Disturbance events occur outside the normal disturbance regime of a system and can cause changes in behavior of some organisms. The 2010 cold event is an example of a disturbance event that influenced the behavior of Common Snook (Centropomus undecimalis). Common snook are euryhaline sportfish native to Florida, Texas, and the Caribbean. Florida is the northern most part of their distribution, based on the 15o C winter isotherm. They move between offshore areas during spawning season and freshwater coastal rivers during non-spawning season. With the use of previously collected acoustic telemetry and biological data this project identifies the impact on population dynamics and movement near the time of the event. The goal is to understand fine scale movements and physiological conditions under normal and abnormal conditions to further inform management of the species. / Includes bibliography. / Thesis (M.S.)--Florida Atlantic University, 2018. / FAU Electronic Theses and Dissertations Collection

Os peixes são organismos plásticos em relação às alterações de ciclos ambientais como o ciclo claro/escuro e ciclo de disponibildade alimentar, zeitgebers comprovadamente fortes para outros organismos vertebrados. O objetivo geral deste estudo foi verificar se o ciclo claro /escuro (CE) e o ciclo de disponibilidade alimentar (AJ) promovem sincronização da atividade locomotora em exemplares de robalos juvenis das espécies Centropomus parallelus e C. undecimalis coletados na região do Sistema Cananéia-Iguape (SP). Foi verificada uma possível relação hierárquica entre estes ciclos ambientais, e também foram observadas diferenças inter e intraindividuais de sincronização. Depois de coletados os peixes permaneceram em aquários do Laboratório de Ritmos Biológicos do GMDRB (Grupo Multidisciplinar de Desenvolvimento e Ritmos Biológicos) com temperatura da água entre 25 e 30oC, salinidade entre 20 a 30‰ e ciclos claro/escuro de 11:13h e 13:11h. A alimentação foi administrada manualmente, a intensidade luminosa da fase clara foi de 90lux e da fase escura foi de 10lux. A atividade locomotora dos peixes foi registrada individualmente através das interrupções nos feixes de luz infra-vermelha. Os feixes foram gerados por emissores de luz e detectados por fotocélulas; os pares emissor-fotocélula foram distribuídos na superfície e fundo dos aquários. A interrupção foi convertida em pulso elétrico por uma interface digital. Os dados foram processados através do programa “El Temps"(Diez-Noguera, 1999); foram confeccionados actogramas, periodogramas de Lomb-Scargle e plexogramas. Foram calculadas as porcentagens de alocação da atividade locomotora em cada fase (claro, escuro, jejum e alimentação) baseadas no número total de horas da fase correspondente. As porcentagens foram então comparadas em todas as condições experimentais, para todos os indivíduos. As comparações foram feitas através do teste Z com correção de Yates, com o auxílio do programa estatístico “SigmaStat" versão 3.11. Diante dos resultados obtidos pôde-se concluir que somente o ciclo claro /escuro foi capaz de sincronizar alguns dos exemplares testados neste estudo. O mascaramento promovido por este ciclo ambiental possivelmente é responsável pela plasticidade temporal e reflete a complexidade do ambiente costeiro repleto de ciclos ambientais. / Fish are generally adaptable to changes in environmental cycles such as the light/dark cycle (LD) and food availability cycle (EF). These cycles are the most common and considered strong zeitgebers for vertebrates. The aim of this study was to investigate whether LD and EF cycles were able to synchronize the locomotor activity of juvenile snooks (Centropomus undecimalis and C. parallelus) collected at Cananéia estuary (São Paulo – Brazil). Juvenile fish were kept in a laboratory lightproof room (Laboratório de Ritmos Biológicos do GMDRB-Grupo Multidisciplinar de Desenvolvimento e Ritmos Biológicos), water temperature between 25 and 30oC, salinity between 20 and 30‰. Feeding was performed manually. A bulb of a blue light was located at the top of aquaria (90lx in the light phase and 10lx in the dark phase). Locomotor activity was detected by six (eight, depending on aquaria) pairs of infrared sensors distributed on the surface and at the bottom of aquaria. Data collected from the infrared sensors were analyzed through the program “El Temps". Actograms, Lomb-Scargle periodograms, and plexograms were drawn. Locomotor activity percentages were calculated for the different phases of the cycles and compared in all experimental manipulations for all indivuduals. The comparisions were calculated using the software “SigmaStat" version 3.11 through the test Z with Yates correction. We concluded that the LD cycle syncronized (probably masking) the locomotor activity in some juvenile fish studied whereas the EF cycle did not. We discuss the temporal plasticity observed in the context of the complexity of coastal environmental.

