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Résumé Afin d'évaluer l'impact potentiel de la vidange, les flux de nutriments et de matières sont quantifiés lors du remplissage et de la vidange d'un étang construit en dérivation, à l'aval d'une chaîne d'étangs. La cinétique de vidange a été établie à l'aide d'un modèle numérique de terrain restituant la surface topographique de l'étang. Les mat...
Citations
... Water discharged from ponds contains considerable amounts of nutrients (Schwartz and Boyd, 1994;Cao et al., 2007) and the resuspension of the pond bottom due to fish movement, fishing activities and drag of the discharging water increases the concentrations of suspended solids in the effluents (Schwartz and Boyd 1994;Szab o 1994;Lin et al., 2001;Banas et al., 2008). In previous studies, the mean concentration of TSS in pond effluents during drainage ranged from 84 mg/l (Hargreaves et al., 2005a) to 4308 mg/l (Vallod and Sarrazin 2010), with peak concentrations of more than 40,000 mg/l (Hargreaves et al., 2005a). The impact remains highly pond-specific, depending on the management practice employed (Frimpong et al., 2004). ...
... Although the TSS loading rates could not be estimated for the whole drainage process for all operations, they covered the most adverse steps of the procedure: Several authors suggest that the highest TSS concentration in surface drains is reached in the final step, when 20e40% of the suspended material is discharged with only 2e5% of the water (e.g. Banas et al., 2002;Vallod and Sarrazin 2010). These results therefore represent minimum loading rates and likely underestimate the effect of the drainage operations. ...
... Banas et al. (2008) measured mean values around 60 mg/l for the draw down step and 1150 mg/l for the final fishing step during drainage of extensive carp ponds between 2 and 620 ha, with maximum values exceeding 4000 mg/l. Another study on carp pond drainage in France reported mean TSS concentrations between 30 and 4300 mg/l during the drainage of a 24 ha pond (Vallod and Sarrazin 2010). The comparable effect of reported TSS values and the present pond drainage operations, despite their much smaller size, show that the activities during the fish harvest rather than the pond size seem to be the main cause of high TSS concentrations in the effluents. ...
Extensive fish production in earthen ponds is a common aquaculture practice, which requires draining of the ponds for fish harvesting. Despite their value for biodiversity and water retention, the impact of fish ponds on the receiving streams as regards fine sediment and nutrient pollution remains controversial. This holds particularly true for streams with endangered freshwater pearl mussels, requiring a highly permeable stream bed with low fine sediment content for successful juvenile development. This study quantified the amount of fine sediment, suspended solids and nutrients delivered to pearl mussel streams in relation to the pond characteristics, distance to the receiving stream and applications of measures to prevent the input of fines. Comparing fine sediment deposition above and downstream of the pond inlets after 21 pond drainage operations, as well as continuous measurements of the turbidity for 12 operations revealed varying effects of pond fishing on the receiving streams. Average fine sediment deposition was increased by nearly 6-fold compared to upstream and maximum turbidity values for single drainage operations exceeded 460 NTU. Draining between 1% and 92% of the water volume of individual ponds resulted in additional loading of 0.07 - 4.6 t suspended particles. Physical mitigation structures that prevent mobilized material from reaching the receiving stream significantly reduced the fine sediment input and deposition rates. Harvesting methods that do not require complete drainage of the pond reduced the turbidity by ten-fold. Without mitigation measures, the impact of pond drainage operations on the fine sediment deposition was comparable to high discharge events. No significant increase in nutrient concentration was observed during most drainage operations. These results reveal remarkable effects of pond drainage on the aquatic environment, as well as the possibility to minimize such impacts as switching to harvest methods that do not require complete pond drainage and installation of sedimentation structures.
... Fish species introduced every spring in the fishponds in both study areas are similar and are mainly dominated by common carp (Cyprinus carpio), followed by white fish, tench (Tinca tinca), and some piscivorous species such as pike (Esox lucius), pikeperch (Sander lucioperca) or perch (Perca fluviatilis) (Vallod and Sarrazin 2010;Wezel et al. 2013b). In total, 83 ponds were sampled in the Dombes area between 2007 and 2009, and 35 ponds in the Forez area between 2011 and 2014. ...
