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Junk, Wolfgang Johannes
Efeitos da fragmentação florestal sobre as assembléias de peixes de igarapés da zona urbana de Manaus, Amazonas
(Instituto Nacional de Pesquisas da Amazônia - INPA, 2007)
Anjos, Hélio Daniel Beltrão dos
The city of Manaus is growing in an accelerated and disordered way, what provokes the fragmentation of the forest and condemns the urban streams to the disappearance. With those streams, an important portion of the local aquatic biodiversity gets lost, before even of being appropriately known. We studied the stream fish assemblages in 15 urban forest fragments, seeking to evaluate the effects of the forest fragmentation and structural characteristics of the streams on the composition and diversity of the ictiofauna. 41 species of fish were collected, of six orders and 11 families. Species richness varied from one to 14 species in 200m stream reaches. Streams subjected to anthropogenic impacts presented conspicuous changes in limnological parameters and in the composition and structure of the assemblies of fish as well. Preserved streams contained richer fish assemblages, associated to high values of dissolved oxygen and low values of conductivity and pH, whereas the inverse situation was registered in streams polluted by domestic sewage. The similarity in the composition of fish assemblages was not correlated significantly with the linear distance among the fragments, neither with the hydrological connectivity among the streams. Differences in the original environmental characteristics of the streams, as well as the subsequent isolation of populations of fish for chemical barriers (highly polluted streams among the forest fragments) can be responsible for the differences now observed in the composition of species in nearby streams. The species richness found in each stream (1-14 species) was small in relation to the overall species richness found (41 species), indicating a high Beta diversity. Such results indicate that the conservation of the forest fragments of the urban area of Manaus is critical for the maintenance of the general fish diversity, once the fragments contain different subsets of regional ichthyofauna. Therefore, the destruction of any fragment may result in the local extinction of one or more species of fish, with an important loss of the regional biodiversity.
Consumo de oxigênio e fluxo iônico de ovos e larvas de tambaqui, Colossoma macropomum Cuvier, 1818 (Characidae, Serralminae) em diferentes temperaturas
(Instituto Nacional de Pesquisas da Amazônia - INPA, 2001)
Pérez, Cristhian Amado Castro
The main goal of this study is the analysis of metabolic changes during the ontogeny of tambaqui, Colossoma macropomum. Thus, we have analyzed the oxygen consumption, the total hardness, and the flux rates of Ca, Mg, Na and K at different embryonic and larval stages of tambaqui. Temperature influences on these parameters were also analyzed. Changes in oxygen consumption, total hardness, and Ca, Mg, and Na flux rates were observed during the embryonic and larval stages of tambaqui. Temperature changes between 24 and 30°C did not affect these parameters. Changes in total hardness, Ca and Mg flux rates were similar in all developmental stages, suggesting similar osmoregulatory properties of these ions. The K flux rate was not altered during the embryonic and larval development but it changed in eggs and larvae exposed to 24 and 30°C. The effluxes of the analyzed ions suggest that ion poor water is not recommended for the initial development of tambaqui. This study represents an addition to the scarce literature related to metabolism aspects of tropical fish, in particular during the transition from egg to larvae.
Estrutura populacional do tetra cardinal Paracheirodon axelrodi, Schultz 1956 (Characiformes; Characidae) no médio rio Negro, Amazonas – Brasil
(Instituto Nacional de Pesquisas da Amazônia - INPA, 2017)
Rodrigues, Paola Karoline de Sousa
The estimation of population parameters in fish is essential for the interpretation of the life aspects of the strategy linked to its reproduction and growth, providing subsidies for the development of effective measures in the management of fishery resources. Cardinal tetra (Paracheirodon axelrodi) is a commercially important species in the ornamental fishery in the state of Amazonas, however, its dynamic population is little known. This study aimed to describe and evaluate the population structure of six streams with ornamental history fishing present on the left bank of the middle Rio Negro. The collections were carried out monthly from February 2016 to January 2017 by using three traps Cacuri for one hour in each stream. In the laboratory, the specimens were measured (SL in mm), weighed (g) and had their sex determined. The analyzes included determination of the length structure, growth parameters (L∞ and k), sex ratio, weight - length ratio, condition factor, duration of first sexual maturation (L50), reproductive period and fecundity. A total of 15.618 specimens were collected, females reached greater length than males in all streams. However, considering all collections, the mean length and recruitment period are similar for all collections in all streams. The asymptotic length of the specie was 28,35 mm and an growth rate was 0,59.year¹. The sex ratio varied between 1F:1M and 1,3F: 1 M in all streams. The weight-length relation is of the positive allometric type in all the streams and the condition factor was significant in all the streams between the sexes, suggesting a better condition for the females and males in the reproductive period. The length of first sexual maturation was 14.95 mm for males and 15.44 mm for females with a period of reproduction of cardinal tetra occurring in the period of flood and fertility ranging from 234 to 1386 oocytes with total spawning. With the obtained results, it is possible to propose measures that permeate the conservation of the species, emphasizing the due care of the fishing in the period by which the reproduction takes place and the recruitment of the young that is directly connected to the seasonality.
Riqueza e abundância de insetos galhadores associados ao dossel de florestas de terra firme, várzea e igapó da Amazônia Central
(Instituto Nacional de Pesquisas da Amazônia - INPA, 2007)
Julião, Genimar Rebouças