DOI: 10.3897/zoologia.37.e51603

Authors: Dalia A. Sabry, Dina El-Badry

Abstract: The purpose of this study was to investigate the influence of constant bright light on the cornea and retina of Clarias gariepinus (Burchell, 1822) and to examine whether it can change after constant exposure to dim light. Twenty-one adult individuals of C. gariepinus were divided into three groups (n = 7). The first group was maintained under normal light (NL). The second group was exposed to the intense bright light (BL) (3020 Lux) of white light lamps for seven days. The third group was exposed to dim light for seven days (DL) following the previous exposure to intense bright light for seven days. The eyes of each fish group were removed and fixed. The following aspects of the eye were investigated: histopathological, immunohistochemical (GFAP and BAX) staining and biochemical study for lactic dehydrogenase (LDH), superoxide dismutase (SOD), malondialdehyde (MDA) and glucose-6-phosphate-dehydrogenase (G6PDH). Also, isoenzyme electrophoresis of LDH, G6PDH and SOD were performed. The present study found that, seven-days BL exposure caused damage to both cornea and retina. However, after exposure to dim-light after bright light there was partial improvement in corneal and retinal structure and an increase in the assayed SOD and G6PDH levels, along with a reduction in MDA content and activity of LDH. These findings demonstrate a plasticity that may help C. gariepinus survive disturbances in the aquatic environment.

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DOI: 10.3897/zoologia.35.e24446

Authors: Mauricio Lang dos Santos, Valéria Marques Lemos, João P. Vieira

Abstract: We report on the interaction between common bottlenose dolphins, Tursiops truncatus (Montagu, 1821) and cast net fishermen in southern coast of Brazil. The fishery was monitored in the mouth of the Tramandaí River Estuary to investigate the seasonality of catches and their relationships with a set of variables: presence/absence and number of bottlenose dolphins, fishing area, temperature, salinity, wind and water flow direction in the channel. The mullet, Mugil liza Valenciennes, 1836 is the target species and was the dominant fish in the catches (77% of total catch; 50% in frequency; 0.2 ind. x f-1). The use of GLM models helped to reveal that the number of the bottlenose dolphins, time of year (months) and spatial variation of fishing activity were the main factors explaining the presence and abundance of mullet in the fishermen’s catches. The presences of bottlenose dolphins in the fishing area raise the probability of fishermen catch larger number of mullets with smaller fishing effort. However, the size of the mullet is influenced basically by seasonality. The mullets are the “currency” of bottlenose dolphins and fishermen interaction. There are reasons for concern about the sustainability of the southern Brazilian M. liza stock, once the decrease of this fishing resource can lead this rare and traditional fishery to the extinction.

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DOI: 10.3897/zoologia.35.e12906

Authors: Anita Studer, Marcelo Cardoso de Sousa, Begoña Barcena Goyena

Abstract: We present the results of a 26-year study on the breeding biology of the Short-tailed Antthrush, Chamaeza campanisona (Lichtenstein, 1823) in an Atlantic rainforest remnant of northeastern Brazil (Alagoas/Pernambuco). We followed the fate of 38 nests, of which 19 failed, 11 succeeded and 8 had an unknown fate. The presence of most nests coincided with the beginning of the rainy season in March/April but nests with eggs and/or chicks were found throughout the year, with no records only in January. Nests were placed inside natural tree cavities that result from broken branches and trunks. Both parents were engaged in feeding the chicks, their diet consisted mainly of insects, spiders, and some unidentified berries. All nests had a clutch size of two eggs. Incubation took 19 days and the mean nestling period was 20.75 days. Mayfield (1975) showed a survival rate of 31.87% and MARK 24.09%. Hotelling’s T2 revealed no differences in nest characteristics between successful and failed nests (p-value > 0.05). Linear models showed that the size of the entrance of the cavity and its height from ground are the main nest characteristics influencing the nesting success of C. campanisona.

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