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Condition indices are key predictors of health and fitness in wild fish populations. Variation in body condition, therefore, can be used to identify stressful conditions that may impact endangered species, such as California’s endemic Delta Smelt (Hypomesus transpacificus McAllister, 1963). Here, we examined spatiotemporal variation in the condition indices of > 1600 Delta Smelt collected over nine years (2011–2019), a period characterized by tremendous variability in hydrodynamic and water quality conditions. The population exhibited low hepatosomatic index (HSI) and condition factor (CF) during September/October/November (fall), and both condition indices declined over the nine-year study during fall. HSI was positively correlated with indicators of pelagic productivity (e.g., Chlorophyll a, zooplankton biomass, and proximity to tidal wetlands), whereas CF was negatively correlated with temperature, peaking at a relatively cool 10–13°C. In sum, seasonal and interannual variation in body condition corresponded most strongly with pelagic productivity and water temperature, with little correlation to freshwater outflow. Management actions that increase pelagic productivity, restore and freshen productive wetlands during late summer-fall, and reduce water temperatures overall are likely to benefit condition indices and, therefore, fitness of the Delta Smelt population.

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. 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.

The length-weight relationship, condition factor, fecundity, gonadosomatic and hepatosomatic indices of Parachanna obscura from the Anambra River were determined between December 2015 and June 2016. Eighty-three live samples of P. obscura were obtained from fishermen. Descriptive statistics, correlation and regression analysis were used to analyze the obtained data. The length-weight relationship had R values of 0.933, 0.843 and 0.896 for male, female and combined sexes, respectively. The b value of 3.133 for male and 2.674 for female were not significantly different (P>0.05). Mean condition factors of 0.89±0.33 and 0.80±0.21 were obtained for female and male, respectively. The largest number of eggs (10,965) was found in a female with the body weight of 154 g, gonad weight of 9.1 g and egg size of 1.3 mm, while the least fecund female with 1820 eggs weighed (94 g) and had a gonad weight 2.1 g with egg size of 1.0 mm. The hepatosomatic indices ranged between 0.55±0.20 and 0.64±0.29 in both male and female, respectively, while female gonadosomatic index average was 2.05±1.44. There was a positive correlation between fecundity and gonad weight.

Curcumin exhibited numerous key activities including antioxidant, anti-inflammatory, and immunostimulatory effects in fish. This study evaluated the protective effects of curcumin (CUR) against lead (Pb)-induced toxicities in fish. Healthy Cyprinus carpio L. individuals were segregated into control, Pb only, Pb+CUR, and CUR only groups. Pb groups were exposed to 1 mg L −1 of Pb, and CUR groups were fed a basal diet supplemented with 15 g kg−1 of CUR. After eight weeks, growth performance, Pb accumulation in tissues, various haemato-biochemical parameters, immune responses, and cytokine gene expression were measured. Dietary CUR effectively decreased Pb accumulation in tissues and increased the survival of Pb-exposed fish. Co-treatment with Pb and CUR reversed alterations in haemato-biochemical parameters, ameliorated Pb-induced oxidative stress, enhanced immune responses, and restored intestinal enzymatic activities. Dietary CUR reversed changes in intestinal microbiota in Pb-exposed fish. Pb-induced upregulation of NF-κBp65 and HSP70 was inhibited by dietary CUR. CUR supplementation upregulated the mRNA levels of SOD, Nrf2, IL-10, and CYP450 1A and attenuated Pb-induced degradation of I κB-α mRNA levels. Overall, CUR antagonizes Pb-induced negative impacts in fish. Thus, dietary CUR had several beneficial effects on immune responses, decreased Pb accumulation in tissues, and reversed Pb-induced oxidative stress in fish. Therefore, CUR plays a protective role in Pb-induced immune toxicity in fish, and, as such, may be suitable as an aqua feed additive for use in carp aquaculture.

This study aims to determine various relationships between liver, gonad and body weights of the two pipefish species caught in two breeding seasons from the Bafa Lake (Muğla) coasts between 2014 -2016. Using beach seine-net in the lake, a total of 208 pipefish specimens (79 Synathus abaster and 129 Synathus acus) were sampled. L-W relationship and Fulton condition factor were W = 2E - 0.94.01, 0.035 ± 0.009 in S.abaster specimens. Also LW relationships and condition factor were W = 8E-0.93.83 , 0.033 ± 0.01 in S. acus. On the other hand mean ± SD of HSI and GSI values were 2.18 ± 1.65 and 7.69 ± 7.12 respectively. In S.acus values 3.22 ± 3.13 and 5.49 ± 5.12 as well. The decrease in HIS and K values, provides sufficient information to claim that species in the lake spend all energy requirement obtained with proper feeding to growth and gonad development.

