RESUMO

The present study investigated the best photoperiod for culturing pacu (Piaractus mesopotamicus) in recirculation aquaculture systems (RAS) based on its growth performance and hematological and oxidative stress responses. Juveniles (∼ 5 g) were subjected to five treatments (in triplicate): 24 L (light):0D (dark), 15 L: 09D, 12 L:12D, 9 L:15D, and 0 L:24D for 45 days. A total of 225 pacu individuals were randomly distributed among 15 tanks of 210 L (n = 15 per tank). Zootechnical, hematological (glucose, lactate, hematocrit, and hemoglobin), and antioxidant and oxidative stress parameters (glutathione S-transferase (GST), total antioxidant capacity against peroxyl radicals (ACAP), and lipid peroxidation (LPO) were analyzed. The zootechnical parameters (e.g., weight gain, Fulton's condition factor, and specific growth rate) were better and worse with 9 L:15D and 24 L:0D photoperiods, respectively. The hepatosomatic index was higher and lower in the 0 L:24D and 9 L:15D photoperiods. Blood lactate levels and antioxidant and oxidative stress responses were increased in the longest photoperiods (15 L:9D and 24 L:0D). In contrast, the treatments that showed lower oxidative damage (liver, gills, brain, and muscle) were 9 L:15D and 12 L:12D. In conclusion, manipulating artificial light is one way to improve fish growth and health, where the best photoperiod for pacu farming in RAS is 9 L:15D.

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We exposed adult individuals of the sentinel mangrove crab Minuca rapax to waterborne microplastics (MP; 53-63 µm polyethylene spheres) in a long-term experiment (56 days). Weassessed 1) MP effects on growth, survival, and food intake. and 2) the MP tissue acumulation and its reduction of body burden through feces and molting. MP exposure did not affect growth and survival. The hepatopancreas accumulated more MP than the gills and muscle. Most of the ingested MP particles were released in the feces and molts, indicating a rapid passage through the digestive tract. MP impaired food intake of M. rapax, with unknown consequences to the local populations. These results provide insights on MP translocation mechanisms, its elimination and toxicity associated with MP.

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RESUMO

The purpose of this study was to evaluate the effects of salinity and plant-based diet or animal-plant combination diet on the performance and metabolic status of juvenile Nile tilapia (Oreochromis niloticus). The experimental design was completely randomized in a 4 × 2 factorial scheme with four replicates. The treatments were established by the combination of salinities of 0, 10, 20, and 30 g L-1 with an animal-plant combination diet (AP) or plant-based diet (P). The replicates were 60 L tanks with 12 fish per tank. Diets were provided for 32 days, and the fish were fed three times a day (8, 12, and 17 h) until apparent satiety. Daily feed intake (DFI) was measured, body weight (BW) was recorded at the beginning and end of the trial, and total length (TL) and standard length (SL) were measured at the end of the trial. Average daily gain (ADG), specific growth rate (SGR), feed conversion ratio (FCR), and survival rate were calculated. After the biometric measurements were made at the end of the trial, blood samples were collected to determine the plasma concentrations of total protein (TP), glucose, cholesterol, and triglycerides (TG). The fish were euthanized, and the hepatopancreas was collected and weighed; thereafter, the hepatosomatic index (HSI) was calculated. An interaction was detected between salinity and diet type for final BW, ADG, TL, and SL. These traits were not influenced by salinity when it was associated with the AP diet, but reduced linearly with salinity in the P diet. DFI and survival rate were independently affected by salinity: DFI reduced linearly with salinity levels and survival rate was higher at a salinity of 10 g L-1. HSI increased linearly with salinity levels and was lower in the P diet than in the AP diet. Salinity had a quadratic effect on plasma TP, and the maximum value for this metabolite (2.96 g dL-1) is attained at a salinity of 10.26 g L-1. There was an independent effect of diet on the plasma concentrations of cholesterol and TG, which were lower in the P diet than in the AP diet. The salinity of 10 g L-1 associated with diet composed of animal and plant ingredients led to a better performance, higher survival rate, and less stressful environmental conditions for juvenile Nile tilapia.(AU)

