Vital economic threat of predatory birds and parasites to cultivated fishes in Egypt

Radwan, Mahmoud

doi:10.1016/j.aquaculture.2021.737666

Cited by 10 publications

(6 citation statements)

References 53 publications

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“…Total ammonia was also found to be higher in fish farms than in lakes, which might be due to large fish stocks, fish excretion, and the breakdown of extra un-consumed diet, all of which are ammonia sources in ponds. These findings corroborate previous research (Konsowa, 2007;Radwan et al, 2021;Radwan, 2022).…”

Section: Discussion Water Quality and Fish Parasites Relationshipsupporting

confidence: 93%

“…They were not tarnished when they were photographed (Elsheikha and Elshazly, 2008;El-Shahawy et al, 2017). However, the approaches described in Yamaguti (1963), Cheng (1973), and Radwan (2022) were used to identify helminths. Cestodes, nematodes, and trematodes were relaxed in warm water for 6 h before being fixed in 5% formalin and transferred to 70% ethanol (Oros et al, 2010).…”

Section: Parasitological Assessmentsmentioning

confidence: 99%

“…This finding might be due to fish skin that may be more sensitive to infective parasite stages penetration and the detritus and benthic invertebrates consumed by this fish at different periods. Nile Tilapia is considered an intermediate host which is suitable for many parasite phases when favorable physico-chemical properties are present (El-Shahawy et al, 2017;Shehata et al, 2018;Radwan, 2022).…”

Section: Parasitological Outcomesmentioning

confidence: 99%

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Fish Parasites and Heavy Metals Relationship in Wild and Cultivated Fish as Potential Health Risk Assessment in Egypt

Radwan

Abbas

Afifi

et al. 2022

Front. Environ. Sci.

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Despite wide studies of biomonitoring aquatic environment through dynamics of host–parasite interaction, bio-indicators to track the influence and accumulation of heavy metals on fish are still few. The present study sheds light on the relation between fish parasites and heavy metals as it threatens fish’s health and, as a consequence, that of humans after fish consumption. Samples of Nile tilapia (Oreochromis niloticus) were collected in Burullus Lake, a wild fish source, and from a private fish farm in Kafr El-Sheikh Governorate, in Egypt. They were exposed to various pollutants associated with anthropogenic activities to determine the levels of accumulation of Fe, Zn, and Cu, along with the top three most toxic metals (As, Cd, and Pb) in water and fish tissues of gills, intestine, liver, and muscles in both wild and farmed O. niloticus. The results showed the order of abundance: Fe < Zn < Pb < Cu < As < Cd. In waters of both farmed and wild fish, there was a significant negative relation between parasite prevalence and heavy metals, including Zn, Pb, and As. Also, there was a significant positive relation between parasite prevalence with Cu while no significant relation was found with Fe and Cd. Heavy metal content was significantly higher (p > 0.05) in non-infected than infected farmed and wild O. niloticus. In addition, a significantly decreased concentration (p > 0.05) of essential heavy metal was recorded in wild fish compared to farmed specimens, while non-essential heavy metal was significantly higher (p > 0.05) in wild compared to farmed fish. Bioaccumulation factors (BAF) of different organs of O. niloticus were ranked in ascending order: Liver > Gills > Intestine > Muscles. In general, the risk assessment showed safe human consumption of farmed and wild fish under the reported environmental conditions in this study. Moreover, the parasite's presence can be adopted as a surrogate indicator to estimate the potential impact of heavy metal pollution and accumulation.

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Section: Discussion Water Quality and Fish Parasites Relationshipsupporting

confidence: 93%

Section: Parasitological Assessmentsmentioning

confidence: 99%

Section: Parasitological Outcomesmentioning

confidence: 99%

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Fish Parasites and Heavy Metals Relationship in Wild and Cultivated Fish as Potential Health Risk Assessment in Egypt

Radwan

Abbas

Afifi

et al. 2022

Front. Environ. Sci.