Os peixes são organismos plásticos em relação às alterações de ciclos ambientais como o ciclo claro/escuro e ciclo de disponibildade alimentar, zeitgebers comprovadamente fortes para outros organismos vertebrados. O objetivo geral deste estudo foi verificar se o ciclo claro /escuro (CE) e o ciclo de disponibilidade alimentar (AJ) promovem sincronização da atividade locomotora em exemplares de robalos juvenis das espécies Centropomus parallelus e C. undecimalis coletados na região do Sistema Cananéia-Iguape (SP). Foi verificada uma possível relação hierárquica entre estes ciclos ambientais, e também foram observadas diferenças inter e intraindividuais de sincronização. Depois de coletados os peixes permaneceram em aquários do Laboratório de Ritmos Biológicos do GMDRB (Grupo Multidisciplinar de Desenvolvimento e Ritmos Biológicos) com temperatura da água entre 25 e 30oC, salinidade entre 20 a 30‰ e ciclos claro/escuro de 11:13h e 13:11h. A alimentação foi administrada manualmente, a intensidade luminosa da fase clara foi de 90lux e da fase escura foi de 10lux. A atividade locomotora dos peixes foi registrada individualmente através das interrupções nos feixes de luz infra-vermelha. Os feixes foram gerados por emissores de luz e detectados por fotocélulas; os pares emissor-fotocélula foram distribuídos na superfície e fundo dos aquários. A interrupção foi convertida em pulso elétrico por uma interface digital. Os dados foram processados através do programa “El Temps”(Diez-Noguera, 1999); foram confeccionados actogramas, periodogramas de Lomb-Scargle e plexogramas. Foram calculadas as porcentagens de alocação da atividade locomotora em cada fase (claro, escuro, jejum e alimentação) baseadas no número total de horas da fase correspondente. As porcentagens foram então comparadas em todas as condições experimentais, para todos os indivíduos. As comparações foram feitas através do teste Z com correção de Yates, com o auxílio do programa estatístico “SigmaStat” versão 3.11. Diante dos resultados obtidos pôde-se concluir que somente o ciclo claro /escuro foi capaz de sincronizar alguns dos exemplares testados neste estudo. O mascaramento promovido por este ciclo ambiental possivelmente é responsável pela plasticidade temporal e reflete a complexidade do ambiente costeiro repleto de ciclos ambientais. / Fish are generally adaptable to changes in environmental cycles such as the light/dark cycle (LD) and food availability cycle (EF). These cycles are the most common and considered strong zeitgebers for vertebrates. The aim of this study was to investigate whether LD and EF cycles were able to synchronize the locomotor activity of juvenile snooks (Centropomus undecimalis and C. parallelus) collected at Cananéia estuary (São Paulo – Brazil). Juvenile fish were kept in a laboratory lightproof room (Laboratório de Ritmos Biológicos do GMDRB-Grupo Multidisciplinar de Desenvolvimento e Ritmos Biológicos), water temperature between 25 and 30oC, salinity between 20 and 30‰. Feeding was performed manually. A bulb of a blue light was located at the top of aquaria (90lx in the light phase and 10lx in the dark phase). Locomotor activity was detected by six (eight, depending on aquaria) pairs of infrared sensors distributed on the surface and at the bottom of aquaria. Data collected from the infrared sensors were analyzed through the program “El Temps”. Actograms, Lomb-Scargle periodograms, and plexograms were drawn. Locomotor activity percentages were calculated for the different phases of the cycles and compared in all experimental manipulations for all indivuduals. The comparisions were calculated using the software “SigmaStat” version 3.11 through the test Z with Yates correction. We concluded that the LD cycle syncronized (probably masking) the locomotor activity in some juvenile fish studied whereas the EF cycle did not. We discuss the temporal plasticity observed in the context of the complexity of coastal environmental.

