Conteúdo energético de peixes do reservatório do rio Manso: variações espaciais e por grupo trófico

2010

Neotrop. ichthyol.

The present study described the variations in energy density from skeletal muscles of Loricariichthys platymetopon in relation to body size, sex, gonadal development stages, sampling site and habitat type (lotic, semi-lotic and lotic). Samplings were performed between June 2002 and August 2006 in points located in the upper Paraná River floodplain, Rosana Reservoir and Diamante Stream. The energy density from each muscle sample of 212 specimens was determined using an adiabatic calorimeter. The correlations between the variables 'muscle energy density' and 'specimen standard length' were not significant. Only in the Rosana Reservoir there was a significant difference in energetic means between 'sex'. Otherwise, due to the gonadal development stage, a significant difference between energetic means was recorded only for males from the upper Paraná River floodplain and for both sexes in Rosana Reservoir. The density of muscle energy ranged from 4,170 to 5,540 cal/g DW (dry weight), with the means (± standard deviation) of 5,140± 0.06 cal/g DW in the Reservoir, 4,950±0.25 cal/g DW in the stream and 4,920 ±0.18 cal/g DW in the floodplain. Furthermore, we also detected a significant difference between the energy means from the different sampled sites, but the same was not registered among the analyzed habitats. In conclusion, the variation in muscle energy density from L. platymetopon may occur. The occurrence of variation between the sexes depends on the site, and the density variation among the stages depends on both the site and 'sex'. In summary, the spatial variation in muscle energy density from this species strengthens the idea that this factor is not a constant parameter, so it should not be applied in bioenergetics modeling and in the quantification of energetic balance as an unique value.O presente estudo objetivou descrever as variações na densidade de energia dos músculos estriados esqueléticos de Loricariichthys platymetopon em relação aos fatores tamanho, sexo, estádio de desenvolvimento gonadal, local e tipo de habitat (lótico, semi-lótico e lótico). As amostragens foram realizadas entre junho de 2002 e agosto de 2006 em pontos localizados na planície alagável do alto rio Paraná, no reservatório de Rosana e no ribeirão Diamante. A densidade de energia de cada amostra de músculo de 212 espécimes de L. platymetopon foi determinada utilizando-se bomba calorimétrica. As correlações entre as variáveis 'densidade de energia muscular' e 'comprimento padrão do espécime' não foram significativas. Diferença significativa entre as médias energéticas foi registrada entre 'sexo' apenas no reservatório de Rosana. Diferença nas médias energéticas, devido ao estádio de desenvolvimento gonadal, foi significativa somente para machos na planície alagável do alto rio Paraná e para ambos os sexos no reservatório de Rosana. A densidade de energia muscular variou de 4.170 a 5.540 cal/g PS (peso seco), sendo as médias (± desvio-padrão) igual a 5.140± 0,06 cal/g PS no reservatório, 4.950±0,25 cal/g PS no ribeirão e 4.920 ±0,18 ...

Section: Discussionmentioning

confidence: 63%

Variation in energy density of Loricariichthys platymetopon (Siluriformes: Loricariidae) in the upper Paraná River basin

Garcia

2010

Neotrop. ichthyol.

“…In Manso reservoir this variation was also observed in neotropical species Serrassalmus maculatus, but not in Leporinus friderici, Acestrorhynchus pantaneiro, Schizodon borelli and Serrassalmus marginatus (Santana et al, 2005;Santos et al, 2006). Studies conducted with fish species from temperate regions indicate that the sites with greater food availability, higher energy content of food resources and lower intraspecific competition for those resources, tend to feature the individuals with better body energy conditions, that is, with higher caloric density.…”

Section: Discussionmentioning

confidence: 89%

Caloric density of Loricariichthys platymetopon (Osteichthyes, Loricariidae) in the Upper Paraná River floodplain, Brazil

Garcia

Braz. arch. biol. technol.