Simple Summary A tiny fraction of all introduced species worldwide successfully establishes viable populations that rapidly spread and negatively impact native biodiversity and ecosystem functioning—i.e., become invasive. Even so, invasive species exert adverse environmental, economic, and human health impacts globally. Thus, identification of successful invaders is one of the immediate challenges in invasion biology. Recent studies highlight species’ immunity as an important component of invasion success since it enables invaders to adapt to the novel conditions as they expand their range. Here, we analyzed whether the immune response of the successful crayfish invader, the signal crayfish, changes as the invader encounters different environmental conditions and novel counterparts. We used several parameters, frequently applied to assess crayfish immunological status, and compared their cumulative pattern between sites along the signal crayfish invasion range in the Korana River, Croatia, as well as between the invasive signal crayfish and the native narrow-clawed crayfish. Immune response differed between native and invasive species and exhibited variations along the invasion range, which were mostly affected by water temperature and crayfish density. Our results indicate that changes in immunity may occur during range expansion, and imply that immunity could have a role in invasion success of invertebrate invaders. Abstract Immunity is an important component of invasion success since it enables invaders’ adaptation to conditions of the novel environment as they expand their range. Immune response of invaders may vary along the invasion range due to encountered parasites/microbial communities, conditions of the local environment, and ecological processes that arise during the range expansion. Here, we analyzed changes in the immune response along the invasion range of one of the most successful aquatic invaders, the signal crayfish, in the recently invaded Korana River, Croatia. We used several standard immune parameters (encapsulation response, hemocyte count, phenoloxidaze activity, and total prophenoloxidaze) to: i) compare immune response of the signal crayfish along its invasion range, and between species (comparison with co-occurring native narrow-clawed crayfish), and ii) analyze effects of specific predictors (water temperature, crayfish abundance, and body condition) on crayfish immune response changes. Immune response displayed species-specificity, differed significantly along the signal crayfish invasion range, and was mostly affected by water temperature and population abundance. Specific immune parameters showed density-dependent variation corresponding to increased investment in them during range expansion. Obtained results offer baseline insights for elucidating the role of immunocompetence in the invasion success of an invertebrate freshwater invader.

Parasite distribution among hosts is a fundamental aspect of host–parasite interactions. Aggregated parasite distributions within and across host species are commonly reported and potentially influenced by many factors, whether host or parasite specific, or related to host–parasite encounter and compatibility. Yet, the respective role of each in observed parasite distributions are often unclear. Here, we documented the distribution of the acanthocephalan parasitePomphorhynchus laevis sensu lato(s.l.) in two replicate fish host populations. Aggregated distributions were observed in both populations, within and across fish host species. We found a positive abundance–prevalence relationship across fish species, suggesting that resource availability (fish host biomass density) was the main driver ofP. laevis s.l.distribution. This was supported by further positive associations between mean parasite load and fish biomass density. We found little evidence for intensity-dependent regulation within host (i.e. intra-host competition among co-infecting parasites). Furthermore,P. laevis s.l.infection had no detectable effect on fish condition indices, except on the body condition of female barbel (Barbus barbus). Therefore,P. laevis s.l.tended to accumulate with size/age within fish species, and with fish biomass density among fish species, with apparently negligible limitations due to intra-host intensity-dependent regulation of parasite, or to parasite-induced morbidity in fish. The relative availability of final hosts for trophic transmission thus appears to be the main driver ofP. laevis s.l.distribution among fish.

The objective of this work was to evaluate different feeding rates on the productive performance of cobia (Rachycentron canadum) grown in brackish waters. For the experiment, 1,600 juveniles were distributed in 16 enclosures installed in an estuarine pond. Four different feeding rates were evaluated: 1, 3, 5, and 7% live weight (LW) per day. The following performance parameters were assessed: survival, final biomass, specific growth rate, daily weight gain, apparent feed conversion, protein efficiency rate, lipid efficiency rate, and hepatosomatic index. Survival was greater than 80% at all feeding rates. The most efficient feed conversion rate was obtained with the feeding rate of 5% LW per day, which also resulted in better values for the hepatosomatic index. The rate of 5% LW per day provides a better productive performance for cobia in brackish waters. Resumo: O objetivo deste trabalho foi avaliar diferentes taxas de arraçoamento no desempenho produtivo de bijupirá (Rachycentron canadum) criado em águas salobras. Para o experimento, 1.600 juvenis foram distribuídos em 16 cercados instalados em viveiro, em área estuarina. Foram avaliados quatro diferentes níveis de arraçoamento: 1, 3, 5 e 7% do peso vivo (PV) por dia. Avaliaram-se os seguintes parâmetros de desempenho: sobrevivência, biomassa final, taxa de crescimento específico, ganho de peso diário, conversão alimentar aparente, taxa de eficiência proteica, taxa de eficiência lipídica e índice hepatossomático. A sobrevivência foi superior a 80% em todos os níveis de arraçoamento. A conversão alimentar aparente mais eficiente foi obtida com a taxa de arraçoamento de 5% do PV por dia, que também resultou em melhores valores para o índice hepatossomático. A taxa de 5% do PV por dia proporciona melhor desempenho produtivo para o bijupirá em águas salobras.

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. RESUMO 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.