Submitted by Mario BC (mario@bc.ufrpe.br) on 2017-09-26T12:29:32Z No. of bitstreams: 1 Julio Guazzelli Gonzalez.pdf: 1334638 bytes, checksum: ee31010a89892f79699e9228c2becee6 (MD5) / Made available in DSpace on 2017-09-26T12:29:32Z (GMT). No. of bitstreams: 1 Julio Guazzelli Gonzalez.pdf: 1334638 bytes, checksum: ee31010a89892f79699e9228c2becee6 (MD5) Previous issue date: 2017-02-22 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / Stable isotopes analysis of carbon (δ13C) and nitrogen (δ15N) was used to access the trophic ecology and resource use of two economically important estuarine fishes, the common (Centropomus undecimalis) and fat snook (Centropomus parallelus) at four tropical estuaries, northeast Brazil. Factors like studied location and season were analysed to verify potential influences on these process. Results of δ13C and δ15N shows that snooks exhibits a dynamic resource use across studied locations, with stronger resource partitioning at smaller systems. Overall, fishes were classified between the second and third trophic position and rely on a mixture of available sources which varies according to estuary. Seasonality also showed to be an important factor for species trophic ecology, with greater overlaps in the isotopic niche and boarder use of resources available. Our findings suggests that the two sympatric snooks share, at least in part, the same resources. However, it is unlikely that this represents a limiting factor for the stock, since snooks present an opportunistic behaviour among estuaries and seasons. Further, our results highlights the importance of seasonality to snook’s trophic ecology by providing similar and more abundant resources at the rainy season. This work provide new and insightful information about the influence of estuary’s typology on the interaction of two high-value predators. / A análise de isótopos estáveis de carbono (δ13C) e nitrogênio (δ15N) foi utilizada para acessar a ecologia trófica e o uso de recursos de dois peixes estuarinos economicamente importantes, o camurim açu (Centropomus undecimalis) e camurim branco (Centropomus parallelus), em quatro estuários tropicas, nordeste do Brasil. Fatores como a área de estudo e estação do ano foram analisados para verificar o possível efeito sobre estes processos. Os resultados de δ13C e δ15N demonstram que os camurins exibem um dinâmico processo de partição de recursos entre os estuários estudados, com maior intensidade em estuários menores. De modo geral, os peixes foram classificados entre a segunda e terceira posição trófica e dependem de uma mistura de fontes disponívies que varia de acordo com estuário. A sazonalidade também demonstrou ser um importante fator para a ecologia trófica das espécies, com maiores sobreposições no nicho isotópico e um uso mais amplo dos recursos disponíveis. Nossas descobertas sugerem que as duas espécies simpátricas de camurim compartilham, pelo menos em partes, os mesmos recursos. Entretanto, é improvável que isto represente um fator limitante para o estoque populacional, uma vez que os camurins apresentaram um comportamento oportunista entre os estuários e estações do ano. Ademais, nossos resultados chamam atenção para a importância da sazonalidade sobre a ecologia trófica dos camurins, proporcionando recursos similares e mais abundantes durante a estação chuvosa. Este estudo traz informações novas e intuitivas sobre a influência da morfologia do estuário sobre a interação de dois predadores com alto valor comercial.

