Influence of fish cage farming on water quality and plankton in fish ponds: A case study in the Rift Valley and North Shoa reservoirs, Ethiopia

Degefu, Fasil; Mengistu, Seyoum; Schagerl, Michael

doi:10.1016/j.aquaculture.2011.03.010

Cited by 69 publications

(43 citation statements)

References 25 publications

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“…The present findings are corroborated by results reported by Degefu et al (2011), Mette et al (2011), Ssanyu et al (2011) and Shahabuddin et al (2012). The results further showed statistically comparable phytoplankton biomass and abundance between the ponds under MI and RB treatments.…”

Section: Discussionsupporting

confidence: 93%

Supplemental effects of mixed ingredients and rice bran on the growth performance, survival and yield of Nile tilapia, Oreochromis niloticus reared in fertilized earthen ponds

et al. 2016

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Unaffordability of commercial feeds to semi-intensive Nile tilapia, Oreochromis niloticus farmers has led to reliance on supplemental feeding and fertilization for nutrition of their fish without a scientific basis. This study compared the growth, survival, condition factor and yield performance of O.niloticus fed on mixed ingredients (MI) and rice bran alone (RB) diets reared in fertilized earthen ponds in small scale farmers’ ponds. The study also determined phytoplankton composition, biomass and abundance in the experimental ponds. Quadruplicate ponds were stocked with O. niloticus and African sharptooth catfish, Clarias gariepinus at a stocking ratio of 1:3. The initial mean weights of O. niloticus and C. gariepinus were 14.62 ± 0.61 and 20.34 ± 1.44 g respectively. The fish were fed on MI and RB diets with protein content of 184.74 and 126.06 g kg−1 respectively for 270 days. The results showed that growth performance, survival rate and condition factor of O.niloticus were not affected by either feeding with MI or RB diet (p > 0.05). Moreover, there were no significant differences obtained in phytoplankton biomass and abundance in O.niloticus ponds fed on the two diets (p > 0.05). Furthermore, feeding O.niloticus either on MI or RB diet did not affect the net and gross fish yields (p > 0.05). The study revealed that the use of either MI or RB diet does not significantly affect the performance of O.niloticus cultured in semi-intensive earthen ponds where natural food organisms are an integral part of the culture system. Rice bran could be used for semi-intensive culture of O.niloticus in fertilized ponds to boost the production based on its availability and low cost.

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Section: Discussionsupporting

confidence: 93%

Supplemental effects of mixed ingredients and rice bran on the growth performance, survival and yield of Nile tilapia, Oreochromis niloticus reared in fertilized earthen ponds

et al. 2016

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“…Cyanobacteria was probably favored by high temperatures, as also verified by Chu et al (2007), Degefu et al (2011) andKosten et al (2012). In spite of Cyanobacteria being a common component of the phytoplankton, it represents one of the main contributor to the biomass and diversity in aquatic ecosystems, especially in eutrophic waters (Sant'Anna et al, 2006a;Borges et al, 2008) and several species are potential toxin producers (Komárek, 2003;Calijuri et al, 2006).…”

Section: Discussionmentioning

confidence: 98%

Influence of fish farming in net cages on phytoplankton structure: a case study in a subtropical Brazilian reservoir

2014

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This study investigated the enrichment influence due to fish farming in net cages on the phytoplankton composition, density and diversity in two arms of a subtropical reservoir (Salto Caxias, Paraná). There were no statistically significant differences in the phytoplankton composition and diversity, as well as for concentrations of nutrients among the handled treatment. The density values were higher during the summer. Richness and Shannon diversity values were low during the study period. The equitability values were high during the winter and low in the summer. Variations of phytoplankton community and nutrients were mainly influenced by seasonality. The absence of significant differences between the treatments was probably due to the small number of net cages and fish used, as well as to the hydrodynamics of the studied environments, which are influenced by upstream rivers inflows.Keywords: phytoplankton, community structure, net cages, hydrodynamics's effect.Influência do cultivo de peixes em tanques-rede sobre a estrutura do fitoplâncton: estudo de caso em um reservatório subtropical brasileiro ResumoEste estudo investigou os efeitos do enriquecimento devido ao cultivo de peixes em tanques-rede sobre a composição, densidade e diversidade fitoplanctônica em dois braços de um reservatório subtropical (Salto Caxias, Paraná). Não foram registradas diferenças significativas para a composição e diversidade fitoplanctônica e para as concentrações de nutrientes entre os tratamentos utilizados. A densidade foi maior durante o verão. Os valores de riqueza de espécies e diversidade de Shannon foram baixos durante todo o período de estudo. A equitabilidade foi elevada no inverno e baixa no verão. As variações da comunidade fitoplanctônica e dos nutrientes parecem ter sido influenciadas principalmente pela sazonalidade. A ausência de diferenças significativas entre os tratamentos, provavelmente se devem ao pequeno número de tanques e peixes utilizados, e à hidrodinâmica dos ambientes estudados, os quais são influenciados pelos influxos dos rios à montante.Palavras-chave: fitoplâncton, estrutura da comunidade, tanques-rede, efeitos da hidrodinâmica.

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“…(Baccarin et al, 2005;Degefu et al, 2011;Santos et al, 2012), and therefore special attention should be paid to the frequency of limnological and sanitary aspects of the water. Fish farming in the reservoirs used for irrigation may benefit aquaculture systems integrated with agriculture (Behera et al, 2012), however, there is a need to apply monitoring programmes regarding not only the physico-chemical parameters, but also the analysis of cyantoxins and microbiological indicators that are rarely included in the monitoring of the fish farm water quality.…”

Section: Discussionmentioning

confidence: 99%

“…The intensive fish culture in cages can lead to the eutrophisation of water bodies and to the emergence of deleterious effects on the water quality, such as the blooms of toxic cyanobacteria that are harmful for wildlife and humans. There are several works on the effect of fish culture in cages on water quality (Ntengwe et al, 2008;Azevedo et al, 2011;Degefu et al, 2011;Schenone et al, 2011). Cage fish farming is usually performed in small water bodies such as fish ponds and reservoirs, which are often used for plant irrigation.…”

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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Influence of fish cage farming on water quality and plankton in fish ponds: A case study in the Rift Valley and North Shoa reservoirs, Ethiopia

Cited by 69 publications

References 25 publications

Supplemental effects of mixed ingredients and rice bran on the growth performance, survival and yield of Nile tilapia, Oreochromis niloticus reared in fertilized earthen ponds

Supplemental effects of mixed ingredients and rice bran on the growth performance, survival and yield of Nile tilapia, Oreochromis niloticus reared in fertilized earthen ponds

Influence of fish farming in net cages on phytoplankton structure: a case study in a subtropical Brazilian reservoir

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

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