Abstract Life history strategies determine and influence many aspects of species fitness. In this study, we describe the reproductive biology - reproductive cycle, sperm storage, and sexual maturity - of Thamnodynastes strigatus in South Brazil. We analyzed 49 individuals (25 males and 24 females) from herpetological collections. The reproductive cycle of males and females was described considering the morpho-anatomical and histological changes in the testes, ductus deferens, and kidney, as well in the ovary and oviduct. The age at the onset of sexual maturity was determined by skeletochronology of the caudal vertebra. The reproductive cycle is seasonal semi-synchronous and most individuals have a reproductive peak in spring and summer. The seasonal biennial reproductive cycle and viviparity are two phylogenetically conserved characters in Tachymenini snakes. Thamnodynastes Strigatus females store sperm in the utero-vaginal junction furrows during autumn. There were no differences between the ages of sexual maturity of males (4-11y) and females (4-12y). Females reach sexual maturity at larger body sizes, and this may confer an adaptive advantage due to a higher fecundity potential. Herein, we confirmed the previously described seasonal biennial reproductive cycle of T. strigatus through histological analysis.

Abstract: Skeletochronology is the most accurate method to estimate a population age structure. The methodology is based on the analysis of secondary bone tissue in order to count growth rings. This study aimed to provide initial data, allowing researchers to further work out in the age of individuals and populations, sampling evidence of the presence of growth rings in 11 native species (representing nine families) of a subtropical region of southern Brazil. Four bone samples of each specimen were used to perform the skeletochronological analysis: the penultimate phalanges of the 3rd and 4th fingers, the humerus, and the femur. The presence of growth rings was confirmed in the periosteal layer of the bones of all analyzed species. In comparison with phalanges, growth rings of humeri and femora are more irregular and less distinguishable. This is the first record of growth rings to the native species herein analised. The skeletochronology was proved to be an effective tool in determining the age of anuran amphibians from a subtropical region, since this environment presents well defined climatic seasonality.

RESUMO: Substâncias húmicas são compostos orgânicos que possuem elevado peso molecular e são formadas pela decomposição da matéria orgânica de plantas. As substâncias húmicas compreendem ácidos húmicos, ácidos fúlvicos e humina. Os ácidos húmicos (AH) têm mostrado serem capazes de proporcionar proteção parcial das membranas biológicas de peixes em águas com baixo pH, substituindo a ação protetora do Ca2+. Assim, este estudo teve como objetivo observar o crescimento de juvenis de jundiá ( Rhamdia quelen ) expostos a pH's 5,5 e 6,5 com diferentes níveis de AH: 0, 10, 25 e 50mg L-1. Os resultados demostram que, independentemente do pH, o AH foi altamente prejudicial para o crescimento do jundiá, uma vez que, quanto maior era a concentração de AH, menor era o ganho de peso e a ingestão de alimentos, resultando em menor biomassa e taxa de crescimento específico inferior dos juvenis. Assim, os AH são extremamente prejudiciais para o desempenho de juvenis de jundiá nas concentrações testadas.

ABSTRACT: Humic substances are organic compounds that possess high molecular weight and are formed by the decomposition of plant materials. Humic substances comprise humic acids, fulvic acids and humin. Humic acids (HA) have shown to be able to provide some protection to biological membranes of fish in water with low pH, replacing the protective action of Ca2+. Thus, this studyaimed to observe growth of silver catfish ( Rhamdia quelen ) juveniles exposed to pHs 5.5 and 6.5 and to different levels of HA: 0, 10, 25 and 50mg L-1. Results showed that, irrespective of pH, HA was highly detrimental to silver catfish growth, since the higher the concentration of HA, the lower the weight gain and feed intake, resulting in lower biomass and lower specific growth rate of juveniles. Hence, HA is extremely damaging to the performance of silver catfish juveniles in the tested concentrations.

This study evaluates whether humic acid (HA; Aldrich) protects the silver catfish, Rhamdia quelen (Quoy & Gaimard, 1824), against exposure to acidic pH. Survival, levels of Na+, Cl- and K+ plasma, hematocrit, hemoglobin and erythrocyte morphometry were measured. Fish were exposed to 0, 10, 25 and 50 mg L 1 HA at four pH levels: 3.8, 4.0, 4.2 and 7.0 up to 96 hours. None of the fish exposed to pH 3.8 survived for 96 hours into the experiment, and survival of fish subjected to pH 4.0 decreased when HA concentration increased. Plasma Na+ levels decreased when pH was acidic, with no influence of HA, while Cl- levels declined at low pH with increased HA concentration. The levels of K+ at pH 4.0 and 4.2 increased without HA. Hematocrit and hemoglobin augmented under the effect of HA. At pH 4.0 and 4.2, erythrocytes of fish not exposed to HA were smaller, an effect that was partially offset by the presence of HA, since the values at pH 7.0 were higher. Although HA showed some positive effects changes in hematological and plasma K+ª in silver catfish caused by exposure to acidic pH, the overall findings suggest that HA does not protect this species against acidic pH because it increased mortality and Cl- loss at pH 4.0.

Nos procedimentos em piscicultura, os peixes são facilmente estressados nas diferentes etapas de criação. Assim, é importante o uso de anestésicos para prevenir injúrias físicas e promover a redução do metabolismo, resultando em melhor bem-estar aos peixes. O objetivo deste estudo foi analisar a indução anestésica em juvenis de carpa húngara (Cyprinus Carpio) expostos a diferentes doses de eugenol (20; 30; 40 e 50mg/L), ketamina (300; 600; 900 e 1200mg/L), xilazina (800; 1100; 2000mg/L) e da associação ketamina/xilazina (300/300; 600/600; 900/900 e 1200/1200mg/L). Cada dosagem foi testada em grupos de dez peixes escolhidos ao acaso (n=10), submetidos individualmente ao banho com anestésico em recipiente contendo 1 litro de água. Todos os procedimentos experimentais foram iguais nos ensaios. Após, foram analisados os tempos de anestesia (TA) e de recuperação (TR). Os anestésicos eugenol, ketamina e a associação ketamina/xilazina permitiram que os juvenis de carpa húngara atingissem a anestesia profunda. Entretanto, os dois últimos produtos testados causaram mortalidade em algumas doses. A xilazina não promoveu anestesia em nenhuma das doses testadas. Dentre os anestésicos testados, o eugenol na dose 50mg/L, demonstrou indução anestésica e tempo de recuperação satisfatório para juvenis de carpa.

In the aquaculture procedures, the fishes are easily stressed in differetn rearing phases. So, is important the use of anesthetics for to prevent physical injuries and promote metabolism decrease, resulting in improved welfare for fish. The aim of this study was analyze the anesthetical induction of Hungarian carp fingerlings (Cyprinus Carpio) displayed of the different dosages of eugenol (20, 30, 40 and 50mg/L), ketamine (300, 600, 900 and 1200mg/L), xylazine (800, 1100, 2000mg/L) and the ketamine/xylazine association (300/300, 600/600, 900/900 and 1200/1200mg/L). Each dosage was tested for ten fish, individually subjected to the anesthetic bath with container containing 1 liter of water. All experimental procedures were the same as in the tests. After, it was analyzed the anesthetic time (TA) and the recovery time (TR). The anesthetics eugenol, ketamine and the ketamine/xylazine association allowed the deep anesthesia, but xilazine didn't allow it. Among the anesthetics tested, eugenol at 50mg/L demonstrated better anesthetic induction and recovery time for carp juveniles.