Submitted by Mario BC (mario@bc.ufrpe.br) on 2017-10-30T12:49:02Z No. of bitstreams: 1 Reginaldo Florencio da Silva Junior.pdf: 1573897 bytes, checksum: 6b4cdfaa9a70f1efb155726c3d8b7512 (MD5) / Made available in DSpace on 2017-10-30T12:49:02Z (GMT). No. of bitstreams: 1 Reginaldo Florencio da Silva Junior.pdf: 1573897 bytes, checksum: 6b4cdfaa9a70f1efb155726c3d8b7512 (MD5) Previous issue date: 2016-02-19 / Conselho Nacional de Pesquisa e Desenvolvimento Científico e Tecnológico - CNPq / The massive growth of aquaculture and limited supply of fish meal, means that alternative sources of food need to be studied to make more sustainable industry. In this context, the apparent digestibility coefficients (ADC) eight ingredients used in the aquafeeds were determined in terms of dry matter (DM), crude protein (CP), ether extract (EE), mineral contente (MM), phosphorus (P), gross energy (GE) and amino acids (AA) in juvenile common snook (Centropomus undecimalis) using chromium oxide as inert marked. The ingredients included fish meal (FM), shrimp meal (CM), poultry by-products (PBP), hydrolyzed feather meal (HFM), soybean meal (SM), corn gluten meal (CGM) wheat bran (WB) and maize (M). A reference diet (56.7%CP, 22.7 MJ/kg GE) was formulated in parallel experimental diets which included 30% of each ingredient and 70% of the reference diet. The results indicated that the ADC of nutrients and GE were affected (P <0.05) by the test composition ingredients. The CGM and HFM showed similar results (P> 0.05) in nutrients and GE. The digestibility DM ranges from 83% (SM) to 145% (CGM). The EE was well digested by fish with differences (P>0.05) among the ingredients. The smaller ADC MM were observed in the PBP (37%) and SM (28%) and difference (P<0.05) among the treatments. The ADC GE in the FM (118%) and SM (117%) were significantly higher (P<0.05) than the other ingredients for common snook. The ADC P were higher in all the ingredients. The ADC of AA reflected the digestibility of CP, and FM, SM, HFM and CGM greater than PBP, SM and M. The results of this study indicate high digestibility of protein and energy ingredients for juvenile C. undecimalis. However, the digestibility of mineral content to PBP, SM and M were significantly lower FM, CM, HFM, CGM, SM and WB, indicating the potential use of these ingredients in feed for this species. Thus, this study also investigated the effects of a commercial diet (I) and experimental on profile of digestive enzymes in C. undecimalis. The activities of peptidases, acid and alkaline, showed differences (P<0.05) between the fish fed the diets. The analysis differ (P<0.05) between treatments with greater intensity in the diets I, FM and HFM. In studies with trypsin, there is difference (P<0.05), with higher enzyme activity in fish fed diet I. Chymotrypsin showed higher proportion of enzymes in diets with protein ingredients, except for the PBP in relation to energy. Amylase, it was also high in protein ingredients except CGM. There was no difference (P>0.05) for specific activity of pepsin. The different ether extract concentrations in the diet REF and consequently in the other experimental diets, inhibited total alkaline proteolytic activities and trypsin in juveniles de common snook. The identification and characterization of acidic and alkaline proteases in fish digestibility studies is an important step in understanding the digestive mechanisms. The results of this thesis will allow the formulation of experimental and commercial diets based on digestible nutrients for juvenile common snook. / Os coeficientes de digestibilidade aparente (CDA) de oito ingredientes utilizados na indústria aquícola foram determinados