O objetivo deste estudo foi avaliar os efeitos da salinidade e de dietas compostas por ingredientes de origem vegetal, ou por ingredientes de origem animal e vegetal no desempenho e na condição metabólica de juvenis de tilápia do Nilo (Oreochromis niloticus). O delineamento foi inteiramente casualizado em esquema fatorial 4 × 2 com quatro repetições. Os tratamentos foram estabelecidos pela combinação das salinidades 0, 10, 20 e 30 g L-1 com dietas contendo apenas ingredientes de origem vegetal (V) ou ingredientes de origem animal e vegetal (AV). As repetições foram caixas de 60 L contendo 12 peixes por caixa. As dietas foram fornecidas durante 32 dias e os peixes foram alimentados três vezes ao dia (8, 12 e 17 h) até saciedade aparente. O consumo de ração foi mensurado diariamente (CRD), o peso corporal (PC) foi registrado no início e no final do experimento, e o comprimento total (CT) e comprimento padrão (CP) foram mensurados no final do experimento. O ganho médio diário (GMD), a taxa de crescimento específico (TCE), a conversão alimentar (CA) e a taxa de sobrevivência também foram calculadas. Após a obtenção das medidas biométricas ao final do experimento, amostras de sangue foram coletadas para determinar as concentrações plasmáticas de proteínas totais (PT), glicose, colesterol e triglicerídeos (TG). Posteriormente, os peixes foram eutanasiados e o hepatopâncreas foi coletado, pesado e o índice hepatossomático (IHS) foi calculado. Houve interação entre salinidade e tipo de dieta para PC final, GMD, CT e CP. Essas variáveis não foram influenciadas pela salinidade quando associada com a dieta AV, mas reduziram linearmente com a salinidade na dieta V. O CRD e a taxa de sobrevivência foram influenciados exclusivamente pela salinidade, onde o CRD reduziu linearmente com a salinidade, e a taxa de sobrevivência foi maior na salinidade de 10 g L-1. O IHS aumentou linearmente com a salinidade, e foi menor da dieta V comparado com a dieta AV. Houve efeito quadrático da salinidade na concentração plasmática de PT, em que o máximo valor para este metabólito (2.96 g dL-1) pode ser alcançado com a salinidade de 10.26 g L-1. As concentrações plasmáticas de colesterol e TG foram exclusivamente influenciadas pelo tipo de dieta, apresentando menores valores na dieta V comparados com a dieta AV. A salinidade de 10 g L-1 associada com dieta composta por ingredientes de origem animal e vegetal proporcionou melhor desempenho, maior taxa de sobrevivência e condições ambientais menos estressantes aos juvenis de tilápia do Nilo.(AU)

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RESUMO

Wildfires are a common phenomenon in Mediterranean regions that is becoming increasingly frequent and severe, causing several environmental concerns, of which ash runoff represents an important source of disturbance for aquatic organisms, in particular for fishes. Studies on the behavioural response of fishes to wildfire ash runoff are scarce and seldom include cyprinid species. The goal of this study was to investigate in a 3-artificial flume channel mesocosm, the behavioural and hepatosomatic condition responses of a native widespread potamodromous fish, the Iberian barbel (Luciobarbus bocagei), previously exposed for 24 h to different concentrations of wildfire ashes: 0.0 g/L (the control, no ash), 1.0 g/L (low concentration) and 2.0 g/L (high concentration). Behavioural parameters included i) routine activity, ii) boldness and iii) shoaling cohesion. The hepatosomatic index (HSI) was further determined to assess the health condition of fish. Significant differences on fish behaviour parameters were detected between the control and the high concentration of ash. Accordingly, i) an increasing proportion of fish were found on resting activity (56.2% vs 30.6% in the control), whereas the proportion of fish on searching behaviour (58.4% in the control) decreased (41.5%); ii) the proportion of bolder individuals was found to decrease (42.5% in the control vs. 29.4%) and iii) the same trend was detected for shoaling cohesion (61.3% in the control to 33.8%, of all fish within a body length of each other). Such differences were paralleled by an increase in the HSI from 1.62% (control) to 2.40% (high concentration). The present study shows that even short duration exposure to ash-loaded runoff can alter fish behaviour and hepatosomatic condition and highlights the need to maintain an unfragmented river network, or, when this is not possible, to prioritize the removal or retrofitting of barriers to increase movement dispersal and provide conditions for species recovery from fire-disturbances.