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“…The economic impact of parasites is more evident for farmers than for fishers (Lafferty et al ., 2015). Therefore, it is not surprising that most of the analyses of the costs associated with parasitic diseases focus on fish farms (Abolofia et al ., 2017; Tavares-Dias and Martins, 2017; Peterman and Posadas, 2019; Fernández Sánchez et al ., 2022; Radwan, 2022). Regardless, in both situations (i.e.…”

Section: Economic Impact Of Metazoan Parasites Of Fish From Twmentioning

confidence: 99%

Ecology and effects of metazoan parasites of fish in transitional waters

Giari

Castaldelli²,

Timi³

2022

Parasitology

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Given the abundance, heterogeneity and ubiquity of parasitic organisms, understanding how they influence biodiversity, evolution, health and ecosystem functionality is crucial, especially currently when anthropogenic pressures are altering host–parasite balances. This review describes the features, roles and impacts of metazoan parasites of fish occurring in transitional waters (TW). These aquatic ecosystems are highly productive and widespread around the globe and represent most favourable theatres for parasitism given the availability of hosts (invertebrates, fishes and birds) and an increased probability of parasite transmission, especially of those having complex life cycles. Fascinating examples of how parasitism can influence different hierarchical levels of biological systems, from host individuals and populations to entire aquatic communities, through effects on food webs come from this kind of ecosystem. Edible fish of commercial value found in TW can harbour some parasite species, significantly reducing host health, marketability and food safety, with possible economic and public health consequences. Many TW are historically exploited by humans as sources of relevant ecosystem services, including fisheries and aquaculture, and they are highly vulnerable ecosystems. Alteration of TW can be revealed through the study of parasite communities, contributing, as bioindicators, for assessing environmental changes, health and restoration. Fish parasites can provide much information about TW, but this potential appears to be not fully exploited. More studies are necessary to quantify the ecological, economic and medical impacts fish parasites can have on these important ecosystems.

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“…Otieno (2019) estimated that farmers may lose ∼15% of their production of inland freshwater aquaculture finfish to piscivorous birds each season in the western Kenya region alone. In many parts of the world, additional potential impacts include fish die-offs as a result of disease transmission and parasitic infestation mediated by some piscivorous bird species (Walakira et al, 2014;Radwan, 2021). In developing countries, small-scale fish farmers' capacity to find solutions aimed at minimizing these losses are often undermined by challenges in accessing credit facilities to mobilize the requisite financial and infrastructural investments, and these are usually superimposed on the farmers' inherently low levels of operational scale (Quagrainie et al, 2010).…”

Section: Introductionmentioning

confidence: 99%

Effectiveness of physical barriers and enhanced fertilization in controlling predation on tilapia and catfish aquaculture systems by four piscivorous water bird families

Otieno¹,

Shidavi²

2022

Front. Sustain. Food Syst.

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Waterbirds cause substantial fish-stock losses in open aquaculture systems, particularly in developing countries where fish-ponds are smaller and predator control methods largely manual or under-resourced. This study: (1) used three fish-pond treatment meassures to assess their efficiencies in deterring predation pressure by four piscivorous waterbird families in small tilapia and catfish farms in western Kenya; and (2) distinguished bird group(s) most effectively deterred by these measures. The treatment measures were: coarse-grid wire mesh barriers; finer-grid wire barriers; and enhanced pond fertilization. Twelve fish-ponds were randomly sampled to assess birds' pond-neigborhood assemblages and their predation deterrence responses to pond treatment effects. Bird species richness was not affected by pond cover status, enhanced pond fertilization or type of pond cover barrier. However, pond-cover status, singularly and interactively with enhanced fertilization, reduced bird encounter rates while cover barrier type did not. Conversely, cover status, cover barrier type and fertilization each separately but not interactively contributed to improved deterrence to bird predation rates overall. However, while predation by families of larger birds was effectively reduced by enhancing pond fertilization or cover barriers, predation by families of smaller birds was prevented only by fine-grid chicken-mesh barriers. These results demonstrate that using enhanced fertilization and physical barriers can significantly contribute to reduction in predation pressure on open-culture pond-fish by most piscivorous birds, but may not always be effective if used separately. Effectiveness of combination of measures chosen will depend on types of target bird species and their feeding habits. The results constitute additional knowledge on field techniques useful in diversifying solution options for minimizing impacts of vertebrate predation on pond-fish stocks toward promoting sustainable aquaculture production and improving rural human nutrition.

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Vital economic threat of predatory birds and parasites to cultivated fishes in Egypt

Cited by 10 publications

References 53 publications

Fish Parasites and Heavy Metals Relationship in Wild and Cultivated Fish as Potential Health Risk Assessment in Egypt

Fish Parasites and Heavy Metals Relationship in Wild and Cultivated Fish as Potential Health Risk Assessment in Egypt

Ecology and effects of metazoan parasites of fish in transitional waters

Effectiveness of physical barriers and enhanced fertilization in controlling predation on tilapia and catfish aquaculture systems by four piscivorous water bird families

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