minimal} usepackage{amsmath} usepackage{wasysym} usepackage{amsfonts} usepackage{amssymb} usepackage{amsbsy} usepackage{mathrsfs} usepackage{upgreek} setlength{oddsidemargin}{-69pt} egin{document}$$ left( {{dot{ ext{M}} ext{O}}_{{ 2 { ext{rest}}}} } ight) $$end{document}, critical swimming speed (Ucrit) and active oxygen consumption rate documentclass[12pt]{minimal} usepackage{amsmath} usepackage{wasysym} usepackage{amsfonts} usepackage{amssymb} usepackage{amsbsy} usepackage{mathrsfs} usepackage{upgreek} setlength{oddsidemargin}{-69pt} egin{document}$$ left( {{dot{ ext{M}} ext{O}}_{{ 2 { ext{active}}}} } ight) $$end{document} of fish at acclimation temperatures of 10, 15, 20, 25 and 30 °C and (2) the documentclass[12pt]{minimal} usepackage{amsmath} usepackage{wasysym} usepackage{amsfonts} usepackage{amssymb} usepackage{amsbsy} usepackage{mathrsfs} usepackage{upgreek} setlength{oddsidemargin}{-69pt} egin{document}$$ dot{M}{ ext{O}}_{{ 2 { ext{rest}}}} $$end{document}...

The Effect of Drag and Attachment Site of External Tags on Swimming Eels: Experimental Quantification and Evaluation Tool

Tudorache, Christian; Burgerhout, Erik; Brittijn, Sebastiaan; van den Thillart, Guido
Fonte: Public Library of Science Publicador: Public Library of Science
Tipo: Artigo de Revista Científica
Publicado em 19/11/2014 EN
Relevância na Pesquisa
17.8%
Telemetry studies on aquatic animals often use external tags to monitor migration patterns and help to inform conservation effort. However, external tags are known to impair swimming energetics dramatically in a variety of species, including the endangered European eel. Due to their high swimming efficiency, anguilliform swimmers are very susceptibility for added drag. Using an integration of swimming physiology, behaviour and kinematics, we investigated the effect of additional drag and site of externally attached tags on swimming mode and costs. The results show a significant effect of a) attachment site and b) drag on multiple energetic parameters, such as Cost Of Transport (COT), critical swimming speed (Ucrit) and optimal swimming speed (Uopt), possibly due to changes in swimming kinematics. Attachment at 0.125 bl from the tip of the snout is a better choice than at the Centre Of Mass (0.35 bl), as it is the case in current telemetry studies. Quantification of added drag effect on COT and Ucrit show a (limited) correlation, suggesting that the Ucrit test can be used for evaluating external tags for telemetry studies until a certain threshold value. Uopt is not affected by added drag, validating previous findings of telemetry studies. The integrative methodology and the evaluation tool presented here can be used for the design of new studies using external telemetry tags...

Intraspecific variation in aerobic and anaerobic locomotion: gilthead sea bream (Sparus aurata) and Trinidadian guppy (Poecilia reticulata) do not exhibit a trade-off between maximum sustained swimming speed and minimum cost of transport

Svendsen, Jon C.; Tirsgaard, Bjørn; Cordero, Gerardo A.; Steffensen, John F.
Fonte: Frontiers Media S.A. Publicador: Frontiers Media S.A.
Tipo: Artigo de Revista Científica
Publicado em 17/02/2015 EN
Relevância na Pesquisa
17.8%
Intraspecific variation and trade-off in aerobic and anaerobic traits remain poorly understood in aquatic locomotion. Using gilthead sea bream (Sparus aurata) and Trinidadian guppy (Poecilia reticulata), both axial swimmers, this study tested four hypotheses: (1) gait transition from steady to unsteady (i.e., burst-assisted) swimming is associated with anaerobic metabolism evidenced as excess post exercise oxygen consumption (EPOC); (2) variation in swimming performance (critical swimming speed; Ucrit) correlates with metabolic scope (MS) or anaerobic capacity (i.e., maximum EPOC); (3) there is a trade-off between maximum sustained swimming speed (Usus) and minimum cost of transport (COTmin); and (4) variation in Usus correlates positively with optimum swimming speed (Uopt; i.e., the speed that minimizes energy expenditure per unit of distance traveled). Data collection involved swimming respirometry and video analysis. Results showed that anaerobic swimming costs (i.e., EPOC) increase linearly with the number of bursts in S. aurata, with each burst corresponding to 0.53 mg O2 kg−1. Data are consistent with a previous study on striped surfperch (Embiotoca lateralis), a labriform swimmer, suggesting that the metabolic cost of burst swimming is similar across various types of locomotion. There was no correlation between Ucrit and MS or anaerobic capacity in S. aurata indicating that other factors...

