Diel variation of fish community in sandy beaches of southeastern Brazil

Abstract

Fish living in coastal waters present behavior patterns ruled by environmental light levels. Diel variations in fish community structure were investigated at Arraial do Cabo surf zone (22º58'S, 42º01'W). From September/2001 to August/2002 monthly sampling consisted of 12 hauls of a beach seine during the day and at night at Praia dos Anjos, Praia Grande and Prainha beaches. Different temporal distribution patterns of the ichthyc community were recorded. At Praia dos Anjos, total richness was higher at night while the average number of species, CPUE, Margalef's richness and Shannon diversity were generally higher during the day. We believe that this pattern was caused by the displacement of some species such as Harengula clupeola,Trachinotus carolinus and Umbrina coroides at night to deeper areas searching for food or for predator avoidance. At Praia Grande and Prainha the average number of species, CPUE, richness and diversity indexes were generally higher at night with the dominant species H. clupeola, Pomatomus saltatrix and Sardinella brasiliensis. It is suggested that the main factor to diel variation is the protection against predators due to darkness, making visualization of the prey difficult, besides the presence of seasonal macroalgae beds at Prainha, which might function as a food area for piscivorous fishes due to the proximity of larger individuals in shallower water especially at night.

Juvenile fish use of the shallow zone of beaches of the Cananéia-Iguape coastal system, southeastern Brazil

“…Several studies of Brazilian beaches (GIANNINI; PAIVA FILHO, 1995;GODEFROID et al, 2003;VASCONCELLOS et al, 2007;GAELZER;ZALMON, 2008;FAVERO; and beaches elsewhere (MODDE, 1980;NASH, 1995;LAYMAN, 2000) indicate high abundance of juveniles of this genus in such habitats. However, information on the spawning sites and seasons remains sparse, which makes it difficult to interpret the Trachinotus recruitment pattern in the study area.…”

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.…”

“…Studies examining the natural variations in fish assemblages suggest that the daily movements of the ichthyofauna primarily follow their physiological and ecological needs, such as foraging, protection against predators and decreasing interspecific competition for food and space (Thijssen et al, 1974;Piet & Guruge, 1997;Suda et al, 2002;Pessanha et al, 2003;Gaelzer & Zalmon, 2008). The daily movements of the ichthyofauna within an assemblage have been described for several environments (Wright, 1989;Piet & Guruge, 1997;Rooker & Dennis, 1991;Nagelkerken et al, 2000;Pessanha et al, 2003;Galzer & Zalmon, 2008;Félix-Hackradt et al, 2010).…”

Feeding ecology of the beach silverside Atherinella blackburni (Atherinopsidae) in a tropical sandy beach, Southeastern Brazil

“…Moreover, it is possible that the difference observed in the diet composition is closely related to the population structure of A. blackburni in each period of the day. The predominance of small fish in the morning along with the predominant items in their diet might suggest that individuals of up to 30 mm feed in the surf zone during daytime, moving to deeper water at night in search for protection against predators (REEBS, 2002;GAELZER;ZALMON, 2008).…”