Zooplankton community resilience and aquatic environmental stability on aquaculture practices: a study using net cages

Dias, Juliana Déo; Simões, NR; Bonecker, Cláudia Cósta

doi:10.1590/s1519-69842012000100001

Cited by 13 publications

(11 citation statements)

References 41 publications

(41 reference statements)

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“…Aquaculture is associated with a number of impacts, chief among which are increased concentrations of nitrogenated compounds (Borges et al, 2010;Ansah et al, 2012), the introduction of exotic species (Naylor et al, 2000) and the destabilization of the trophic network (Borges et al, 2010;Dias et al, 2012b). Thus, in the Paranoá lake, a reduction in the biomass of farmed tilapia (from 900 to 350 kg.ha -1 ) lead to improvements in water quality due to a significant decrease in turbidity (-46%), total phosphorus concentration (-31%), microalgal blooms (-70%) and phytoplankton biomass (-38%) (Starling et al, 2002).…”

Section: Discussionmentioning

confidence: 99%

Limnological characteristics of a reservoir in semiarid Northeastern Brazil subject to intensive tilapia farming (Orechromis niloticus Linnaeus, 1758)

Bezerra

Paulino²,

Garcez

et al. 2014

Acta Limnol. Bras.

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AIM: There is currently no consensus regarding the physical and chemical variability of tropical reservoirs. In semiarid Northeastern Brazil, reservoirs are among other things used for human consumption, industrial water supply and intensive fish farming, all of which can impact water quality. The objective of this study was to evaluate the physical and chemical variability of the water in Sítios Novos, a reservoir in semiarid Northeastern Brazil, comparing samples collected in areas of intensive tilapia (Oreochromis niloticus) farming to samples from areas not directly impacted by aquaculture, in both the dry and the rainy season. METHODS: Between October 2010 and July 2011, data were collected on temperature, conductivity, pH, turbidity, salinity, chlorophyll a, dissolved oxygen, oxygen demand, total phosphorus and total nitrogen levels in the water column using a multiparametric probe at four different sampling locations. Physical and chemical differences between the four locations were evaluated with the Kruskal-Wallis (KW) test and Dunn's post test, while the t test, followed by Welchʼs correction, was used to compare samples collected in different seasons. RESULTS: No influence of intensive aquaculture was detected when comparing sampling locations near fish farms (180C and 300C) to locations not directly impacted by aquaculture (LIMN1, near the dam, and LIMN2, near the debouch of the São Gonçalo river). However, the sampling locations differed significantly (p<0.05) with regard to conductivity, pH, turbidity and chlorophyll a levels. CONCLUSIONS: The physical and chemical variability was greater between seasons than between locations when the data were analyzed with the t test. That analysis showed significant differences for 22 of 40 comparisons between the 10 physical and chemical parameters in the two seasons at the four sampling locations. In conclusion, the physical and chemical variability registered for the Sítios Novos reservoir throughout the study period indicates morphometric, meteorological and hydrological heterogeneity, with emphasis on the differences between LIMN2 and the other three sampling locations and between the rainy season and the dry season. According to the calculated trophic status index, the reservoir is supereutrophic in the rainy season and supereutrophic to hypereutrophic in the dry season.

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Section: Discussionmentioning

confidence: 99%

Limnological characteristics of a reservoir in semiarid Northeastern Brazil subject to intensive tilapia farming (Orechromis niloticus Linnaeus, 1758)

Bezerra

Paulino²,

Garcez

et al. 2014

Acta Limnol. Bras.

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“…Special attention must be paid to cyanobacteria blooms, which are symptomatic of eutrophication in productive lakes, since they may produce cyanotoxins (Funari and Testai, 2008;Semyalo et al, 2010) which are toxic to vertebrates and can affect human health through direct contact or consumption of contaminated water, fish or plants. Caging aquaculture may also cause other impacts on aquatic environments, such as the destruction of natural habitats and alterations in the structure and dynamics of local organisms, as well as trophic changes (Agostinho et al, 2008;Strictar-Pereira et al, 2010;Dias et al, 2012).…”