13 pages, 7 figures, 2 tables, supplementary information https://doi.org/10.1111/fog.12237, Depth and seasonal trends in the biological condition and recruitment of the red shrimp (Aristeus antennatus) have been analyzed over the slope to 2,233 m in the western Mediterranean. The best biological condition of A. antennatus (gonadosomatic index [GSI]) for mating and spawning occurred at 800–1,300 m in summer, in areas deeper than the fishing grounds distributed between 500 and 800 m. Females moved shallower to feed on the upper slope during periods of water‐mass homogeneity (autumn–winter), increasing their hepatic gland weight (hepatosomatic index [HSI]). Females moved downslope (800–1,100 m) to spawn (high GSI) during periods of water mass stratification (late spring–summer). The HSI of females decreased with depth down the slope in autumn, after the reproductive period. Small juveniles were distributed deeper than 1,000 m, associated with high near‐bottom O2 levels, low turbidity and high C:N in sediments, implying favorable trophic conditions. This confirms the importance in studying the biology of deep‐sea species over their entire depth range. The progressive warming and increasing salinity of deep Mediterranean waters could provoke a decrease of dissolved O2 that would affect the life cycle of A. antennatus, This study was financed within the framework of the MICYT (Ministries of Science, Spain) projects BIOMARE (CTM2006-13508-CO2-02/MAR) and ANTROMARE (CTM2009-12214-C02-01-MAR), and it was also possible thanks to the multi-methological design work contained in proposals like TRENDSEAS (CTM2014-54018-C3

Background Global trend of the introduction of high levels of relatively cheap carbohydrates to reduce the amount of costly protein in the aquatic animal feed production has affected the aquaculture of an economically important cyprinid fish, blunt snout bream (Megalobrama amblycephala). This dietary shift has resulted in increased prevalence of metabolic disorders, often causing economic losses. High dietary intake of carbohydrates, associated with obesity, is one of the major causes of non-alcoholic fatty liver disease (NAFLD) in humans. Results We have conducted an eight-week feeding trial to better understand how a high-carbohydrate diet (HCBD) affects the liver health in this fish. Hepatosomatic index and lipid content were significantly (P

O objetivo deste trabalho foi avaliar o efeito de fotoperíodo nos níveis plasmáticos do hormônio luteinizante (LH) e na maturação gonadal de fêmeas de lambari. Cento e vinte lambaris adultos, distribuídos em 12 aquários de 20 L cada um, em delineamento inteiramente casualizado, foram submetidos a três tratamentos e quatro repetições. Os tratamentos foram fotoperíodos, em horas de luz (L) e escuro (E): T1, 0 L:24 E; T2, 12 L:12 E; T3, 24 L:0 E. Após 40 dias, os peixes foram mantidos em jejum de 24 horas e, em seguida, foram anestesiados. Imediatamente após o abate, os peixes foram pesados, e suas gônadas e fígados foram retirados e pesados. Os ovários foram pesados e imersos em solução fixadora de Bouin por 24 horas e, em seguida, foram mantidos em álcool 70% até o processamento do material. Subsequentemente, o estágio de desenvolvimento dos ovócitos foi determinado. Não foram observadas diferenças significativas entre os tratamentos, quanto a peso final, peso da gônada, índice gonadossomático (IGS), índice hepatossomático (IHS) e níveis de LH. Em todos os tratamentos, as fêmeas de lambari apresentaram ovários em maturação com a prevalência de ovócitos vitelogênicos. O fotoperíodo não influencia os níveis de LH e a maturação ovariana em fêmeas de lambari. The objective of this work was to evaluate the effect of photoperiod on luteinizing hormone (LH) plasma levels and gonadal maturation of lambari females. One hundred and twenty adult lambaris, distributed into 12 aquaria of 20 L each, were randomly subjected to three different treatments, in a completely randomized design, and four replicates. Treatments were photoperiods in hours of light (L) and darkness (D): T1, 0 L:24 D; T2, 12 L:12 D; T3, 24 L:0 D. After 40 days, fish were subjected to fasting for 24 hours and, then, anesthetized. Immediately after slaughter, fish were weighed, and their gonads and livers were removed and weighed. Ovaries were weighed and immersed in Bouin's fixative solution for 24 hours and, then, kept in 70% alcohol until processing the material. Subsequently, the oocyte developmental stage was determined. No significant differences were observed between treatments for final weight, ovary weight, gonadosomatic index (GSI), hepatosomatic index (HSI) and LH levels. In all treatments, lambari females showed maturing ovaries with prevalence of vitellogenic oocytes. Photoperiod does not affect the LH levels and ovarian maturation in lambari females.

