Effects of the flood regime on the body condition of fish of different trophic guilds in the Upper Paraná River floodplain, Brazil
In this study, we evaluated the influence of various hydrological cycles on the feeding body condition of fish species of different trophic guilds in the Paraná River floodplain, as well as the impacts of upstream impoundments on fish conditions. Attributes of the river floods (duration, time of yea...
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| Format: | Article |
| Language: | English |
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Instituto Internacional de Ecologia
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| Series: | Brazilian Journal of Biology |
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| Online Access: | http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1519-69842009000300003&lng=en&tlng=en |
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| author | F. Abujanra AA. Agostinho NS. Hahn |
| author_facet | F. Abujanra AA. Agostinho NS. Hahn |
| author_sort | F. Abujanra |
| collection | DOAJ |
| description | In this study, we evaluated the influence of various hydrological cycles on the feeding body condition of fish species of different trophic guilds in the Paraná River floodplain, as well as the impacts of upstream impoundments on fish conditions. Attributes of the river floods (duration, time of year, intensity, and variability in a given year) and the body condition, measured by the mean residuals of length-weight ratios, of the detritivorous, herbivorous, insectivorous, invertivores, omnivorous, piscivorous, and planktivorous species were evaluated. Fish were sampled during a period before (1986-1994) and after (2000-2004) the completion of filling of the Porto Primavera Reservoir, which is located upstream from the floodplain area under study. Three sub-basins in the floodplain were sampled: the Ivinheima River, which has no dams; the Paraná River, which has several dams; and the Baia River, which is influenced by the Paraná. A two-way ANOVA identified significant variations in mean body conditions for localities and for the hydrological cycles, and the interactions were also significant. The findings revealed that before the Porto Primavera Reservoir was filled, the body condition of the feeding guilds varied similarly in the three sub basins, but this pattern was not observed after filling was completed. However, in years with minor or no floods, the body condition was high, especially in the sub-basins influenced by Porto Primavera (Paraná and Baía). Pearson's and Spearman's correlations showed that most effects of the floods were unfavorable to the body condition of the guilds, except for the annual variation in water level, which aids herbivores in accessing allochthonous food resources. Detritivores were negatively affected by all flood attributes. A correlation between the relative stomach weight (mean residual of the ratio of total and stomach weights) and the body condition demonstrated the poor relationship between the amount of food intake and weight gain; insectivores were the exception, showing a significant negative correlation. Therefore, for this guild, there is evidence that their food sources during floods have low nutritional value. It is hypothesized that dry years lead to improvement in the nutritional quality of food resources, and that the water released from the upstream dam dilutes and removes these resources without providing new food inputs. This exacerbates the effects of floods on body conditions. |
| first_indexed | 2024-12-13T18:08:34Z |
| format | Article |
| id | doaj.art-5b2fa7c412514ca2b68622e2e6ef725e |
| institution | Directory Open Access Journal |
| issn | 1678-4375 |
| language | English |
| last_indexed | 2024-12-13T18:08:34Z |
| publisher | Instituto Internacional de Ecologia |
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| series | Brazilian Journal of Biology |
| spelling | doaj.art-5b2fa7c412514ca2b68622e2e6ef725e2022-12-21T23:36:01ZengInstituto Internacional de EcologiaBrazilian Journal of Biology1678-4375692 suppl46947910.1590/S1519-69842009000300003S1519-69842009000300003Effects of the flood regime on the body condition of fish of different trophic guilds in the Upper Paraná River floodplain, BrazilF. Abujanra0AA. Agostinho1NS. Hahn2Universidade Estadual de MaringáUniversidade Estadual de MaringáUniversidade Estadual de MaringáIn this study, we evaluated the influence of various hydrological cycles on the feeding body condition of fish species of different trophic guilds in the Paraná River floodplain, as well as the impacts of upstream impoundments on fish conditions. Attributes of the river floods (duration, time of year, intensity, and variability in a given year) and the body condition, measured by the mean residuals of length-weight ratios, of the detritivorous, herbivorous, insectivorous, invertivores, omnivorous, piscivorous, and planktivorous species were evaluated. Fish were sampled during a period before (1986-1994) and after (2000-2004) the completion of filling of the Porto Primavera Reservoir, which is located upstream from the floodplain area under study. Three sub-basins in the floodplain were sampled: the Ivinheima River, which has no dams; the Paraná River, which has several dams; and the Baia River, which is influenced by the Paraná. A two-way ANOVA identified significant variations in mean body conditions for localities and for the hydrological cycles, and the interactions were also significant. The findings revealed that before the Porto Primavera Reservoir was filled, the body condition of the feeding guilds varied similarly in the three sub basins, but this pattern was not observed after filling was completed. However, in years with minor or no floods, the body condition was high, especially in the sub-basins influenced by Porto Primavera (Paraná and Baía). Pearson's and Spearman's correlations showed that most effects of the floods were unfavorable to the body condition of the guilds, except for the annual variation in water level, which aids herbivores in accessing allochthonous food resources. Detritivores were negatively affected by all flood attributes. A correlation between the relative stomach weight (mean residual of the ratio of total and stomach weights) and the body condition demonstrated the poor relationship between the amount of food intake and weight gain; insectivores were the exception, showing a significant negative correlation. Therefore, for this guild, there is evidence that their food sources during floods have low nutritional value. It is hypothesized that dry years lead to improvement in the nutritional quality of food resources, and that the water released from the upstream dam dilutes and removes these resources without providing new food inputs. This exacerbates the effects of floods on body conditions.http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1519-69842009000300003&lng=en&tlng=encondition factornutritional conditionflood pulsesfloodplainregulated rivers |
| spellingShingle | F. Abujanra AA. Agostinho NS. Hahn Effects of the flood regime on the body condition of fish of different trophic guilds in the Upper Paraná River floodplain, Brazil Brazilian Journal of Biology condition factor nutritional condition flood pulses floodplain regulated rivers |
| title | Effects of the flood regime on the body condition of fish of different trophic guilds in the Upper Paraná River floodplain, Brazil |
| title_full | Effects of the flood regime on the body condition of fish of different trophic guilds in the Upper Paraná River floodplain, Brazil |
| title_fullStr | Effects of the flood regime on the body condition of fish of different trophic guilds in the Upper Paraná River floodplain, Brazil |
| title_full_unstemmed | Effects of the flood regime on the body condition of fish of different trophic guilds in the Upper Paraná River floodplain, Brazil |
| title_short | Effects of the flood regime on the body condition of fish of different trophic guilds in the Upper Paraná River floodplain, Brazil |
| title_sort | effects of the flood regime on the body condition of fish of different trophic guilds in the upper parana river floodplain brazil |
| topic | condition factor nutritional condition flood pulses floodplain regulated rivers |
| url | http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1519-69842009000300003&lng=en&tlng=en |
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