Section: Introductionmentioning

confidence: 99%

The influence of fish culture in floating net cages on microbial indicators of water quality

et al. 2013

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This work was carried out to analyse the microbiological parameters of the water quality of a reservoir used for the irrigation and culture of tilapia (Oreochromis niloticus) in floating net cages. The physico-chemical parameters, counts of mesophilic total aerobic bacteria, total and thermotolerant coliforms and fecal streptococci, and the presence of Escherichia coli in samples of water collected in three sites of the reservoir (pre-culture site, culture site, post-culture site) were analysed. The levels of ammonia (0.047-0.059 mg/L), nitrite (0.001-0.021 mg/L) and total phosphorus (0.050-0.355 mg/L) in the water did not show significant differences (p > 0.05) between sampling sites. The levels of total bacteria in the water varied between 1.3 x 10 4 and 67.3 x 10 4 CFU/100 mL. The MPN values of thermotolerant coliforms (< 930 MPN/100 mL) were within values recommended for water used for fish culture and/or irrigation. The presence of E. coli and fecal streptococci were verified in 48% and 56% of analysed samples, respectively. The site with floating net cages showed more samples contaminated with E. coli and fecal streptococci than other sampling points.Keywords: fish culture, tilapia, cage, coliforms, faecal streptococci. Influência da piscicultura em tanques-rede sobre os microrganismos indicadores da qualidade de água ResumoEste trabalho foi realizado para analisar os parâmetros microbiológicos da qualidade da água de um reservatório destinado a irrigação e à cultivo de tilapia do Nilo (Oreochromis niloticus) em tanques redes. Foi realizada análise de parâmetros físico-químicos, quantificação de bactérias totais aeróbias mesófilas, coliformes totais e termotolerantes, estreptococos fecais e a detecção de E. coli em amostras de água coletada em três pontos distintos do açude (pré-cultivo, cultivo, pós-cultivo). Os níveis de amônia (0,047-0,059 mg/L), nitrito (0,001-0,021 mg/L) e fósforo total (0,050-0,355 mg/L) na água não apresentaram diferenças significativas (p > 0.05) entre os pontos de coleta. As contagens de bactérias aeróbias mesófilas variaram entre 1,3 x 10 4 e 67,3 x 10 4 UFC/100 mL nas amostras de água. O NMP de coliformes termotolerantes (< 930 NMP/100 mL) se apresentou dentro do limite permitido para águas doces destinadas a piscicultura e/ou irrigação. A presença de E. coli foi constatada em 48% e de estreptococos fecais em 56% das amostras de água analisadas. O local de cultivo de tilápia em tanques-rede apresentou maior número de amostras contaminadas com E. coli e estreptococos fecais que outros pontos de amostragem.

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“…According to the PCA results and alterations in community abundance, as evidenced by the ANOVA results, there is a high primary production and changes in the system productivity, revealing alterations in community abundance, influencing its stability (Sommer et al, 1986;Tilman et al, 2006). In addition, the increase in productivity increases rates of individual growth and reproduction of organisms, and thereafter, the rapid increase in population abundance (Gliwicz, 2002;Dias et al, 2012). Those results were revealed through the negative association with phosphorus and the positive with nitrogen -major environmental variables related to productivity.…”

Section: Discussionmentioning

confidence: 99%

Effects of nutrients increase on the copepod community of a reservoir using cages

et al. 2015

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Aim: This study investigated changes in copepod abundance and the influence of environmental variables in a reservoir with fish farming using cages, on temporal and spatial scales. We hypothesised that the copepod abundance will increase when influenced by changes in environmental variables due the increase of nutrients originating from fish farming. Methods A 120-day sampling of copepods and environmental variables was carried out in a subtropical reservoir of the Paraná River basin (Rosana reservoir), upstream and downstream of three sets of cages with different fish stocking densities. A Principal Component Analysis was conducted to characterise sampling periods and points through environmental variables. The differences between copepod abundance according to sampling periods and points were tested by ANOVA. Results We observed higher maximum values for most nutrient concentrations and dissolved oxygen in the final stage of the experiment and in the location of cages installation. The copepod abundance increased sharply during the first days of the experiment and then decreased during the following periods with a tendency towards returning to the initial conditions at the final stage of the experiment. A significant difference in copepod abundance between the location of cages installation and downstream was showed. In addition, turbidity, chlorophyll-a, and nitrate significantly predicted copepod abundance. Conclusion The results suggested that the changes in copepod abundance over time are influenced by environmental variables, evidenced by the increase in nutrient concentration after the cage installation, related to the increase in the practice of fish farming. The environmental variables related to system productivity were linked to the availability of food resources. Thus, our hypothesis that copepod abundance is increased due the alterations in environmental variables caused by the increase in the practice of fish farming using cages was corroborated.

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Zooplankton community resilience and aquatic environmental stability on aquaculture practices: a study using net cages

Cited by 13 publications

References 41 publications

Limnological characteristics of a reservoir in semiarid Northeastern Brazil subject to intensive tilapia farming (Orechromis niloticus Linnaeus, 1758)

Limnological characteristics of a reservoir in semiarid Northeastern Brazil subject to intensive tilapia farming (Orechromis niloticus Linnaeus, 1758)

The influence of fish culture in floating net cages on microbial indicators of water quality

Effects of nutrients increase on the copepod community of a reservoir using cages

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