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RESUMO

Brycon falcatus is one of the most highly consumed species of fish within the region in the Teles Pires basin, and has great commercial importance in sport and professional artisanal fishing. The objective of this study was to analyze the presence and concentration of total mercury (THg) in the muscle, liver and gills of B. falcatus, and calculate the risk to human health of THg contamination from ingestion of the fish. THg concentrations were similar in the liver (0.076 mg kg-1) and muscle (0.052 mg kg-1), and higher than in the gills (0.009 mg kg-1). The levels of HgT present in B. falcatus tissues did not influence weight gain and nutritional status. Based on the condition factor, weight and length ratio and hepatosomatic index, it seems that the concentrations of THg did not influence the health and well-being of B. falcatus collected in the Teles Pires River basin. THg concentrations in the muscle of B. falcatus are below the limit recommended by the World Health Organization for people who consume until 250 g of fish per week. The risk of deleterious effects on human health may exist if there is a greater consumption of B. falcatus such as 340 g/day, that is the mean of fish consumption by indigenous and riverine.(AU)

Brycon falcatus é um dos peixes mais consumidos na região da bacia do rio Teles Pires, tendo grande importância comercial na pesca esportiva e profissional artesanal. O objetivo deste estudo foi analisar a presença e concentrações de mercúrio total (HgT) no músculo, fígado e brânquias do peixe B. falcatus. Foi calculado o risco para a saúde humana de contaminação por Hg pela ingestão deste pescado. As concentrações de HgT foram similares no fígado (0,076 mg.kg-1) e no músculo (0,052 mg.kg-1) e maiores do que nas brânquias (0,009 mg.kg-1). Os níveis de HgT presentes nos tecidos de B. falcatus não influenciaram no incremento de peso e estado nutricional. Com base no fator de condição, relação peso e comprimento e índice hepatossomático, aparentemente as concentrações de THg não influenciaram a saúde e o bem-estar de B. falcatus coletados na bacia do rio Teles Pires. As concentrações de THg no músculo de B. falcatus estão abaixo do limite recomendado pela Organização Mundial de Saúde para pessoas que consomem até 250 g de peixe por semana. O risco de efeitos deletérios para a saúde humana pode existir se houver um maior consumo de B. falcatus, como 340 g/dia, que é a média do consumo de peixe por indígenas e ribeirinhos.(AU)

Assuntos

RESUMO

Brycon falcatus is one of the most highly consumed species of fish within the region in the Teles Pires basin, and has great commercial importance in sport and professional artisanal fishing. The objective of this study was to analyze the presence and concentration of total mercury (THg) in the muscle, liver and gills of B. falcatus, and calculate the risk to human health of THg contamination from ingestion of the fish. THg concentrations were similar in the liver (0.076 mg kg-1) and muscle (0.052 mg kg-1), and higher than in the gills (0.009 mg kg-1). The levels of HgT present in B. falcatus tissues did not influence weight gain and nutritional status. Based on the condition factor, weight and length ratio and hepatosomatic index, it seems that the concentrations of THg did not influence the health and well-being of B. falcatus collected in the Teles Pires River basin. THg concentrations in the muscle of B. falcatus are below the limit recommended by the World Health Organization for people who consume until 250 g of fish per week. The risk of deleterious effects on human health may exist if there is a greater consumption of B. falcatus such as 340 g/day, that is the mean of fish consumption by indigenous and riverine.(AU)

