Diel seasonality in fish biodiversity in a sandy beach in south-eastern Brazil

Abstract

Diel fluctuations in nearshore fish communities were studied at a sandy beach in south-eastern Brazil. A total of 192 samples were performed by beach seines, during 3-hour intervals throughout 48-hour periods, between spring 2005 and winter 2006. Mean biomass and number of species were significantly higher at night, while number of individuals did not differ between day and night. Major disruptions in the fish community occurred during the winter when the assemblages underwent restructuring. Harengula clupeola, Sardinella janeiro, Anchoa lyoleps and Umbrina coroides were the predominant species at night, while Atherinella brasiliensis, Pomatomus saltatrix and Trachinotus carolinus peaked during the day, although significant diel changes in community structure were recorded only in the summer. Biological interactions, behavioural variations and local constraints might explain diel differences in the fish distribution. This study confirms that changes in diel activity in juvenile fish species can differ in similar areas, even for a given species, and the causes of these changes needs to be investigated.

Comparison of the temporal and taxonomic patterns of ichthyofauna captured with a fyke net in two sheltered environments in southern Brazil

“…In shallow environments, the use of relatively small trawls and low sampling speeds is common (Pessanha et al, 2003;Gaelzer & Zalmon, 2008;Félix-Hackdart et al, 2010;Vasconcellos et al, 2010). However, this equipment is apparently not very effective in capturing individuals that respond rapidly to the net's visual and mechanical stimuli (Glass & Wardle, 1989;Methven et al, 2001;Gell & Whittington, 2002), generally resulting in an underestimation of the richness of the local ichthyofauna which can have greater or lesser importance for future handling and management decisions.…”

Spatial and temporal distribution patterns of the silver mojarra Eucinostomus argenteus (Perciformes: Gerreidae) in a tropical semi‐enclosed bay

“…Knowledge about the main components of the estuarine and coastal communities and their interaction with the environment is essential to understand the ecological function and status of these ecosystems and help propose sound management policies to mitigate adverse environmental effects (Blaber, ; Barletta et al ., ; Nicolas et al ., ). Despite the environmental threats and its great economic and ecological importance, however, few studies have investigated the ecological aspects of the fish fauna from Guanabara Bay (Rodrigues et al ., ; Andrade‐Tubino et al ., ; Vasconcellos et al ., ; Silva Junior et al ., ).…”

Diel Variations and Ecological Aspects in Fish Assemblages of a Sandy Beach in the Semi-Arid Region of Northeast Brazil.

“…Thus, its high density during the day may have been favored by the presence of light, as observed in Trachinotus carolinus (Linnaeus, 1766) in Guanabara Bay (Rio de Janeiro, Brazil) during the day (Vasconcelos et al, 2010). Length differences among sampled individuals during the day and at night can be attributed to the nocturnal habits of adult fish, which are less numerous and sociable, but are greater in size and biomass (Vasconcellos et al, 2010). However, only Pomadasys corvinaeformis and Bagre marinus presented statistically higher lengths at night compared to the diurnal period.…”

“…This result substantiates that the dissimilarity occurred mainly due to the influence of these six species densities. Besides, diel activities of fish species, especially juveniles, may differ from one area to another, even for a given species (Vasconcellos et al, 2010). Thus, the possible causes of such changes require further investigation.…”