Weight–lengthrelationships,weightconversionfactorsandsomaticindicesarepresentedfromadecade (2006 to 2015) for two stocks of Lophius budegassa and L.piscatorius in northern Iberian Atlantic waters (ICES Div. VIIIc–IXa2) and in Celtic Sea, south-western Ireland and Porcupine Bank (Div. VIIb,c,h,j,k). A total of 3298 L.budegassa and 7219 L.piscatorius were sampled from commercial landings and research surveys. Total length (Lt), total weight (Wt), ‘‘commercial’’ weight (Wgl) and ‘‘scientific’’ weight (Wg) were obtained. The parameters (a, b) in the power relationships weight–length for combined sexes in L.budegassa were: 0.020, 2.916; 0.017, 2.929; 0.017, 2.922 for Wt, Wgl and Wg respectively in Div. VIIIc–IXa2;0.025,2.841;0.013,2.984;0.013,2.971inDiv.VIIb,c,h,j,k.ForL.piscatorius:0.025,2.853;0.020, 2.868;0.024,2.861inDiv.VIIIc–IXa2;0.027,2.826;0.023,2.825;0.023,2.816inDiv.VIIb,c,h,j,k.Significant differences between stocks were found in both species. The conversion factors between total and gutted weight in L.budegassa were: 1.186, 1.236 for Wgl and Wg respectively in Div. VIIIc–IXa2; 1.187, 1.233 in Div. VIIb,c,h,j,k. For L.piscatorius: 1.181, 1.241 in Div. VIIIc–IXa2; 1.210, 1.262 in Div. VIIb,c,h,j,k. The parameters can be used in the process of annual assessment of the state of each stock. Gonadosomatic index (GSI), hepatosomatic index (HSI) and Le Cren’s condition factor, indicators of reproductive and nutritional status, were seasonally analyzed and compared between sexes and stocks. Significant better condition and higher GSI and HSI were found in females. In Div. VIIb,c,h,j,k better condition was found for both species and higher GSI for L.piscatorius. The analysis throughout the year of GSI and HSI for L.budegassashowedseasonalityinlivergrowthprevioustospawnandcorroboratedthespawningseason from January to June in VIIIc–IXa2. The parameters obtained were compared with previous ones from these and others Lophiiformes, showing common patterns., SI

In this study, we analysed the variability of reserve storage in juvenile European hake (Merluccius merluccius) off the western coasts of Italy (Central Mediterranean Sea). Reserve storage was measured by the hepatosomatic index (HSI), in relation to environmental and population covariates. HSI has been proved to be a consistent measure of energy storage in gadoids, thus reflecting quantity and quality of food availability for growth. Generalized Additive Models for Location, Scale and Shape (GAMLSS) were used to model the effect of depth, bottom temperature, bottom currents, fish density and fish body size on HSI of juvenile European hake. The results revealed that reserve storage in the liver appears to be maximized for juveniles living on the shelf break, between 120 and 170 m depth, with bottom temperature and current speed not exceeding 14 °C and 0.04 m s−1 respectively. Furthermore, HSI significantly increased with fish density up to about 6000 individuals per km−2 and decreased at higher densities indicating that reserve accumulation in the liver might be subject to density-dependent mechanisms (e.g. competition for food) as well. These findings suggest that the use of density as measure of nursery importance need to be further investigated. Finally, we found that HSI increased with fish size up to about 14 cm total length. Based on these results, HSI appears a reasonable index to indirectly measure the quality of habitats where juvenile European hake aggregate after their settlement on the bottom, and to potentially monitor habitat suitability as nursery across the spatial-temporal gradient.

Three experiments were conducted with juveniles of the crayfish Cherax quadricarinatus to investigate the effect of intermittent feeding regimes on growth and the ability to tolerate the shortage of food. In experiment 1, stage III juveniles were assigned to one of seven intermittent feeding groups (from FS1: 1. day fed/1. day non-fed to FS7: 7. days fed/7. days non-fed) and two control groups, continuously fed (CF) and continuously starved (CS) animals; this experiment comprised a short-term intermittent feeding period until the first molt, followed by a continuous feeding period. In the experiment 2, stage III juveniles were assigned to one of three intermittent feeding groups (FS2 to FS4) and one control group (CF); it consisted of a prolonged intermittent feeding period, until the end of the experiment. In the experiment 3, stage VI and VII juveniles were assigned to one of three intermittent feeding groups (FS2 to FS4) and one control (CF); it also consisted of a prolonged intermittent feeding period. The red claw crayfish juveniles were able to tolerate periods of intermittent feeding and underwent compensatory growth after continuous feed was re-established. The ability of crayfish to tolerate intermittent feeding was influenced by developmental stage and duration of the intermittent feeding period. Stage III juveniles survived, but decreased growth, when subjected to prolonged intermittent feeding. However, they showed full compensatory growth when the intermittent feeding period was short and followed by continuous feeding. On the other hand, stage VI-VII tolerated 60. days of prolonged intermittent feeding without any change in growth and survival. The hepatosomatic index (based on wet weight) values of the treatments and the control were similar, suggesting that intermittent feeding may not be considered a nutritional stress condition. The relative pleon weight (based on wet weight) values of the treatments and control were similar suggesting low use of nutrients from the muscle to increase the chance for survival. The juveniles of C. quadricarinatus can tolerate relatively long periods of low food availability and this is an important adaptation for their survival in changing/unpredictable environments and an attribute favorable for the production of the species. © 2011 Elsevier B.V. Fil: Stumpf, Liane. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Biodiversidad y Biología Experimental. Laboratorio de Biología de la Reproducción y Crecimiento de Crustáceos Decápodos; Argentina Fil: Calvo, Natalia Soledad. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Biodiversidad y Biología Experimental. Laboratorio de Biología de la Reproducción y Crecimiento de Crustáceos Decápodos; Argentina Fil: Castillo Díaz, Fernando. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Biodiversidad y Biología Experimental. Laboratorio de Biología de la Reproducción y Crecimiento de Crustáceos Decápodos; Argentina Fil: Valenti, Wagner C.. Universidade de Sao Paulo; Brasil Fil: Lopez, Laura Susana. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Biodiversidad y Biología Experimental. Laboratorio de Biología de la Reproducción y Crecimiento de Crustáceos Decápodos; Argentina

