No abstract

assemblage structure in a marginal lake disconnected from the submedium São Francisco River, Pernambuco. Biota Neotrop., 9(3): http://www. biotaneotropica.org.br/v9n3/en/abstract?article+bn01809032009.Abstract: Samplings with various fishing devices were undertaken between March 2007 and February 2008, in the Curralinho lake, a marginal pond located in the submedium São Francisco river, aiming at evaluating the fish fauna composition after its isolation from the river channel and water depletion. A total of 4,638 specimens was collected, with a biomass of 129,782.84 g, distributed in 16 families and 47 species from the Orders Characiformes, Cyprinodontiformes, Siluriformes, Perciformes, Gymnotiformes and Clupeiformes. Characiformes were most abundant and 87.3% of the specimens were small (<100 mm) or medium-sized (<200 mm). Among the species collected, 26.7% were constant, 35.6% accessory and 37.8% accidental. Characidae encompasses most of the species and individuals, followed by Acestrorhynchidae. Moenkhausia costae, Triportheus guentheri, Pygocentrus piraya and Prochilodus argenteus were present in all samples. Invertivores and piscivores dominated quantitatively and their biomass indicate a predominance of predators, with detritivores presenting the second greatest biomass. Resident species prevailed, with few individuals of migratory fish belonging to Anostomidae and Prochilodontidae families and Salminus franciscanus. Fish richness, diversity and equitability were relatively high throughout the period of study. It may be concluded that the Curralinho lake is an important shelter, feeding and resting ground for the ichthyofauna, mainly for forage fish that serve as the basis of the trophic chain and fisheries´ sustainability. Therefore, there is an urgent need of environmental policy and management practices development that would preserve habitat integrity and functionability of their role in the conservation of ichthyodiversity of this stretch of the São Francisco basin. Keywords: Curralinho, San Francisco, fish, ichthyodiversity. LUZ, S.C.S., EL-DEIR, A.C.A., FRANÇA, E.J. & SEVERI, W. Estrutura da assembléia de peixes de uma lagoa marginal desconectada do rio, no submédio Rio São Francisco, Pernambuco. Biota Neotrop., 9(3): http://www.biotaneotropica.org.br/v9n3/pt/abstract?article+bn01809032009.Resumo: Foram realizadas coletas utilizando vários apetrechos de pesca, entre os meses de março/07 e fevereiro/08, na lagoa Curralinho, uma lagoa marginal no trecho submédio do rio São Francisco, com o objetivo de avaliar a composição ictiofaunística após seu isolamento da calha principal do rio e deplecionamento de água. Foi coletado um total de 4.638 espécimes, com uma biomassa de 129.782,84 g, distribuídos em 16 famílias e 47 espécies das ordens Characiformes, Cyprinodontiformes, Siluriformes, Perciformes, Gymnotiformes e Clupeiformes. Observou-se que os Characiformes foram os mais abundantes, com 87,3% dos exemplares de pequeno (<100 mm) e médio porte (<200 mm). Dentre as espécies encontradas, 26,7% são con...

In Brazil, more than 150 non-native fish species have been introduced either intentionally or unintentionally, mainly due to aquaculture, fishery improvement and ornamental trade. The non-native jaguar guapote Parachromis managuensis was recorded in two artificial ponds, four rivers, one stream and two reservoirs, ecosystems belonging to the Una, Ipojuca, Capibaribe and Pajeú River basins, Pernambuco, northeastern Brazil. The sampling period was between October 2006 and July 2015. A total of 376 individuals of P. managuensis was captured by seines, casting nets and gillnets. This species may have been introduced in the study sites by accidental release during pond drainage in fish farms, stocking for the purpose of animal protein production or by aquarium dumping. The presence of various ontogenetic life stages in all studied environments is a strong evidence that the species is established. Seven management actions are proposed to prevent further introductions of P. managuensis in other environments of the region.