Brycon falcatus é um dos peixes mais consumidos na região da bacia do rio Teles Pires, tendo grande importância comercial na pesca esportiva e profissional artesanal. O objetivo deste estudo foi analisar a presença e concentrações de mercúrio total (HgT) no músculo, fígado e brânquias do peixe B. falcatus. Foi calculado o risco para a saúde humana de contaminação por Hg pela ingestão deste pescado. As concentrações de HgT foram similares no fígado (0,076 mg.kg-1) e no músculo (0,052 mg.kg-1) e maiores do que nas brânquias (0,009 mg.kg-1). Os níveis de HgT presentes nos tecidos de B. falcatus não influenciaram no incremento de peso e estado nutricional. Com base no fator de condição, relação peso e comprimento e índice hepatossomático, aparentemente as concentrações de THg não influenciaram a saúde e o bem-estar de B. falcatus coletados na bacia do rio Teles Pires. As concentrações de THg no músculo de B. falcatus estão abaixo do limite recomendado pela Organização Mundial de Saúde para pessoas que consomem até 250 g de peixe por semana. O risco de efeitos deletérios para a saúde humana pode existir se houver um maior consumo de B. falcatus, como 340 g/dia, que é a média do consumo de peixe por indígenas e ribeirinhos.(AU)

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RESUMO

Biomarkers are measurements within an organism that respond to environmental effects and are used as tools in bioassessment programs since they reflect physiological changes induced by exposure to pollutants. The hepatosomatic index (HSI) and the condition factor (CF) in three fish species Geophagus brasiliensis, Hypostomus affinis and Hypostomus auroguttatus were used to assess effects of pollutant stress in a tropical river during two seasons (dry and wet). Fish from the least disturbed sites had the lowest condition factor (CF) and the lowest HSI, whereas those from sites near pollutant discharges had the highest CF and HSI. Higher HSI and lower CF occurred during the dry season. It is suggested that species adapted to stressful conditions take advantage on food availability from organic loads or unoccupied niches by lesser tolerant species, increasing CF. We concluded that higher HSI values were directly associated with environmental stress whereas the higher CF values are related to availability of food resources derived from organic loads or other sources. CF and HSI are simple and cost-effective, thus suitable as routine screening tools in pollution monitoring, but caution should be taken in relating changes in physiological measurements and any specific pollutant to prevent misinterpretation.(AU)

Biomarcadores são medidas dentro de um organismo que respondem a efeitos ambientais e sãoutilizadas em programas de bioavaliação, já que refletem alterações fisiológicas induzidas pela exposição apoluentes. O índice hepatossomático (IHS) e o fator de condição (FC) das espécies Geophagus brasiliensis,Hypostomus affinis e Hypostomus auroguttatus foram calculados em um rio tropical durante duas estações (secae cheia). Peixes de locais menos alterados apresentaram menores FC e IHS, enquanto os de locais próximosde descargas de poluentes apresentaram maiores FC e IHS. Maiores IHS e menores FC ocorreram durantea estação seca, comparados com a estação chuvosa. É sugerido que espécies adaptadas às condiçõesestressantes levam vantagem da disponibilidade de alimentos próxima às descargas orgânicas ou nichos nãoocupados por espécies menos tolerantes, aumentado o FC. Os valores mais elevados do IHS foramdiretamente associados ao estresse ambiental, enquanto os valores mais elevados FC estão relacionados coma disponibilidade de recursos alimentares derivados de descargas orgânicas ou outras fontes. FC e IHS sãosimples e de baixo custo, portanto, adequados como ferramentas no controle da poluição, mas cuidadosdevem ser tomados ao relacionar suas mudanças às medições fisiológicas ou a qualquer poluente específicopara evitar efeitos de interferência.(AU)