Seven demersal shark species belonging to six families, obtained from the southern Mediterranean Sea, were selected as representative of different putative swimming modes, inhabited depths and trophic levels. Caudal fin morphometrics (caudal fin span, area and aspect ratio), hepatosomatic index and muscular-skeletal amount per unit length were estimated and compared within and among species by means of both parametric and non-parametric multivariate and univariate statistical procedures. Intra-specific variation was related to size and, for one species only, also to sex. Two inter-specific patterns of variation were observed: the first pattern was interpreted as a swimming ability gradient between slow benthic and more pelagic species, as a function of caudal morphometry and body characteristics; the second pattern is related to the depth the species inhabit and/or their trophic level. These two hypotheses were tested with the current data and literature information, and discussed in the context of shark swimming modes, habit and environment. Based on observed differences in caudal fin morphometrics, liver and muscular masses, this paper is the first to provide a quantitative and comparative dataset for demersal sharks as a group, and attempts to describe sample variability as a function of expected swimming ability and occupied niche (depth inhabited and/or trophic level). Siete especies de tiburones demersales, pertenecientes a 6 familias, capturadas en el sur del mar Mediterráneo, fueron seleccionadas como representantes de diferentes modos de natación, profundidad que suelen habitar y niveles tróficos. La morfometría de la aleta caudal (longitud, área y relación de aspecto), el índice hepato¬somático y la relación entre músculo y esqueleto por unidad de longitud fueron determinados y comparados entre los indivi¬duos y entre especies a través de procedimientos estadísticos paramétricos y no paramétricos, multivariados y univariados. La variación intra-específica se relacionó con el tamaño y, para una única especie, también con el sexo. Se observaron dos patrones interespecíficos de variación: el primero fue interpretado como un gradiente de la capacidad de natación entre es-pecies bentónicas y las más pelágicas, en función de la morfometría caudal y de las características corporales. El segundo se debió principalmente a la profundidad habitada y / o el nivel trófico. Asociando los datos actuales a la información existente en la literatura, estas dos hipótesis se comprobaron y se examinaron en el contexto del tipo de natación del tiburón y el am¬biente marino. Apartir de las diferencias observadas en la morfometría de la aleta caudal, el hígado y las masas musculares, este documento ofrece por primera vez una base de datos cuantitativos y comparativos sobre los tiburones demersales, como grupo, intentando describir la variabilidad muestral como una función de la capacidad de natación esperada y de los nichos ocupados (profundidad habitada y/ o nivel trófico).