Fishponds are often enriched with nutrients in order to increase phytoplankton and zooplankton populations to support fish production. This eutrophication often leads to a global decrease of biodiversity. This biodiversity shift may be identified by a tipping point, the value of an environmental parameter above which a significant change of species richness and abundance occurs. A total of 110 eutrophic to highly eutrophic fishponds were studied in two areas in France to investigate parameters governing dragonfly species richness and species abundance by determining tipping points. Parameters investigated were chlorophyll a (CHL), water transparency, total N (TN), total P (TP), aquatic plant richness and coverage, adult dragonfly richness and abundance, and fish harvest. A high species richness of dragonflies was found in fishponds, with a total of 34 species, including six species of conservation concern. Dragonfly richness and abundance was shown to be negatively influenced by higher degrees of eutrophication. A high diversity of dragonflies occurred in the fishponds with CHL concentrations below 127 µg/l, water transparency above 67 cm, TN concentrations below 2.30 mg/l, and a fish harvest smaller than 253 kg/ha. A minimum of 5% of aquatic plant cover and the presence of a minimum 9 aquatic plant species seem to promote the richness and abundance of dragonflies. According to tipping points, 19 dragonfly species could be determined as indicator species for water quality in fishponds.
... One of the most important characteristics that distinguish man-made reservoirs-fishponds from the natural ones-shallow lakes, is a periodical harvesting of fish stock. This action is followed by more or less serious emissions of resuspended sediments which are rich in various elements, predominantly in phosphorus (Butz 1988;Banas et al. 2002;Vallod and Sarrazin 2010). Both phases of the fishpond harvesting, (1) the fishpond draining (water draw down), i.e. process of gradual fishpond emptying when usually no emissions of sediment are visually observed, and (2) fish stock harvesting, i.e. process of fish catching using nets when fish and fishermen act intensively in shallow muddy water and large amount of suspended solids leave the pond, proved to be the important periods concerning mass balance of nutrients. ...
Abstract Fishponds exhibit high natural retention potential for phosphorus, which enters
the ponds from non-point, diffuse and point sources, as well as from aquaculture management.
Results of phosphorus mass balance monitoring of nine large fishponds
(60–449 ha) over 2010–2014 revealed total phosphorus retention ranging between -66 %
(sink) and ?52 % (release) of the P loads from inflows, i.e. specific P retention varied
between -7.83 g m-2 (sink) and 1.00 g m-2 (release) of surface area, per one fish production
cycle. Retention of P was eliminated by application of fertilizers (with simultaneous
fish feed application) during fish production process and/or by massive P release
from fishpond sediments after previous heavy loads. P retention could be increased by
preference of surface water outflow instead of bottom discharge and/or also by minimizing
of emissions of suspended sediment particles during a fish harvesting. The real role of
fishponds in transport processes of P throughout a watershed could be eruditely assessed
only by following newly proposed method called ‘‘new approach’’ when P input (via
inflows) and P output (via outflows) are compared with natural fishpond ability to retain P,
which is determined by a simple model proposed by Hejzlar et al. (2006). For evaluation of
effect of actual fishery management, the ‘‘culture-balance’’ method is suitable too. If the P
inputs (stocked fish, fertilizing, feeding) and outputs (harvested fish) derived from fishery
practice were in balance, the P retention did not decline. However, in condition of
inputs[outputs, the P retention appreciably ceased or was totally eliminated. It was
concluded that fishponds could serve as an important sink of P transported throughout a
watershed even under semi-intensive fish (common carp) production condition.
Keywords Eutrophication � Fish � Fishery management � Phosphorus retention � Pond �
Water quality
... Pour les étangs situés en tête de bassin versant, les eaux de ruissellement représentent Les étangs en amont des chaines sont alimentés principalement par quatre cours d'eau (Degorce, 1995). Ceux situés plus en aval sont alimentés par l'eau de ruissellement des bassins versants ou par la vidange des étangs en amont (Vallod et Sarrazin, 2010). La vidange des étangs lors des pêches est effectuée par un exutoire appelée la bonde et est organisée d'aval en amont des bassins versants pour empêcher le débordement de certains étangs situés plus bas dans le bassin versant (Degorce, 1995). ...