em termos de matéria seca (MS), proteína bruta (PB), extrato etéreo (EE), matéria mineral (MM), fósforo (P), energia bruta (EB) e aminoácidos (AA) em juvenis de robalo-flecha (Centropomus undecimalis), utilizando óxido de cromo como marcado inerte. Os ingredientes incluíam a farinha de peixe (FP), farinha de camarão (FC), farinha de vísceras de aves (FVA), farinha de penas hidrolisada (FPH), farelo de soja (FS), farelo de glúten de milho (FGM), farelo de trigo (FT) e farinha de milho (FM). Uma dieta referência (REF) (56,7%PB, 22,7 MJ/kg ED) foi formulada em paralelo as dietas experimentais que incluiu 30% de cada ingrediente e 70% da dieta referência. Os resultados indicaram que o CDA dos nutrientes e EB foram afetados (P<0,05) pela composição dos ingredientes testes. O FGM e FPH apresentaram resultados semelhantes (P>0,05) nos nutrientes e EB. A digestibilidade da MS variou de 83% (FS) a 145% (FGM). O EE foi bem digerido pelos peixes com diferenças (P>0,05) entre os ingredientes. Os menores CDA de MM observados na FVA (37%), FS (28%) e FM (47,8%) com diferença (P<0,05) entre os tratamentos. Os CDA de EB na FP (118%) e FC (117%) foram significativamente maiores (P<0,05) do que os demais ingredientes utilizados para os robalo-flecha. Os CDA do P foram altos em todos os ingredientes. Os CDA dos AAs refletiram a digestibilidade da PB, sendo a FP, FC, FPH e FGM maior que FVA, FS e FM. Os resultados deste estudo indicam alta digestibilidade dos ingredientes proteicos e energéticos para juvenis de C. undecimalis. No entanto, a digestibilidade da matéria mineral para FVA, FS e FM, foram bastante inferiores a FP, FC, FPH, FGM e FT, indiciando potencial uso desses ingredientes em rações para essa espécies. Para melhorar a utilização das dietas em peixes, além da digestibilidade dos ingredientes é importante que se conheça o perfil de enzimas digestivas do animal cultivado. Assim, este trabalho também investigou os efeitos de uma dieta comercial (I) e experimentais sobre o perfil das enzimas digestivas em juvenis de C. undecimalis. As atividades das proteases ácidas e alcalinas, mostraram diferença (P<0,05) entre os peixes alimentados com as dietas. A análise diferiu (P<0,05) entre os tratamentos com maior intensidade nas dietas I, FP e FPH. Nos estudos com a tripsina, observa-se diferença (P<0,05), com maior atividade enzimática nos peixes alimentados com a dieta I. A quimotripsina, mostrou maior atividade de enzimas nas dietas com ingredientes proteicos, exceto para a FVA, em relação aos energéticos. A amilase, também se mostrou alta nos ingredientes proteicos, exceto FGM. Não houve diferença (P>0,05) para atividade específica da pepsina. As diferentes concentrações de extrato etéreo na dieta (REF) e consequentemente nas demais dietas experimentais, inibiram as atividades proteolítica alcalina total e de tripsina nos juvenis de robalo-flecha. A identificação e caracterização das proteases ácidas e alcalinas em estudos de digestibilidade de peixe é um passo importante para a compreensão dos mecanismos digestivos. Os resultados dessa tese permitirão a formulação de dietas experimentais e comerciais com base em nutrientes digestíveis para juvenis do robalo-flecha.