Se analizaron los índices gonadosomático (IGS) y hepatosomático (IHS), la condición reproductiva y la composición bioquímica de la glándula digestiva, gónadas y músculo de las quelas de Platyxanthus patagonicus durante un período anual. En las hembras, el máximo IHS ocurrió en primavera (período de recuperación gonadal) y verano (período de máxima madurez). El máximo IGS fue alcanzado en verano, decreciendo a mínimos valores en otoño e invierno. En los machos, el máximo IGS fue observado en invierno, coincidiendo con un período de inactividad en el apareamiento. Para ambos sexos, la composición bioquímica del músculo de las quelas no difirió significativamente entre las estaciones del año, excepto por el contenido en glucógeno, significativamente menor en invierno respecto a otoño y primavera en los machos. Para ambos sexos tomados conjuntamente, el músculo de las quelas contuvo 72.4-81.2% de humedad, 12.3-19.8% de proteína, 0.3-1.0% de lípidos, 1.1-2.7% de ceniza y 0.1-1.4 de glucógeno. En ambos sexos la glándula digestiva fue el principal sitio de almacenamiento de lípidos. En el ovario, el contenido de lípidos fue mayor en primavera y verano, decreciendo a valores significativamente menores después del desove, el contenido de humedad mostró el patrón opuesto y los contenidos de glucógeno y cenizas no presentaron diferencias significativas entre estaciones. En el complejo testículos-vasos deferentes, la composición bioquímica no mostró fluctuaciones estacionales, excepto por un mayor contenido en humedad en otoño respecto al verano y la primavera. We analyzed the gonadosomatic (GSI) and hepatosomatic (HSI) indices, reproductive condition and biochemical composition of the digestive gland, gonads and claw muscle of the Patagonian stone crab over a one-year period. In females, the maximum HSI occurred in spring (gonad recovery period) and summer (maximum maturity period). The maximum female GSI values were found in summer, and fell to minimum values in fall and winter. In males, the highest GSI was observed during winter, which coincided with a non-mating period. The claw muscle biochemical composition did not significantly differ between seasons for either sex, except for the significantly lower glycogen content observed in winter relative to fall and summer in males. For both sexes, the claw muscle contained 72.4 to 81.2% moisture, 12.3 to 19.8% protein, 0.3 to 1.0% fat, 1.1 to 2.7% ash and 0.1 to 1.4% glycogen. In both sexes, the digestive gland was the main storage site for lipids. In the ovary, lipid and protein contents were higher in spring and summer, and decreased to significantly lower values after spawning. Moisture showed the opposite pattern and neither glycogen nor ash contents showed significant differences between seasons. The biochemical composition of the testes-vasa deferentia complex did not show significant seasonal fluctuations, except for higher moisture content in fall compared to summer and spring. Fil: Dima, Jimena Bernadette. Universidad Tecnológica Nacional; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Nacional Patagónico; Argentina Fil: de Vido, Norma Alicia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Nacional Patagónico; Argentina Fil: Leal, Gustavo Adolfo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Nacional Patagónico; Argentina Fil: Baron, Pedro Jose. Universidad Tecnológica Nacional; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Nacional Patagónico; Argentina

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.

The female reproductive biology of Chasmagnathus granulatus Dana, a semiterrestrial burrowing crab endemic to the southwestern Atlantic, was compared in two contrasting coastal habitats: San Antonio (SA, marine) and Mar Chiquita (MC, estuarial). Mature females were collected monthly for 1.5 years and the ovarian cycle was described using a qualitative scale. Gonadosomatic (GSI) and hepatosomatic (HSI) indexes were calculated. The highest GSI and HSI occurred early in the reproductive season in SA and during the non-reproductive season in MC. The beginning and duration of the reproductive season also differed between populations: it started later and was shorter in SA. In MC, secondary vitellogenesis continued when the reproductive season had finished, and the ovaries remained fully developed throughout the non-reproductive season (winter). Therefore, females of MC were ready to lay eggs as soon as spring environmental conditions appeared. However, SA females did not attain a fully developed ovary during winter. A limited food supply would restrict the available energy to complete secondary vitellogenesis at the end of the reproductive season in SA, after the last spawning. Thus, the vitellogenic cycle should be completed in the following spring, causing a delay in the beginning of the reproductive period. In addition, the higher temperature amplitude may cause the reproductive period in SA to end early. La biología reproductiva de las hembras de Chasmagnathus granulatus Dana, un cangrejo semiterrestre y excavador endémico del Atlántico Sudoccidental, fue comparada entre dos localidades costeras con regímenes ambientales contrastantes: San Antonio (SA, marino) y Mar Chiquita (MC, estuarial). Hembras maduras fueron recolectadas mensualmente por 1.5 años y el ciclo ovárico fue descrito usando una escala cualitativa. Los índices gonadosomático (GSI) y hepatosomático (HSI) fueron calculados. Los mayores valores de GSI y HSI tuvieron lugar al inicio de la estación reproductiva en SA, y durante la estación no reproductiva en MC. El inicio y duración de la estación reproductiva también difirieron entre las poblaciones: ésta comenzó más tarde y fue más corta en SA. En MC, la vitelogénesis secundaria continuó cuando la estación reproductiva había finalizado, y el ovario permaneció desarrollado durante la estación no reproductiva (invierno). En consecuencia, las hembras de MC estaban listas para poner sus huevos tan pronto como aparecieron las condiciones ambientales de primavera. Por el contrario, las hembras de SA no alcanzaron un completo desarrollo del ovario durante el invierno. Un suministro limitado de alimento restringiría la energía disponible para completar la vitelogénesis secundaria al final de la estación reproductiva en SA, después de la última puesta. De ese modo, el ciclo vitelogénico debió completarse en la primavera siguiente, provocando un retraso en el comienzo de la estación reproductiva. Adicionalmente, la mayor amplitud térmica provocaría que la estación reproductiva finalice más temprano en SA

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.

