Spatial and temporal distribution of larvae and juveniles of Hoplias aff. malabaricus (Characiformes, Erythrinidae) in the Upper Paraná River floodplain, Brazil

Abstract

Spatial and temporal distribution of larvae and juveniles of trahira, Hoplias aff. malabaricus (Erythrinidae), and their relationship with environmental parameters in the Upper Paraná River floodplain were analyzed. Sampling of larvae and juveniles of H. aff. malabaricus has been conducted during the period from November 1991 through February 1995, with 42 sampling stations distributed in four sub-areas: Ivinhema I, Ivinhema II, Baía, and Paraná. During the same period, data were obtained for water temperature, dissolved oxygen, pH, electrical conductivity, river level, precipitation index, and photoperiod. The largest catches of larvae were in the Ivinhema I sub-area (47.06%), and of juveniles in the Paraná sub-area (54.55%). Larvae and juveniles were caught from October to February. Larvae were mainly collected at night and in all types of environments sampled (lotic, semi-lotic, and lentic). Principal Component Analysis of the environmental parameters and larval density showed that the largest catches were obtained in dry season months, with low values for temperature, electrical conductivity, river level, and photoperiod, and with high concentrations of dissolved oxygen and pH. This reproductive strategy may minimizes predation and maximizes food utilization, as it enables the fish to reach advanced developmental stages, while most other species are spawning.

Fish larvae assemblages in two floodplain lakes with different degrees of connection to the Paraná River, Brazil

“…Water temperature is one of the most important factors in the fish life cycle and can speed up or delay metabolic processes. The relationship between larval occurrence and high temperatures has also been documented in other environments in the Paraná River by several authors Cavicchioli et al, 1997;Bialetzki et al, 2002). The greatest reproductive intensity of most fish species in the upper Paraná River occurs between October and February (Vazzoler, 1996), when water temperatures are highest.…”

Uso de recursos alimentares por peixes imaturos e adultos de espécies piscívoras em uma planície de inundação neotropical

“…Assim como a traíra, P. corruscans apresentou canibalismo, também evidenciado por Beux & Zaniboni Filho (2007). A curvina, P. squamosissimus possui boca grande terminal (Bialetzki et al 2002) bastante protrátil o que possivelmente facilita a captura de presas em locais de difícil acesso para a maioria dos outros piscívoros. No presente estudo, a dieta dessa espécie foi a que mais diferiu dos outros predadores, pelo fato de curvinas imaturas, terem consumido uma proporção expressiva do camarão Macrobrachium amazonicum, um recurso muito abundante na planície de inundação (Bialetzki et al 1997).…”

Species of the Hoplias aff malabaricus complex (Characiformes: Erythrinidae): An investigation of coexistence in a Neotropical floodplain

“…According to BIALETZKI et al (2002), thraira reproduce in the period prior to the flood season, which allows the larvae to reach later stages of development while most of the other trophic guilds have not yet spawned, minimizing predation and maximizing their use of available resources, with consequent improvement in offspring survival. IKEZIRI et al (2008) observe the same strategy in several piscivorous species in the Amazon region.…”

“…malabaricus complex exhibits a wide geographical distribution (GERY 1977, BARBIERI et al 1982, MELLO et al 2006, VICARI et al 2006) and is commonly found in the biotopes of the Upper Paraná River floodplain (BIALETZKI et al 2002), where this complex is important among piscivorous fish species with a high contribution to both number and biomass (LUIZ et al 2004). PETRY et al (2007), analysing the complex as a single species, verified its key role in the Upper Paraná River floodplain in structuring assemblages of fish in isolated lagoons.…”