The present study describes the external morphology and morphometry of the initial development of Atherinella brasiliensis, and contributes toward broadening knowledge on its biology. A total of 88 larvae and 14 juveniles were used to characterize the morphological development and analyze body proportions. Fish with standard lengths (SL) from 1.4 to 77 mm were used in the study. Larvae hatch at an average of 1.4 mm SL. In the preflexion stage, the larval body is enveloped by a finfold, which begins behind the head. Pectoral fins are the first to be formed and preflexion larvae have four characteristic dendritic chromatophores on the head. The flexion stage begins at an average of 4.4 mm SL; dorsal and anal fins already exhibit pterygiophores and a terminal, somewhat up-turned mouth. At 6.8 mm SL, the flexion stage ends. In the postflexion stage, larvae present greater ossification of the dorsal and anal fin rays, exhibit pelvic fin buds and a darkening of lateral pigmentation. At an average of 8.8 mm SL, head pigmentation intensifies and pelvic fins exhibit conspicuous ossifying rays. Larvae at 11.8 mm SL have all fins formed; the second dorsal fin is the last to be formed at an insertion point posterior to the anal fin. The juvenile period begins at approximately 12 mm SL. At this stage, A. brasiliensis has an anal fin located at the median portion of the body and the posterior end of pectorals surpasses the origin of pelvic fins, which are located at the midpoint between the pectoral and anal fins. Scales are present on the dorsal-lateral region behind the head. The morphological features of A. brasiliensis herein described allow an adequate identification of its larvae and differentiate them from hemiramphid and other atheriniform larvae, thus broadening knowledge on the larval biology of the species.

No abstract

The accuracy of traditional methods to sample planktonic microcrustaceans depends on two assumptions: that organisms are alive during sampling and that all carcasses can be identifi ed despite their degradation state, but fresh carcasses are not easy to distinguish by traditional methods. Previous studies about mortality have shown that neglecting dead organisms can provide biased ecological information.Thus, our objective was to determine the mortality rate and the proportion of dead microcrustacean in three tropical reservoirs. Sampling was carried out in 12 stations during two periods. The proportion of dead organisms was verifi ed using aniline blue and it varied between 0.6% and 90.6%. The carcass decomposition period varied between 3 to 16 days and microcrustaceans mortality rate varied between 0.005 and 0.314 d -1 .Traditional preservation techniques with formalin do not signifi cantly overestimate species abundance. However, these values should not be disregarded, because corrected (disregarding organisms that were dead) and formalin-preserved abundances were correlated with distinct limnological descriptors. Therefore, the traditional formalin preservation technique could provide misleading ecological interpretations. Other studies over larger temporal scales in addition to experiments to evaluate the effects of viruses, parasitism and the toxic effects of cyanobacteria on zooplankton would enlighten mortality rate patterns in freshwater ecosystems.

Aim The present study aimed to estimate the sexual maturity, growth and mortality rates of the jaguar guapote, Parachromis managuensis, an introduced fish species in the Brazilian semiarid region. Methods Specimens were collected between December 2015 and November 2016, in a dam at Serra Talhada municipality, Pernambuco, where the species was abundant. Results In total, 520 individuals were analyzed, with total lengths (TL) varying between 23 and 240 mm. Length at sexual maturity varied between 130.87 and 140.68 mm TL (Mean = 135.78 mm TL). Through the modal progression of monthly frequency distributions, the following growth parameters were obtained according to the von Bertalanffy model: L∞ = 341.40 mm, k = 0.840 and t0 = -0.035 year-1. Ages varied from 0.05 to 1.41 year, and an age at first maturity between 0.48 and 0.53 year (Mean = 0.51 year), with the largest part of the sample (72.64%) made of adult individuals. Natural mortality rates (M) were estimated from three different methods, varying between 1.53 and 3.04, with a mean of 2.27. Conclusions P. managuensis shows fast growth and maturation and high natural mortalities, which grants it biological advantages when compared to native species from the same trophic level in the area.

O objetivo deste trabalho foi avaliar a dinâmica da comunidade fitoplanctônica durante a alevinagem de tilápia do Nilo, Oreochromis niloticus, com tecnologia de bioflocos. Adotou-se um delineamento experimental inteiramente casualizado com 6 tratamentos e 4 repetições, sendo testadas três fontes de carbono: melaço (ME), açúcar (AC) e fécula de mandioca (FE), nas relações carbono/nitrogênio (C:N) 10:1 e 20:1. As coletas de fitoplâncton foram realizadas semanalmente durante 63 dias, em amostras de 5 L de água filtradas numa rede de plâncton com malha de 25 μm. A comunidade fitoplanctônica do ambiente de cultivo esteve representada por 17 gêneros, distribuídos entre as classes Bacillariophyceae, Chlorophyceae, Cyanophyceae, Euglenophyceae e Fragilariophyceae. Em termos de gênero, pode-se concluir que a Pseudanabaena e Synechococcus foram os principais integrantes responsáveis pela dominância da Cyanophyceae em todos os tratamentos. A Chlorophyceae foi a segunda classe mais diversificada, tendo como principais gêneros Chlorella e Scenedesmus. A fonte de carbono que mais influenciou no desenvolvimento do fitoplâncton foi o melaço, na relação carbono:nitrogênio 20:1.