Submitted by Mario BC (mario@bc.ufrpe.br) on 2017-10-30T13:47:02Z No. of bitstreams: 1 Ricardo Luis Mendes de Oliveira.pdf: 1317636 bytes, checksum: 15cf1c9f6b999bf3bde2c6e2c177d011 (MD5) / Made available in DSpace on 2017-10-30T13:47:02Z (GMT). No. of bitstreams: 1 Ricardo Luis Mendes de Oliveira.pdf: 1317636 bytes, checksum: 15cf1c9f6b999bf3bde2c6e2c177d011 (MD5) Previous issue date: 2016-02-24 / The combined effects of feeding frequency and ration size on the growth of laboratory-reared common snook (Centropomus undecimalis) and cobia (Rachycentron canadum) juveniles were evaluated. For the first experiment (named "S") juveniles of snook with a mean weight of 2.55 g (± 0.48) and mean total length of 6.81 cm (± 0.48) were divided into groups of 20 fish and kept in 30 x 50 L experimental units for 60 days. For the cobia experiment ("C") juveniles with a weight of 2.47 g (± 0.12) and total length of 9.55 cm (± 0.18) were divided into groups of 12 fish and kept at 30 x 50 L experimental units for 28 days. In both studies the experimental design was factorial (3 x 3) with three feeding frequencies and three ration sizes, which differed between species. For the snook, 2, 4 and 6 daily meals and ration sizes of 1.0, 2.5 and 4.0% of fish biomass were tested, while for the cobia we tested 1, 3 and 6 daily meals and 3, 6 and 12% of fish biomass. An external control, using the mean food frequency of each experiment (S = 4 and C = 3) and feeding to apparent satiation, was added. There were thus ten treatments with three replicates each. The weight and length of all fish in both studies was measured to adjust the amount of feed to be administered every 15 (S) and 7 days (C). Water quality remained within acceptable levels for both species. For both species, the ration size had a larger effect on the results than feeding frequency. It is recommended to feed common snook juveniles weighing from 1 to 16 g with 4 to 6 meals a day with a ration size between 1.86 and 3.31%, while for juvenile cobia ranging from 1.6 to 38.6 g it is recommended 3 to 6 daily meals with a ration size between 6.16 and 10.51%. In both cases the ration size should decrease according to fish size. / Os efeitos da frequência e da taxa de alimentação sobre o crescimento de juvenis do robalo-flecha (Centropomus undecimalis) e do beijupirá (Rachycentron canadum) criados em laboratório foram avaliados. No primeiro experimento (denominado "R"), grupos de 20 juvenis de robalo com peso médio de 2,55 g (± 0,48) e comprimento total médio de 6,81 cm (± 0,48) foram mantidos em 30 unidades experimentais de 50 L durante 60 dias. No segundo experimento ("B"), juvenis de beijupirá com peso médio de 2,47 g (± 0,12) e comprimento total médio de 9,55 cm (± 0,18) foram divididos em grupos de 12 peixes e mantidos em 30 unidades experimentais de 50 L durante 28 dias. Em ambos estudos o delineamento experimental foi fatorial (3 x 3) com três frequências alimentares e três taxas de alimentação diárias, as quais diferiram entre as espécies. Para o robalo, foram testadas 2, 4 e 6 refeições diárias e taxas de 1,0, 2,5 e 4,0% da biomassa dos peixes, enquanto para o beijupirá testamos 1, 3 e 6 refeições diárias e 3, 6 e 12% da biomassa dos peixes. Foi adicionado um controle externo, utilizando a frequência alimentar média de cada estudo (R = 4 e B = 3) e alimentação até a saciedade aparente. Houveram, portanto, dez tratamentos com três repetições cada. Nos dois estudos foram aferidos peso e comprimento total de todos os peixes para ajuste da quantidade de ração a ser administrada a cada 15 (R) e 7 dias (B). A qualidade de água manteve-se dentro de níveis considerados aceitáveis para ambas espécies. Em ambas espécies, a taxa de alimentação teve maior influência nos resultados do que a frequência. Para juvenis de robalo com peso entre 1 a 16 g recomenda-se de quatro a seis refeições diárias com uma taxa de alimentação entre 1,86 e 3,31%/dia, enquanto que, para beijupirás com peso entre 1,6 a 38,7 g, recomenda-se o fornecimento de três a seis refeições diárias com uma taxa de alimentação entre 6,16 e 10,51%. Em ambos casos, a taxa de alimentação deve decrescer de acordo com o tamanho dos peixes.

