Temporal patterns of resource partitioning among Cichla species in a Venezuelan blackwater river

Abstract

In channel and floodplain habitats of the Cinaruco River, Venezuela, Cichla temensis was more abundant and larger than C. intermedia and C. orinocensis. Seasonal variation in hydrology influenced habitat use, spawning, and predator-prey interactions. The three piscivores partitioned habitat, with C. intermedia showing a strong affinity for structured habitats in the main channel during all water level fluctuations. C. orinocensis was most abundant in shallow areas with submerged structure in lagoons and, to a lesser extent, in low velocity regions of the channel, and C. temensis occupied a wide range of lotic and lentic habitats. During the low-water period, the feeding frequency and body condition of all three species declined, and this was related, in part, to preparation for spawning near the end of the low-water season. The diet of C. intermedia was least similar to its two congeners during falling and rising water. C. orinocensis and C. temensis had lowest diet overlap during the low-water conditions, the period when many individuals of these two species move into lagoons for nesting. Prey in stomachs were significantly larger during the falling-water than the rising-water period, and predation by Cichla and other large piscivores during the falling-water period may have reduced the abundance of large prey, particularly Semaprochilodus kneri. These migratory detritivorous fish were important prey for C. temensis during the falling-water period and probably contributed a substantial fraction of the annual energy intake for this species. Together, the three Cichla species consume a wide spectrum of prey from a diverse fish assemblage, but prey are subdivided based on habitat, prey type, and season.

Feeding habits of the congeneric species Stellifer rastrifer and Stellifer brasiliensis (Acanthopterygii: Sciaenidae) co-occurring in the coast of the state of Santa Catarina, Brazil

“…Although the most important items in the diet of these species are the same, the intake of each alternates in time, suggesting a difference in predation pressure, which leads to less direct competition in a given time. The coexistence of similar species within the same ecosystem may occur owing to different resource use, as resource partitioning includes food, habitat and/or time segregation (Pianka, 1973;Schoener, 1974), and seasonal fluctuations in food resource availability have been shown to modify resource partitioning among sympatric fish species (Jepsen et al, 1997).…”

Seasonal variation in fish trophic networks in two clear-water streams in the Central Llanos region, Venezuela

“…Higher piscivore relative abundance during the low-water period also could have been influenced by immigration of piscivorous fishes seeking to exploit prey that initially have high densities within shrinking aquatic habitat. With influx of piscivores, prey populations have higher predation mortality and population decline (Winemiller, 1989;Jepsen et al, 1997). Abundance of Hemigrammus spp.…”

O espaço e dinâmica sazonal na percepção de pescadores tradicionais da APA Maribús - Iraquara, Chapada Diamantina - BA

“…O tucunaré teria "colocado muito peixe pra correr" ou "metido medo" nas espécies nativas. é muito provável que o tucunaré esteja realmente provocando redução de populações nativas, uma vez que se trata de uma espécie reconhecidamente piscívora e agressiva (JEMPSEN et al, 1997 (BRandão, 1949;maRQueS, 1998;1999). marques (1999) salienta para um ambiente de várzea no Estado de Alagoas que, segundo a percepção local, algumas aves compõem, junto com outros animais, um conjunto de "bichos que aduvinham (sic.)…”