Takeda

2010

This study analyzed the muscle energy content (caloric density) of L. platymetopon captured at different sites of the Upper Paraná River floodplain, and potential relationships between the content and various environmental variables (water temperature, oxygen dissolved in water, food availability, relative numeric abundance) and biological variables (body size and reproductive cycle). Quarterly samplings from September 2006 to

“…Several others studies have stressed the importance of energy measures for the understand- ing of the dynamics of aquatic ecosystems (GOLLEY, 1961;CUMMINS and WUYCHECK, 1971; DRIVER et al, 1974;SALONEN et al, 1976;CLARKE et al, 1985;DAUVIN and JONCOURT, 1989;BEUKEMA, 1997;DOYLE et al, 2007). Nevertheless, even in well-studied temperate regions, the knowledge of the caloric content is still incomplete for many organisms (DOYLE et al, 2007).In Neotropical aquatic ecosystems, few studies have thus far investigated the caloric content, so data on the energy content of organisms in these ecosystems is even more scarce and mostly restricted to ichthyofauna (NGAN et al, 1993;DORIA and ANDRIAN, 1997;BENEDITO-CECILIO et al, 2004;SANTANA et al, 2005;ESPÍNOLA et al, 2008), aquatic macrophytes (ESTEVES and THOMAZ, 1990;DOURADO et al, 2004;LOPES et al, 2006) and a few invertebrate groups (HIGUTI et al, 2003;BAGATINI et al, 2007). Therefore, additional studies on invertebrates will contribute to the better understanding of the energy flow in neotropical ecosystems, as aquatic invertebrates play an important role in the trophic dynamics of freshwater ecosystems, mainly through their function of recycling nutrients and detritus (HENRY and SANTOS, 2008).…”

mentioning

confidence: 99%

Effect of the Environmental Factors on the Caloric Content of Benthic and Phytophilous Invertebrates in Neotropical Reservoirs in the Paraná State, Brazil

Bagatini

International Review of Hydrobiology

Higuti

2010

The complexity of the relations between the organisms and the environment are reflected through the energy content. So we tested the hypothesis on body energy content variation in invertebrates and its relation with some environmental factors (season, habitat type, trophic status and trophic guild). We expected higher energy values for phytophilous fauna, rainy season, in reservoirs with higher trophic levels and for herbivorous invertebrates. The results showed the influence of seasonality and trophic status of the reservoir on the energy content of invertebrates, which was higher in the rainy season and in the mesotrophic reservoirs, due to the input of allochthonous material during this season, confirming our initial prediction. A higher caloric content was recorded for carnivorous and detritivorous invertebrates. The differences between the trophic guilds were primarily related to the opportunistic feeding behavior, which may be considered as one of the main factors controlling the energy flow of benthic and phytophilous invertebrates. IntroductionThe energy dynamics in aquatic ecosystems can be better understood by studying the caloric content of the organisms (MUNN and BRUSVEN, 1991). However, the small size of aquatic invertebrates is often a problem for obtaining energy measurements, mainly due to the difficulty of sampling a large number of small specimens needed for calorimeter measurements (FELLER and WARWICK, 1988;LUCAS, 1992). Several studies have improved the knowledge on the energy content of several organisms.Since the pioneer work of LINDEMAN`s (1942) about the energy availability and trophic chains, several research projects were carried out in aquatic marine and freshwater ecosystems of temperate regions. A study performed by WISSING and HASSLER (1971) in freshwater ecosystems showed that the caloric values of invertebrates were related to seasonal variations. For example, the energetic content of Chironomidae was higher in the summer, because this is the growing season and quickly declined in the winter. STANCZYKOWSKA and LAWACZ (1976) also recorded higher energy value of Dreissena polymorpha in summer. Several others studies have stressed the importance of energy measures for the understand- ing of the dynamics of aquatic ecosystems (GOLLEY, 1961;CUMMINS and WUYCHECK, 1971; DRIVER et al., 1974;SALONEN et al., 1976;CLARKE et al., 1985;DAUVIN and JONCOURT, 1989;BEUKEMA, 1997;DOYLE et al., 2007). Nevertheless, even in well-studied temperate regions, the knowledge of the caloric content is still incomplete for many organisms (DOYLE et al., 2007).In Neotropical aquatic ecosystems, few studies have thus far investigated the caloric content, so data on the energy content of organisms in these ecosystems is even more scarce and mostly restricted to ichthyofauna (NGAN et al., 1993;DORIA and ANDRIAN, 1997;BENEDITO-CECILIO et al., 2004;SANTANA et al., 2005;ESPÍNOLA et al., 2008), aquatic macrophytes (ESTEVES and THOMAZ, 1990;DOURADO et al., 2004;LOPES et al., 2006) and a few invertebrate group...