The effect of parasitism on the individual, and on a population, is one of the least understood and poorly studied areas of fish ecology. Parasites compete for maternal energetic reserves required for the production of viable eggs and offspring; thus parasites can directly influence population dynamics by lowering the number of offspring that survive to produce. The goal of this work was to explore the effect of parasitism on the reproductive potential of fish. Traditional measures of somatic energy reserves and body condition were examined along with newer measures of fatty acids present in eggs to approximate reproductive potential. Eighty female common snook, Centropomus undecimalis, were collected during spawning season (mid April to mid October) from four spawning aggregations along the southeastern coast of Florida and examined for a suite of biological, reproductive, and parasite infection measures. General linear models were used to model somatic indices, body condition, fatty acid composition and the ratios of fatty acids in eggs as a function of parasite infection parameters, host age, capture location, capture month and year. All fish were included in the somatic indices and body condition analysis while a subset of 40 fish were used in the analysis on fatty acid composition and the ratios of fatty acids in eggs. / Includes bibliography. / Dissertation (Ph.D.)--Florida Atlantic University, 2015. / FAU Electronic Theses and Dissertations Collection

The resurgence of Texas' snook (Family Centropomidae) recreational fishery is coupled with an uncertainty as to what species occur in State waters, a limited understanding of life history, and habitat needs of its constituents. This study described species composition and early life history aspects of juvenile (< 100 mm SL) centropomids taken in bag seine collections in estuarine and freshwater habitats along the upper, middle, and lower coast of Texas during 2006 to 2010. Centropomus specimens (n = 548) captured from 41 locations across the Texas coast as well as congeners from Mexico (n = 24), Florida (n = 7), and Costa Rica (n = 3) were used in a genetics- and meristic-based determination of species composition, growth rates, range of hatching dates, geographic distribution, and habitat association. Genetic analyses of the mitochondrial DNA 16s ribosomal RNA gene and the mitochondrial control region (D - loop) validated the presence of smallscale fat snook (C. parallelus Poey, 1860, n = 333), common snook (C. undecimalis Bloch 1792, n = 212) and Mexican snook (C. poeyi Chavez, 1961, n = 3) in Texas, with the last of these validations representing the first known record of this species in Texas. AMOVA of 16s and D - loop sequences failed to detect genetic differentiation within Texas for C. parallelus and C. undecimalis. However, AMOVA for 16s and D - loop C. undecimalis sequences did yield significant genetic differences between Texas and Mexico against those from Florida and Costa Rica. Juvenile centropomids (< 100 mm SL) in Texas occupied backwater habitats with dissipated currents similar to those of Florida congeners (tidal sloughs, freshwater habitats, and structured shorelines). Coastal ranges of these species differed with C. parallelus taken from the Rio Grande to West Galveston Bay, whereas C. undecimalis was captured from the Rio Grande northward near Palacios. Three C. poeyi were captured at only two locations (Laguna Vista and Port Aransas). Daily growth rates varied between species and capture years, with these ranging from 0.22 to 0.97 mm d^-1. Analyses of hatch-date distribution suggest centropomids in Texas begin spawning in August and continue it through late September into mid-November.

In an effort to determine the optimal temperature for rearing Centropomus undecimalis larvae during the yolk resorption period, larval development was measured under four different temperature regimes (23, 25, 28 and 31 °C). The eggs were incubated at 28 °C until hatching, which occurred at about 17 hours post-fertilization. After hatching, temperatures were adjusted to the respective treatment levels. Measurements were collected from 25 individual larvae across rearing temperatures at the following pre-determined time intervals: at hatching, 24 hours post hatch (hph), 48 hph, and 72 hph. Morphometric measurements were obtained from photomicrographs, including yolk sac length and height, oil globule diameter, standard length, body height at anal pore, and eye diameter. Larvae in the 25 °C treatment had longer median standard length, body height, and more energy reserves than those larvae reared at other temperatures. The yolk sac and oil-globule were present up to 72 hph at 23 and 25°C, while these were entirely consumed after 48 hph in treatments at 28 and 31 °C. Centropomus undecimalis larvae had the highest growth rates during the first 24 hph, and this period corresponded to the highest energy consumption as determined by the decrease in yolk-sac and oil-globule volume. Survival was assessed during the third trial only. The 31 °C treatment presented the worst survival percentages, with a maximum survival of 37.2% at 24 hph, and 100% mortality at 72 hph. The 25 °C treatment featured higher survival at the end of the trial than the other treatments with 1.7% survival. Eye diameter didn't vary significantly with time and was not a useful parameter for tracking development during yolk resorption. These results led to the conclusion that 25 °C was the optimal temperature to raise snook larvae during the yolk-resorption period.