Assuntos

RESUMO

Biomarkers are measurements within an organism that respond to environmental effects and are used as tools in bioassessment programs since they reflect physiological changes induced by exposure to pollutants. The hepatosomatic index (HSI) and the condition factor (CF) in three fish species Geophagus brasiliensis, Hypostomus affinis and Hypostomus auroguttatus were used to assess effects of pollutant stress in a tropical river during two seasons (dry and wet). Fish from the least disturbed sites had the lowest condition factor (CF) and the lowest HSI, whereas those from sites near pollutant discharges had the highest CF and HSI. Higher HSI and lower CF occurred during the dry season. It is suggested that species adapted to stressful conditions take advantage on food availability from organic loads or unoccupied niches by lesser tolerant species, increasing CF. We concluded that higher HSI values were directly associated with environmental stress whereas the higher CF values are related to availability of food resources derived from organic loads or other sources. CF and HSI are simple and cost-effective, thus suitable as routine screening tools in pollution monitoring, but caution should be taken in relating changes in physiological measurements and any specific pollutant to prevent misinterpretation.

Biomarcadores são medidas dentro de um organismo que respondem a efeitos ambientais e são utilizadas em programas de bioavaliação, já que refletem alterações fisiológicas induzidas pela exposição a poluentes. O índice hepatossomático (IHS) e o fator de condição (FC) das espécies Geophagus brasiliensis, Hypostomus affinis e Hypostomus auroguttatus foram calculados em um rio tropical durante duas estações (seca e cheia). Peixes de locais menos alterados apresentaram menores FC e IHS, enquanto os de locais próximos de descargas de poluentes apresentaram maiores FC e IHS. Maiores IHS e menores FC ocorreram durante a estação seca, comparados com a estação chuvosa. É sugerido que espécies adaptadas às condições estressantes levam vantagem da disponibilidade de alimentos próxima às descargas orgânicas ou nichos não ocupados por espécies menos tolerantes, aumentado o FC. Os valores mais elevados do IHS foram diretamente associados ao estresse ambiental, enquanto os valores mais elevados FC estão relacionados com a disponibilidade de recursos alimentares derivados de descargas orgânicas ou outras fontes. FC e IHS são simples e de baixo custo, portanto, adequados como ferramentas no controle da poluição, mas cuidados devem ser tomados ao relacionar suas mudanças às medições fisiológicas ou a qualquer poluente específico para evitar efeitos de interferência.

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RESUMO

The objective of this study was to analyze population structure (spatial distribution, seasonal distribution and distribution by length classes, sex ratio and length-weight relationship) and aspects of the reproductive biology of Loricariichthys melanocheilus. Fish were sampled bimonthly using gillnets and trammel nets in lentic and lotic environments in the rio Ibicuí, between the years 2000 and 2001. Were collected 410 specimens: 230 females, 164 males and 16 specimens whose sex could not be determined. A greater number of specimens were collected in October/November and December/January and in lentic environments. The greater length classes had a higher amount of females (p < 0.05) and the sex ratio in all sampling periods was 1.38 females per male. Both males and females showed positive allometric growth (b = 3.299 and b =3.487, respectively). The highest values for gonadosomatic index (GSI) and gonadal condition factor (K) were observed from August/September and peaked in October/November, just like the highest frequencies of females at maturity stage C (mature), which is indicative that the breeding season occurs at this time.