... Les étangs de la plaine du Forez ne subissent normalement pas une phase d'assec cyclique (Degorce, 1995;Vallod et Sarrazin, 2010;Wezel et al., 2013a). Des assecs peuvent toutefois être occasionnellement pratiqués après de nombreuses années en eau. ...
... The age of fish ponds in our study averaged 3 years since the last one-year dry period in the Dombes area. In the Forez area, this management practice has not been applied since 10 or 20 years for most of the ponds (Vallod and Sarrazin, 2010). In this region, the age of fish ponds averaged 10 years since the last dry period. ...
Les étangs piscicoles sont des milieux souvent enrichis en nutriments dans le but d’accroître la productivité global du système afin d’augmenter la biomasse de poisson. De fortes concentrations en nutriments peuvent entraîner une eutrophisation de l’étang conduisant à une perte de la biodiversité de l’étang et à une dominance du phytoplancton. Ce changement peut être caractérisé par un seuil critique, appelé point de basculement, où un changement significatif de la richesse en espèces et/ou de l’abondance survient dans plusieurs groupes taxonomiques. Les points de basculement ont été déterminés dans les étangs de la Dombes et du Forez. (1) Dans un premier temps, les points de basculement ont été déterminés dans différent groupes taxonomiques grâce à trois méthodes statistiques différentes en utilisant cinq indices de diversité, ceci afin d’évaluer les meilleures méthodes d’analyses. (2) Dans un deuxième temps, les changements pluriannuels des points de basculement ont été évalués en relation avec les concentrations en nutriments, les plantes aquatiques et les conditions météorologiques. (3). Par la suite, les points de basculements chez les Odonates ont été déterminés en relation avec des gradients d’eutrophisation du système, la richesse des plantes aquatiques et le recouvrement végétal, et la production piscicole. (4) Pour finir, le rôle des différentes pratiques piscicoles dans les étangs comme la fertilisation, l’addition de nourriture artificielle, le chaulage, et la mise en assec des étangs, a été étudié en relation avec la production piscicole, la diversité en espèces des plantes aquatiques, et l’eutrophisation du système. Nos résultats ont montré une importante variation des points de basculement suivant les différentes méthodes statistiques et les indices de diversité utilisés. Pour tous les groupes taxonomiques, les plantes aquatiques se sont révélées être les plus influencées par l’eutrophisation dans les étangs piscicoles. Les points de basculement ont montré une importante diminution de la diversité en espèces des plantes aquatiques et du recouvrement végétal, liés aux concentrations en nutriments qui dirige la compétition entre les producteurs primaires, à savoir le phytoplancton et les plantes aquatiques. Les points de basculement sont donc liés directement aux deux équilibres stables de dominance des plantes aquatiques ou du phytoplancton. Toutefois, les points de basculements peuvent varier significativement suivant les années, principalement due aux conditions météorologiques qui surviennent au printemps. De plus, la diversité en espèces et l’abondance des Odonates ont montré être négativement influencés par une trop forte eutrophisation du système. Les points de basculement sont très importants pour les gestionnaires des étangs qui pourront ainsi gérer leurs étangs de manière à garder un milieu équilibré et ainsi apporter le moins d’intrants possibles. Nos résultats ont ainsi montré qu’une mise en assec est la pratique permettant d’optimiser au mieux le système : productivité piscicole élevée, richesse des plantes aquatiques élevée et faible concentration de chlorophylle α. Ainsi, pour atteindre un bon état écologique de l’étang, une mise en assec des étangs doit s’effectuer toutes les quatre à cinq ans. Par conséquent, il est ainsi possible de prédire grâce aux points de basculement, le moment où l’état d’équilibre de l’étang va basculer vers une dominance phytoplanctonique. Des points de basculement ont ainsi été déterminés dans le but de maintenir une forte diversité de plantes aquatiques et un fort recouvrement végétal, pour préserver une forte biodiversité des étangs et une bonne productivité piscicole.
... Research carried out in Austria by Kainz (1985), for example, found no negative impact on receiving water quality from traditionally managed carp pond facility. As indicated by Butz (1988), Banas et al. (2002Banas et al. ( , 2008 and Vallod and Sarrazin (2010), however, nutrient outflow may not pose problems during the growing season, but pond draining preceding the annual harvest and during harvesting operations can significantly increase loading in receiving waters due to mobilisation of sediments. ...