Production of Ethanol in Aerobically Trained Goldfish (Carassius auratus)

Mileva, Gerri
Fonte: Quens University Publicador: Quens University
Tipo: Tese de Doutorado Formato: 399180 bytes; application/pdf
EN
Relevância na Pesquisa
17.45%
Goldfish produce ethanol under hypoxic and anoxic conditions and when exercised under anaerobic conditions. In this study the effect of aerobic training on the ethanol production of goldfish was examined. First Ucrit was determined (5.50bl s-1) and then fish were trained at 70% Ucrit for 14 days. Ethanol concentration (mmol kg-1) in resting aerobically trained fish muscle (0.158± 0.07mmol kg-1) was similar to samples of trained fish muscle after anaerobic exercise (0.141±0.02mmol kg-1; Students T-test, Df=1, p=0.73). Lactate concentration (μmol g-1) in resting aerobically trained muscle was also similar to trained muscle after anaerobic exercise and untrained resting muscle (One-way ANOVA, Df= 20, p=0.2119). There was a significant decrease in liver lactate concentration between the untrained resting and the two trained treatments (One-way ANOVA, Df= 20, p=0.001) suggesting an increase in lactate clearance of the trained fish. Because concentrations of ethanol and lactate in muscle did not increase after anaerobic exercise, aerobic training may have had an effect on the goldfish. We believe that aerobic training increased the lactate clearance of the liver and decreased the ethanol production of the muscle after exercise. This is especially evident when compared to previous literature values of untrained fish exercised under anaerobic conditions.

Evaluating the effects of ocean acidification on sand-smelt larvae through biochemical biomarkers and swimming ability

Silva, Cátia Sofia Esteves da
Fonte: Instituto Universitário de Ciências Psicológicas, Sociais e da Vida Publicador: Instituto Universitário de Ciências Psicológicas, Sociais e da Vida
Tipo: Dissertação de Mestrado
Publicado em //2015 ENG
Relevância na Pesquisa
27.8%
Dissertação de Mestrado apresentada ao ISPA - Instituto Universitário; A acidificação oceânica é um problema global, cujos efeitos são ainda pouco estudados. Com maior foco de investigação em organismos com exoesqueleto calcário, pouca atenção tem sido dada ao potencial impacto noutros processos e componentes do ecossistema, como o caso dos estágios iniciais do ciclo de vida de outros organismos, como os peixes. Neste sentido, o principal objetivo deste estudo foi investigar os efeitos da exposição a elevadas concentrações de pCO2 no comportamento, desenvolvimento e metabolismo das fases larvares do peixe-rei, Atherina presbyter. As larvas em estado de desenvolvimento de flexão e pós-flexão foram capturadas no parque marinho da Arrábida, Portugal, e mantidas em condições controladas com diferentes níveis de pCO2 (Controlo: ~600μatm; Médio: ~1000μatm; Elevado: ~1800μatm) entre 7-15 dias, antes da sua velocidade crítica de natação (Ucrit) ser testada. Adicionalmente, foram determinados dados morfométricos e biomarcadores bioquímicos relacionados com stress oxidativo (SOD, CAT, LPO, danos no DNA e ROS) e metabolismo energético (ETS, LDH, IDH e Hidratos de Carbono). Os resultados sugerem que o comportamento natatório das larvas não é afectado pela exposição a elevados níveis de CO2; no entanto os resultados bioquímicos apoiam a hipótese de que elevados custos energéticos poderão estar associados a alterações morfométricas...