O objetivo deste trabalho foi analisar a estrutura populacional (distribuição espacial, sazonal e por classes de comprimento, proporção sexual e relação peso-comprimento) e aspectos da biologia reprodutiva de Loricariichthys melanocheilus. Os peixes foram amostrados bimestralmente com redes de espera e feiticeiras em ambientes lêntico e lóticos no rio Ibicuí, entre os anos de 2000 e 2001. Foram capturados 410 indivíduos: 230 fêmeas, 164 machos e 16 indivíduos que não foi possível determinar o sexo. Foi capturado um maior número de indivíduos em outubro/novembro e dezembro/janeiro e em ambientes lênticos. As classes de comprimento superiores apresentaram maior quantidade de fêmeas (p < 0.05) e a proporção sexual em todos os períodos amostrados foi de 1,38 fêmeas para cada macho. Tanto os machos quanto as fêmeas apresentaram crescimento alométrico positivo (b = 3.299 and b =3.487, respectivamente). Os maiores valores do Índice Gonadossomático (IGS) e do fator de condição gonadal (K) foram observados a partir de agosto/setembro, com pico em outubro/novembro, assim com as maiores frequências de fêmeas em estádio de maturação C (maduro), indicando que o período reprodutivo se dá nesta época.

Assuntos

RESUMO

The objective of this study was to analyze population structure (spatial distribution, seasonal distribution and distribution by length classes, sex ratio and length-weight relationship) and aspects of the reproductive biology of Loricariichthys melanocheilus. Fish were sampled bimonthly using gillnets and trammel nets in lentic and lotic environments in the rio Ibicuí, between the years 2000 and 2001. Were collected 410 specimens: 230 females, 164 males and 16 specimens whose sex could not be determined. A greater number of specimens were collected in October/November and December/January and in lentic environments. The greater length classes had a higher amount of females (p < 0.05) and the sex ratio in all sampling periods was 1.38 females per male. Both males and females showed positive allometric growth (b = 3.299 and b =3.487, respectively). The highest values for gonadosomatic index (GSI) and gonadal condition factor (K) were observed from August/September and peaked in October/November, just like the highest frequencies of females at maturity stage C (mature), which is indicative that the breeding season occurs at this time.(AU)

O objetivo deste trabalho foi analisar a estrutura populacional (distribuição espacial, sazonal e por classes de comprimento, proporção sexual e relação peso-comprimento) e aspectos da biologia reprodutiva de Loricariichthys melanocheilus. Os peixes foram amostrados bimestralmente com redes de espera e feiticeiras em ambientes lêntico e lóticos no rio Ibicuí, entre os anos de 2000 e 2001. Foram capturados 410 indivíduos: 230 fêmeas, 164 machos e 16 indivíduos que não foi possível determinar o sexo. Foi capturado um maior número de indivíduos em outubro/novembro e dezembro/janeiro e em ambientes lênticos. As classes de comprimento superiores apresentaram maior quantidade de fêmeas (p < 0.05) e a proporção sexual em todos os períodos amostrados foi de 1,38 fêmeas para cada macho. Tanto os machos quanto as fêmeas apresentaram crescimento alométrico positivo (b = 3.299 and b =3.487, respectivamente). Os maiores valores do Índice Gonadossomático (IGS) e do fator de condição gonadal (K) foram observados a partir de agosto/setembro, com pico em outubro/novembro, assim com as maiores frequências de fêmeas em estádio de maturação C (maduro), indicando que o período reprodutivo se dá nesta época.(AU)

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RESUMO

Previously recognized color and pattern variants of adult Cichla temensis in Amazon flood pulse river environments reflect the cycling of individuals through seasonal sexual maturity and spawning. Individuals also vary in shape from blocky to fusiform. To determine if shape differences are related to patterns of fat reserve deposition and utilization, and to quantify the relationship of shape with color and pattern variation and life history status, specimens in each of four previously defined grades of color and pattern variation were compared using geometric morphometric techniques. Progressive shape changes occurred between grades independent of sex and correlated to gonosomatic index (GSI). Thin plate spline deformation visualizations indicate that the observed shape differences are related to fat deposition patterns. The seasonal timing of shape change and its link to color pattern variation, sexual maturity and local water level conditions suggests a relationship between the physiological and behavioral characteristics of C. temensis and the cyclical flood pulse pattern of its habitat.