Submitted by Mario BC (mario@bc.ufrpe.br) on 2017-10-06T13:35:52Z No. of bitstreams: 1 Leilane Bruna Gomes dos Santos.pdf: 1226458 bytes, checksum: 61fd240c07e666550649b8bf8545b6e6 (MD5) / Made available in DSpace on 2017-10-06T13:35:52Z (GMT). No. of bitstreams: 1 Leilane Bruna Gomes dos Santos.pdf: 1226458 bytes, checksum: 61fd240c07e666550649b8bf8545b6e6 (MD5) Previous issue date: 2017-08-03 / The present study evaluated the gastrointestinal transit time, the anatomical characterization of the digestive tract of the cobia (Rachycentron canadum), Brazilian mojarraa (Eugerres brasilianus) and Common snook (Centropomus undecimalis) and the apparent digestibility of different ingredients by Brazilian mojarra. Eight juveniles of each species were sacrificed for anatomical characterization. Gastrointestinal transit time was evaluated in ten individuals of each species that were kept in cylindrical tanks of 300 L. The fish were fed to apparent satiety once daily with an experimental feed containing 10 g.kg -1 of oxide Of titanium. After 3 days, a second diet was offered with a similar composition but containing 10 g.kg -1 of chromium oxide. Every two hours, the feces were collected by sedimentation. The stomagomatic index was higher in the cobia (1.96 ± 0.53). On the other hand, the intestinal coefficient was higher in the Brazilian mojarra (0.57 ± 0.06). The digestive traits of the different species analyzed presented distinct anatomical and histological characteristics, probably due to their different eating habits. However, these anatomical differences had no effect on gastrointestinal transit time, which did not differ between species and was estimated at 18 h. In the digestibility experiment, six rations were prepared. The fish with 43.27g (± 12.90) and 15.40 cm (± 1.33) of weight and total length were distributed in six cylindrical-fiberglass tanks (300L; 12 fish per tank) in a system Recirculation. The dry matter (DM), crude protein (CP), ethereal extract (EE), mineral matter (MM), crude energy (CE) and amino acids (AA) coefficients were estimated. The CDA of the different nutrients of the evaluated ingredients presented values above 62.08%. The CD of the AA reflected the high digestibility of PB. The results show the capacity of the Brazilian mojarra to take advantage of both the animal and vegetable ingredients. / O presente estudo avaliou o tempo de trânsito gastrointestinal, a caracterização anatômica do trato digestivo do beijupirá (Rachycentron canadum), carapeba listrada (Eugerres brasilianus) e robalo-flecha (Centropomus undecimalis) e a digestibilidade aparente de diferentes ingredientes pela carapeba listrada. Oito juvenis de cada espécie foram sacrificados para a caracterização anatômica. O tempo de trânsito gastrointestinal foi avaliado em dez indivíduos de cada espécie que foram mantidos em tanques cilíndricos de 300 L. Os peixes foram alimentados até a saciedade aparente, uma vez por dia, com uma alimentação experimental contendo 10 g.kg-1 de óxido de titânio. Após 3 dias, foi oferecida uma segunda dieta com uma composição similar, mas contendo 10 g.kg-1 de óxido de cromo. A cada duas horas, as fezes foram coletadas por sedimentação. O índice estomagossomático foi maior no beijupirá (1,96 ± 0,53). Por outro lado, o coeficiente intestinal foi maior na carapeba (0,57 ± 0,06). Os traços digestivos das diferentes espécies analisadas apresentaram características anatômicas e histológicas distintas, provavelmente devido a seus diferentes hábitos alimentares. No entanto, essas diferenças anatômicas não tiveram efeito no tempo de trânsito gastrointestinal, que não diferiu entre as espécies e foi estimado em 18 h. No experimento de digestibilidade foram elaboradas seis rações. Os peixes com 43,27g (± 12,90) e 15,40 cm (± 1,33) de peso e comprimento total foram distribuídos em seis tanques cilíndro-cônicos de fibra de vidro (300L; 12 peixes por tanque) em sistema de recirculação. Foram estimados os coeficientes de digestibilidade aparente (CDA) de matéria seca (MS), proteína bruta (PB), extrato etéreo (EE), matéria mineral (MM), energia bruta (EB) e aminoácidos (AA). Os CDA dos diferentes nutrientes dos ingredientes avaliados, apresentaram valores acima de 62,08%. Os CDA dos aminoácidos (AA) refletiram a alta digestibilidade da PB. Os resultados encontrados evidenciam a capacidade da carapeba listrada de aproveitar tanto o ingrediente de origem animal quanto vegetal.