With regard to increasing the fish meal price, utilization of hygienic and analyzed poultry by product meal as an alternative protein source in diets for Huso huso within growth period were investigated. Six test diets isonitrogenous and isocaleric (contain 42% protein and 20 Mj kg-1 energy) were prepared. Fish meal was substituted by poultry by product at 20% (PBM20), 40% (PBM40), 60% (PBM60), 80% (PBM80) and 100% (PBM100) in base diet, respectively. A total of 180 Huso huso with average (±SD) weight of 107.89±5.9gr were stocked in 18 fiberglass tanks (Voloum:2000 lit,Temperature:20±2C 0) and fed satiation to 18 weeks. No significant differences were detected between final weight (FW),weight gain (WG) and specific growth rate of fish fed (PBM0), (PBM20), (PBM40), (PBM60) and (PBM80) respectively. The Highest protein belonged to fish fed PBM20 (%16.97±0.36) with significant difference with PBM40 (% 15.41 ± 0.67), respectively. Body lipid fish fed PBM80 and PBM100 (%6.63±0.016) (%7.49±0.17) were significantly lower than other treatments. The Synchronic hepatosomatic index increased with increasing poultry by product in diets and highest rate were found in fish fed PBM 100 , but except PBM20, visceral index in fish fed other treatments was same. The result showed that up to 80% fish meal could be replaced by poultry by product with no adverse effect on growth and feed conversion ratio for Huso huso within growth period.

In this study, the effect of short-terms starvation (0, 2, 4 and 8 days) on plasma cortisol, glucose, triglyceride and cholesterol levels and also hepatosomatic index in Siberian sturgeon, Acipenser baerii, was investigated. After acclimation to experimental conditions for 10 days using formulated diet, 180 juvenile Siberian sturgeons (mean weight ± S.E.=19.3±0.4, n=15) were randomly distributed among twelve circular, 500l, fiber glass holding tanks with a flow-through system. In this study, control fish (C) were fed with formulated diet to apparent satiation four times daily throughout the experiment. The other three groups were deprived from feed for 2 (T1), 4 (T2) and 8 (T3) days, respectively. Blood samples were taken at the end of the starvation periods for biochemical analyses. Plasma cortisol, triglyceride and cholesterol levels were not significantly different between control and starved fish at the end of the food deprivation periods, but plasma glucose levels were significantly lower in the starved groups, compared to the control fish. HSI index significantly decreased in all starvation groups, except T1, in comparison to the control. The results suggest that energy reserves mobilization during starvation in Siberian sturgeon may be achieved without the involvement of cortisol. Moreover, in this species there are clear indications of metabolic adjustment ability to short periods of food deprivation.

This study evaluated the effect of feed supplementation (at doses of 0, 50, 100, 150, and 200 mg/kg) with SALUTO®, a microencapsulated blend of essential oils including carvacrol, cinnamaldehyde, 1,8-cineol, and pepper oleoresin, in Nile tilapia (Oreochromis niloticus) broodstock on reproductive and growth parameters during the initial phase of rearing. The growth parameters, somatic indexes and gonadal and hepatic parameters were analyzed. Quantitative parameters of growth, ovary fat and crude protein were not affected by supplementation of the additive. However, an increase in crude protein in the female liver was observed in correlation with increased essential oil levels. The female hepatosomatic index was also correlated with supplementation of essential oils. Feeding Nile tilapia broodstock diets containing an essential oil compound (SALUTO®) affects only the females, promoting an increase in liver protein inclusion and hepatosomatic index without impairing performance.

The present study investigates the response of three hepatic biomarkers in adult sea bass (Dicentrarchus labrax, Linnaeus 1758) caged at a wastewater outlet of an oil refinery with fish caged at a pristine site used as controls. The biomarkers that were investigated were the hepatosomatic index (HSI), 7-ethoxyresorufin-O-deethylase (EROD) activity and glutathione-S-transferase (GST) activity. In addition, we have measured the levels of polycyclic aromatic hydrocarbons (PAHs) and selected heavy metals (lead, cadmium, mercury, copper and zinc) in sediment samples at the polluted site. Although the polluted site had high environmental levels of PAHs and heavy metals, there was no difference in hepatic EROD activity and HSI between fish caged at the polluted site and controls. On the other hand, GST activity was significantly lower in fish caged at the polluted site compared to controls. Our results point out that the studied biomarkers have limited use in environmental risk assessment studies, at least when caged adult sea bass is used as the sentinel species and complex toxicant mixtures are involved.

International audience; Alternations of reproductive physiology were studied in the male goldfish (Carassius auratus L.) exposed to environmentally relevant concentrations (0.6, 4.5 and 11.0 μg/L) of bisphenol A (BPA) at days 10, 20 and 30 after exposure. Significant effects of BPA concentration, exposure time and their interactions were observed on testosterone (T), 11-ketotestosterone (11-KT) and sperm motility and velocity, but gonadosomatic index (GSI), hepatosomatic index (HSI) and 17β-estradiol (E2) were not affected. Vitellogenin (VTG) was only affected by BPA concentration. The T and 11-KT levels were significantly decreased in the BPA-treated groups after 20 or 30 days. Sperm motility was significantly decreased at 15, 30, 60 and 90 s post-activation in the BPA-treated groups after 20 or 30 days. But, significant decrease in sperm velocity was observed at 30, 60 and 90 s post-activation in the BPA-treated groups at all exposure times. The VTG was significantly increased in the males exposed to 11.0 μg/L at day 30 after exposure. The GSI, HSI and E2 did not differ between the BPA-treated groups and control. The present study shows that the decrease of sperm quality is concurrent with the decrease of androgens and increase of VTG. The results suggest adverse effects of BPA on sperm motility and velocity via modifications of testicular steroidogenesis that might correspond to alternation in sperm maturation.