As variantes de cor e padrão previamente reconhecidos dos adultos de Cichla temensis em ambientes alagáveis amazônicos refletem o ciclo de indivíduos durante o período de maturidade sexual e desova. Indivíduos também variam na forma de oblonga a fusiforme. Para determinar se as diferenças de forma estão relacionadas aos padrões de deposição e utilização das reservas de gordura e quantificar a relação da forma com cor, variação de padrão e status da história de vida, espécimes de cada quatro níveis de cor e variação de padrão previamente definidos foram comparados usando técnicas de morfometria geométrica. Mudanças progressivas ocorreram na forma entre os níveis independentes do sexo e correlacionadas ao índice gonadossomático (IGS). Visualizações de finas deformações na placa da espinha indicam que as diferentes formas observadas estão relacionadas aos padrões de deposição de gordura. O período de mudança de forma e sua ligação com a variação do padrão de cor, maturidade sexual e as condições do nível da água local sugerem uma relação entre as características fisiológicas e comportamentais de Cichla temensis e o padrão de inundação cíclico do seu habitat.

Assuntos

RESUMO

Previously recognized color and pattern variants of adult Cichla temensis in Amazon flood pulse river environments reflect the cycling of individuals through seasonal sexual maturity and spawning. Individuals also vary in shape from blocky to fusiform. To determine if shape differences are related to patterns of fat reserve deposition and utilization, and to quantify the relationship of shape with color and pattern variation and life history status, specimens in each of four previously defined grades of color and pattern variation were compared using geometric morphometric techniques. Progressive shape changes occurred between grades independent of sex and correlated to gonosomatic index (GSI). Thin plate spline deformation visualizations indicate that the observed shape differences are related to fat deposition patterns. The seasonal timing of shape change and its link to color pattern variation, sexual maturity and local water level conditions suggests a relationship between the physiological and behavioral characteristics of C. temensis and the cyclical flood pulse pattern of its habitat.(AU)

As variantes de cor e padrão previamente reconhecidos dos adultos de Cichla temensis em ambientes alagáveis amazônicos refletem o ciclo de indivíduos durante o período de maturidade sexual e desova. Indivíduos também variam na forma de oblonga a fusiforme. Para determinar se as diferenças de forma estão relacionadas aos padrões de deposição e utilização das reservas de gordura e quantificar a relação da forma com cor, variação de padrão e status da história de vida, espécimes de cada quatro níveis de cor e variação de padrão previamente definidos foram comparados usando técnicas de morfometria geométrica. Mudanças progressivas ocorreram na forma entre os níveis independentes do sexo e correlacionadas ao índice gonadossomático (IGS). Visualizações de finas deformações na placa da espinha indicam que as diferentes formas observadas estão relacionadas aos padrões de deposição de gordura. O período de mudança de forma e sua ligação com a variação do padrão de cor, maturidade sexual e as condições do nível da água local sugerem uma relação entre as características fisiológicas e comportamentais de Cichla temensis e o padrão de inundação cíclico do seu habitat.(AU)

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RESUMO

The reproductive biology of Mugil liza Valenciennes, 1836 is described as a contribution to an elaborate management programm. A total of 243 specimens (89 males and 154 females) were collected in the Sepetiba Bay in south-eastern Brazil from July/2006 to June/2007. The gonadosomatic index (I G) and the sequential development of the ovaries observed through histological studies suggested that the spawning season ranged from May to August. The population reached total sexual maturity (L T100) at 550 and 570 mm total length (L T) for males and females, respectively. Females attained a larger size than males, and the sex ratio was female-biased for fish larger than 500 mm L T. The hepatosomatic index (I H) was significantly related to the I G, indicating that vitellogenesis mobilizes hepatic energy during reproduction. Mean fecundity was 3,080,000 oocytes. The presence of only two phases of oocyte development in ripe ovaries - a reserve stock and a clutch of post-vitellogenic oocytes - indicated that ovarian development is group synchronic and this species is characterized as a total spawner. The results suggest that establishing a closed fishing season from May to August and establishing a minimum size for capture of 350 mm L T would enhance stock conservation and production for future harvest seasons.

