Length-weight relationships (LWR) were estimated for 17 species and total length at first maturity (L50) for three species of freshwater fishes from the Miranda River, southern Pantanal, Brazil. The b values were compared for some species in the Paraguay River basin with the northern (Cuiaba´River) part of the basin; differences in length-weight relationships were significantly different for Pseudoplatystoma corruscans, P. reticulatum (syn. P. fasciatum). First references on L50 and LWR are presented for two and eight fish species, respectively, as well as the new maximum total length for two species.

In

Aim: This study aimed to evaluate influence of hydrological variation, ontogeny and interspecific variation in the feeding activity and diet composition for P. nattereri and S. marginatus in floodplain of Negro River, South Pantanal. Methods: The samples were taken with the use of gillnets and cast nets of different sizes, from October/2005 to August/2008. Results: We sampled 748 specimens, 442 of P. nattereri and 306 of S. marginatus. We identified 31 items in the dry and 14 in the flood season for P. nattereri, and 29 items in the dry and eight in the flood season for S. marginatus. For both species, fish was the predominant food item in both seasons. The PERMANOVA results showed that the diet varied significantly between the two species (p<0.001), during ontogenetic development (p<0.001) and seasonally (p=0.024). The ancova results suggests that the intensity of food intake was higher in the dry season (p<0.001) for both species. The niche breadth varied only between studied species with S. marginatus presenting higher niche breadth than P. nattereri. Conclusion: Piranhas feed more during dry season, probably because in this period food is more varied and abundant, due to the concentration of fish in the main river channel. There were ontogenetic changes in the diet, with no feeding overlap between the two species, probably because of differences in preference for some items and differences in feeding behavior displayed during hunting attacks.Keywords: Serrasalminae, diet, feeding overlap, trophic ontogeny, Nhecolândia.Resumo: Objetivos: Este trabalho tem como objetivo avaliar a influência da variação hidrológica, da ontogenia e da variação interespecífica na atividade alimentar e composição da dieta de P. nattereri e S. marginatus na planície de inundação do Rio Negro, Pantanal Sul. Métodos: As amostragens foram realizadas com o uso de redes de espera e tarrafas com diversas malhagens no período de outubro/2005 e agosto/2008. Resultados: Foram coletados um total de 748 indivíduos, 442 de P. nattereri e 306 indivíduos de S. marginatus. Identificamos 31 itens alimentares no período da seca e 14 na cheia para P. nattereri e 29 itens alimentares no período da seca e oito na cheia para S. marginatus. Para ambas as espécies, peixes foi o item predominante em ambas as estações. Os resultados da PERMANOVA mostraram que a dieta variou significativamente entre as espécies (p<0,001), durante o desenvolvimento ontogenético (p<0,001) e sazonalmente (p=0,024). Os resultados da ANCOVA sugerem que a intensidade da tomada de alimento foi maior na estação seca (p<0,001), para ambas as espécies. A amplitude de nicho 382 Ferreira, FS. et al.Acta Limnologica Brasiliensia variou entre as espécies estudadas, S. marginatus apresentou uma amplitude de nicho maior do que P. nattereri. Conclusão: As piranhas se alimentam mais durante a seca, provavelmente porque neste período o alimento é mais variado e abundante, devido a concentração de peixes no canal principal do rio. Houve mudanças ontogenéticas na dieta, sem sobreposiç...

No abstract

The present work depicts a compilation of mechanical properties of 282 distinct multicomponent Ti-based alloys and their respective microstructural features. The dataset includes the chemical composition (in at.%), phase constituents, Young modulus, hardness, yield strength, ultimate strength, and elongation. Each entry is associated with a high-quality experimental work containing a complete description of the processing route and testing setup. Furthermore, we incorporated flags to the dataset indicating (a) the use of high-resolution techniques for microstructural analysis and (b) the observation of non-linear elastic responses during mechanical testing. Oxygen content and average grain size are presented whenever available. The selected features can help material scientists to adjust the data to their needs concerning materials selection and discovery. Most alloys in the dataset were produced via an ingot metallurgy route, followed by solubilization and water quench (≈58%), which is considered a standard condition for β-Ti alloys. The database is hosted and maintained up to date in an open platform. For completeness, a few graphical representations of the dataset are included.