Bioaccumulation of Cu, Zn, Hg in muscles and liver tissues of stellate sturgeon (Acipenser stellatus) from the southern Caspian Sea was measured. Effects of condition factor (CF), age and hepatosomatic index (HSI) on metal accumulation were also determined. Some 40 stellate sturgeons were collected using gill nets in winter and spring 2007-2008 from the southern shores of the Caspian Sea. Total (TL) and fork (FL) length and weight of all specimens were measured. Cross sections of first ray of pectoral fins were used for age determination. Muscle and liver samples were taken and transported to the laboratory in ice packs and kept in -20 °C prior to analyses. In the laboratory samples were oven dried, digested with HClO3 and HNO3 and diluted with dionized water to 50cc to measure Cu, Zn, and Hg concentration with a flame spectrophotometer. Sequence of metals in Acipenser stellatus was Zn>Hg> Cu in muscle tissues and Zn>Cu>Hg in liver samples. Concentration of Zn was slightly in correlation with age (R= 0.3). A negative correlation was observed between Zn concentrations with condition factor (R = -0.3). Zn concentrations were negatively correlated in muscle tissues (R = -0.3). The results were compared to international standards proposed by MAAF, EEC and NHMRC. Our study showed that accumulation of heavy metals in sturgeon tissues was influenced by concentration of metals in sediment and the physiological state of fish. Article includes abstract in Farsi on last page.

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.

12 páginas, 8 figuras, 4 tablas., The present study describes the reproductive biology, population structure and life history traits of the abundant intertidal crab Xantho poressa. Between March 2007 and April 2008, a total of 1918 individuals were collected in Corrales de Rota (south-western Spain), a human-modified intertidal habitat characterized by an artificial high complexity. Suitable refuges for crabs (cobbles and boulders) are very abundant in this area and density (maximum of 50 ind*m−2) was directly related with the area covered by these stones. In spring and summer, size–frequency distributions showed a polymodal pattern with seasonal variations related to the incorporation of juveniles to the adult population. Newly settled juveniles were not found in the Corrales suggesting an ontogenetic migration from a distant recruitment habitat. The annual reproductive cycle was seasonal and successive peaks in the abundance of ovigerous females were observed in late spring and summer. Females probably produced multiple broods during a long intermoult period. The gonadosomatic index had a cyclic pattern of variation with peaks two weeks prior to those of ovigerous females; it was lower during the non-reproductive season. The hepatosomatic index was high during spring, decreased during summer and increased gradually at the end of the reproductive season. There was a monthly cycle of larval release resulting from a combination of a cyclic and synchronic ovarian maturity, oviposition and incubation; hatching took place during neap tides when the moon was at last quarter. The adaptive significance of the rhythmic reproduction and hatching observed may not be explained by the predator avoidance hypotheses. The overall sex-ratio did not differ from 1:1 but one male and several females coexist under a stone, indicating a female biased operative sex-ratio. The combination of a complex habitat, its use, and a strong sexual dimorphism suggest a refuge–defence polygenic mating system. The survival and fitness of X. poressa in the Corrales de Rota are probably enhanced by the availability of shelter, a consequence of a highly complex habitat, and probably, of human activity., This study was partially carried out during a 6-month visit by E.D.S. to the Instituto de Ciencias Marinas de Andalucía (ICMAN), supported by the Ministerio de Educación y Ciencia de España (MEC) through a grant for foreign professors and researchers visiting laboratories in Spain during their sabbatical years (SAB2005-0170).

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.

El objetivo del presente trabajo es determinar la influencia de los niveles de lípidos en dietas formuladas sobre el crecimiento, supervivencia, índice hepatosomático (HSI) y composición proximal del músculo e hígado de la brótola.Se fabricaron tres dietas diferentes (40% proteína cruda) con 3%, 6% y 10% de aceite de pescado, obteniendo un 5%, 8% y 11% de lípidos crudos, respectivamente. La tasa diaria de alimentación fue del 3%. Al finalizar el experimento a los 40 días, los animales fueron pesados y se tomaron muestras de tejido muscular y hepático.La mayor tasa de crecimiento en peso se obtuvo en el grupo alimentado con los niveles más bajos de lípidos. Se observaron diferencias significativas (P

8 pages, 3 figures, 1 table, An analysis of the condition (Fulton’s K) of cod (Gadus morhua) off Greenland during autumn in the period 1982–1998 is presented. The paper addresses the interannual variations in condition and attempts to relate these to variations in water temperature. No size, age, sex, maturity nor geographical differences were observed. Condition of cod was positively related to water temperature. Mean condition factor calculated from total weights for the entire period was 0.89. Hepatosomatic and gonadosomatic indices are also presented for year 1998. Overall, the condition of cod off Greenland was among the lowest observed in natural populations of this species

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.