RESUMO

The reproductive biology of Mugil liza Valenciennes, 1836 is described as a contribution to an elaborate management programm. A total of 243 specimens (89 males and 154 females) were collected in the Sepetiba Bay in south-eastern Brazil from July/2006 to June/2007. The gonadosomatic index (I G) and the sequential development of the ovaries observed through histological studies suggested that the spawning season ranged from May to August. The population reached total sexual maturity (L T100) at 550 and 570 mm total length (L T) for males and females, respectively. Females attained a larger size than males, and the sex ratio was female-biased for fish larger than 500 mm L T. The hepatosomatic index (I H) was significantly related to the I G, indicating that vitellogenesis mobilizes hepatic energy during reproduction. Mean fecundity was 3,080,000 oocytes. The presence of only two phases of oocyte development in ripe ovaries - a reserve stock and a clutch of post-vitellogenic oocytes - indicated that ovarian development is group synchronic and this species is characterized as a total spawner. The results suggest that establishing a closed fishing season from May to August and establishing a minimum size for capture of 350 mm L T would enhance stock conservation and production for future harvest seasons.

RESUMO

The reproductive biology of Mugil liza Valenciennes, 1836 is described as a contribution to an elaborate management programm. A total of 243 specimens (89 males and 154 females) were collected in the Sepetiba Bay in south-eastern Brazil from July/2006 to June/2007. The gonadosomatic index (I G) and the sequential development of the ovaries observed through histological studies suggested that the spawning season ranged from May to August. The population reached total sexual maturity (L T100) at 550 and 570 mm total length (L T) for males and females, respectively. Females attained a larger size than males, and the sex ratio was female-biased for fish larger than 500 mm L T. The hepatosomatic index (I H) was significantly related to the I G, indicating that vitellogenesis mobilizes hepatic energy during reproduction. Mean fecundity was 3,080,000 oocytes. The presence of only two phases of oocyte development in ripe ovaries - a reserve stock and a clutch of post-vitellogenic oocytes - indicated that ovarian development is group synchronic and this species is characterized as a total spawner. The results suggest that establishing a closed fishing season from May to August and establishing a minimum size for capture of 350 mm L T would enhance stock conservation and production for future harvest seasons.

RESUMO

A reproductive analysis of 1 225 specimens of Poeciliopsis gracilis obtained through monthly samples from Coatetelco, a tropical shallow lake in Central Mexico, was made. There was an evident sexual dimorphism, including a difference in body size at the onset of reproduction. Sex ratio deviated significantly from unity. Monthly variations in gonadosomatic (GSI), hepatosomatic (HSI) indexes and ovarian development stages showed that the spawning season was from July to October, coinciding with the rainy season and phytoplankton biomass increase. The largest sizes were 50 mm for females and 43 mm for males. Rev. Biol. Trop. 56 (4): 1801-1812. Epub 2008 December 12.

Se realizó el análisis reproductivo de 1 225 organismos de Poeciliopsis gracilis que se obtuvieron de manera mensual en el lago Coatetelco, un cuerpo somero tropical en México. Se hizo evidente un dimorfismo sexual en las características morfológicas de esta especie. Se observó una diferencia en el tamaño corporal entre los sexos al inicio de la reproducción. La proporción sexual fue diferente de uno. Con base en la variación mensual del índice gonadosomático (IGS), hepatosomático (IHS) y los estadios de madurez gonádica, se observó que la época de reproducción de P. gracilis se realiza entre julio y octubre, que coincide con la época de lluvias e incremento de la biomasa del fitoplancton. La talla más grande registrada fue de 50 mm para las hembras y de 43 mm para los machos.

Assuntos