In visual predation, fish spot and capture the food, eating it directly ( Lazzaro 1987 Lazzaro X (1987) A review of planktivorous fishes: their evolution, feeding, behaviours, selectivities and impacts. Journal of Experimental Biology 199: 1743-1756., Zavala-Camin 1996 Zavala-Camin LA (1996) Introdução aos estudos sobre alimentação natural em peixes. 1996 Sanderson SL, Stebar MC, Ackermann KL, Jones SH, Batjakas IE, Kaufman L (1996) Mucus entrapment of particles by a suspension-feeding tilapia (Pisces: Cichlidae). In filter feeding, mucus is secreted in the gill rakers, allowing the fish to retain planktonic organisms ( Lazzaro 1987 Lazzaro X (1987) A review of planktivorous fishes: their evolution, feeding, behaviours, selectivities and impacts.
In: Beveridge MCM, McAndrew BJ (Eds.) Tilapias: Biology and Exploitation. It is a filter feeder that also uses visual predation ( Beveridge & Baird 2000 Beveridge MCM, Baird DJ (2000) Diet, feeding and digestive physiology, p. ) that has been introduced in several countries, being cultured worldwide. 2007 Attayde JL, Okun N, Brasil J, Menezes RF, Mesquita P (2007) Impactos da introdução da tilápia do Nilo, Oreochromis niloticus, sobre a estrutura trófica dos ecossistemas aquáticos do Bioma Caatinga. The Nile Tilapia, Oreochromis niloticus (Linnaeus, 1758), is a plankton-feeding omnivorous species native to Africa ( Attayde et al. The increase in the size of the Nile tilapia's gill raker does not determine the consumption of larger zooplankton prey, and the presence of mucus in these structures plays a major role for the capture of zooplankton during the cichlid's adult stage.įiltration microcrustaceans predation rotifers However, when adults, filter-feeding plays a more important role in the way the zooplankton community is affected. Juvenile Nile tilapia filter feed and visually prey on zooplankton. As adults, fish stop preying visually and the mucus secreted by the gill rakers trap only small individuals. Juveniles filter feed on rotifers, and actively prey on microcrustaceans. Therefore, negative correlations were found between raker size and size of ingested zooplankton, showing that the size of ingested prey decreases throughout this cichlid's life. The gill raker size, nevertheless, increased as tilapia grew. Fish increased consumption of rotifers, and decreased the consumption of microcrustaceans considerably up to zero in the last month. Stomach contents and gills of fish were extracted, fixed in formaldehyde and then analyzed with an optical microscope and stereomicroscope with a micrometric ocular in order to measure the zooplankton and the gill rakers. We randomly removed one fish per pond every month. We evaluated the diet of Nile tilapia kept in ponds for four months.
niloticus at the post-larval stage, and if the way they capture food may determine prey size. The objective in this study was to verify which zooplankton groups contribute to the diet of O. At different ontogenetic stages, the Nile tilapia may impact the zooplankton community differently, since it changes how it captures its prey. In visual predation, the fish spot and capture food, eating it directly. In filter feeding, the mucus secreted in their gill rakers traps planktonic organisms. The Nile tilapia, Oreochromis niloticus (Linnaeus, 1758), uses filter feeding and visual predation to catch prey.
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