RESUMONo presente trabalho foram analisados os parâmetros de crescimento, a relação peso-comprimento e a influência da variação sazonal do rio Miranda, alto rio Paraguai, sobre o período reprodutivo de Prochilodus lineatus. As amostragens foram realizadas mensalmente entre abril/2000 e outubro/2003. A equação que descreve a relação peso-comprimento total para fêmeas foi Pt=0,01213*Ct 3,039 e para os machos Pt=0,01322*Ct 3,012 . O comprimento total assintótico estimado foi de 55,68cm e taxa de crescimento K = 0,46/ano e Rn = 0,183 foram estimados pela frequência de classes de comprimento. O tamanho de primeira maturação (L50) foi estimado em 28,2cm. O índice gonadossomático (IGS) variou significativamente entre os meses (H = 136,61; p < 0,01), com valores mais elevados entre setembro e dezembro, contudo foram encontradas fêmeas maduras de agosto a fevereiro. O IGS esteve positivamente correlacionado com a duração do dia (rs = 0,55; p < 0,05) e com a precipitação (rs = 0,65; p < 0,05), contudo, não esteve correlacionado com o nível do rio (rs = 0,48; p = 0,1), ainda que no período de enchente seja perceptível a co-variação entre GSI e o nível do rio. O aumento no comprimento do dia e o início das primeiras chuvas parecem atuar como sinais preditores para que as fêmeas possam iniciar a atividade reprodutiva, a fim de garantir aos ovos e larvas as condições ambientais ideais encontradas nos meses subsequentes de cheia, fato este verificado pela alta proporção de fêmeas maduras de setembro a dezembro. A expectativa de vida de 6,5 anos foi compatível com as 6 coortes estimadas pela curva de crescimento. Palavras-chave: tamanho de primeira maturação; crescimento; Pantanal. ABSTRACT POPULATION STRUCTURE, BREEDING SEASON AND GROWING OF Prochilodus lineatus INHEADWATER OF MIRANDA RIVER, UPPER PARAGUAI RIVER. In the present paper we analyzed growth parameters, length-weight relationship and the influence of seasonal variation of Miranda river, upper Paraguay River, on breading season of Prochilodus lineatus. The samples were accomplished monthly from April/2000 to October/2003. The length-weight relationship described for females was PT=0.01213*CP 3.039 and for males was PT=0.01322*Ct 3.012 . The estimated asymptotic total length was 55.68cm and the growth rate K = 0.46 and Rn = 0.183 were estimated by frequency of length classes. The estimated size at first maturity (L50) was 28.2cm. The gonadossomatic index (GSI) varied significantly among months (H = 136.61; p < 0.01), with significant higher values from September to December, however ripe females were caught from August to February. GSI was positively correlated with the day length (rs = 0.55; p < 0.05) and with rainfall (rs = 0.65; p < 0.05), however, it was not correlated with the river level (rs = 0.48; p = 0.1). The increasing in the duration of the day and the begin of the first rains seem to act as cues for females start the breeding activity, in order VICENTIN, W. et al. Oecol. Aust., 16(4): 891-904, 2012 892 to provide to eggs and larvae the optimum environmen...

In order to inventory the metazoan endoparasites of Serrasalmus marginatus, 91 specimens were examined. Studies on the parasitofauna of piranha Serrasalmus marginatus (Valenciennes, 1837) are scarce and mostly have focused on the taxonomy of some groups. The most remarkable reports on endoparasites in S. marginatus include that of Tanaka (2000) who reported Procamallanus (Spirocamallanus) inopinatus, specimens of Capilariidae, Railliet, 1915, and Kritskyia sp. and that of Böeger et al. (2001) who described Kritskyia annakohnae in ureters and urinary bladder, both studies in the Paraná River basin. The hydrographic network of the Pantanal, with a variety of species of teleost fishes, has few records on parasite faunas, including piranha (S. marginatus) that is widely distributed in the Paraguay River basin.Thus, with the aim of registering species composition of metazoan endoparasites in S. marginatus, there were necropsied 91 specimens caught with hooks and cast nets from

No abstract