... During the growing season, the physicochemical and biological parameters of inlet water have been changed by the time it is discharged due to a number of factors, including stocking density, species composition, management methods, climatic conditions, Table 1 Negative impacts of pond aquaculture on the environment Physicochemical and biological issues References 1. Modification of water temperature and flow rate profiles Billard and Perchec (1993), Beveridge (1984), Všetičková et al. (2012) 2. Increased concentration of suspended solids, BOD, COD, forms of N (including ammonia), phosphorus Warrer-Hansen (1982), Muir (1982), Boyd and Tucker (1998) Všetičková et al. (2012) 3. Reduced concentration of dissolved oxygen Bergheim and Silvertsen (1981), Boyd and Tucker (1998), Všetičková et al. (2012) 4. Alteration of water quality due to the use of chemicals and antibiotics Buchanan (1990). Boyd and Massaut (1999) 5. Generation of organic-rich sediments Holmer (1992), Lin et al. (1998), Lin et al. (1999), Lin and Yi (2003), Vallod and Sarrazin (2010) 6. Occurrence of algal blooms in eutrophic waters Gowen et al. (1990) elevation, original quality and quantity of inflow water, hydraulic retention time, pond volume, morphology and area, outlet location (surface, bottom) and many others . In general, water discharged from ponds supplied with good-quality water has a higher temperature, and increased nutrient loading (mainly in the form of ammonia and phosphates), dissolved substances and suspended solids content (Kanclerz 2005;Kopp et al. 2012;Všetičková et al. 2012). ...
... Excess P in fish diet results in higher levels of excreted P, and this is one of the main causes of eutrophication in ponds (Kim et al. 1998;Jahan et al. 2003), often also resulting in impaired water quality downstream. Sediment-bound P is a major problem in carp ponds, and about half the P in a pond can be controlled by monitoring the output of solids (Pursiainen 1988;Vallod and Sarrazin 2010). ...
Discharge of aquacultural wastewater can lead to eutrophication and disruption of natural ecosystems in receiving water bodies. A controlled waste production strategy is necessary, therefore, in order to maintain sustainable aquacultural growth. Along with fertilisation, supplementary feeding is the major source of allochthonous matter in aquaculture and management of aquacultural waste, therefore, should be approached through diet formulation and/or feeding strategy. The introduction of highly digestible feed has reduced solid waste excretion, and further reductions can be achieved through careful selection of ingredients and processing to improve nutrient availability. Dissolved nitrogen waste can be reduced by ensuring a balance between protein and energy, such that fish use non-protein sources as energy, while phosphorous waste can be reduced through careful ingredient selection and processing to improve digestibility. Thermal and mechanical treatment of feed cereals prior to application can also help decrease the amount of poorly or undigested feed. Finally, feeding practices that minimise wastage should also be explored as they have a significant impact, not only on waste output but also on the overall economy of carp pond farming.
... First, most of the ponds are almost completely emptied for a few days every year for the fish harvest. During the emptying of the ponds, a certain amount of sediment is mobilized, in particular at the end of the emptying phase (the last two to three days and particularly during fish harvesting in the last few hours; Banas 2001, Vallod andSarrazin 2010). ...
Agricultural land use in the area of water bodies is generally considered to increase the nutrient status of the water body water and sediments, but is this also the case for already nutrient-rich fish ponds? We studied 83 fish ponds in the Dombes region, France, where 1100 ponds are located in a heterogeneous agricultural landscape. Different water and sediment parameters were analysed for ponds and in ditches after rainfall events. Land use was studied in the primary catchment of ponds and in a 100-m zone around ponds. Soil parameters of different land-use types were analysed and farmers interviewed about agricultural practices. Increasing cropping area in the catchment of the ponds is significantly correlated to higher PO43- concentration of pond water and to a lower degree, also to NO3−, but only in certain years with higher rainfall and with a more uneven distribution in spring. Sediment parameters were not significantly influenced. High NO3- concentration in the water of a ditch during significant rainfall events was found for a cropland dominated catchment.Citation Wezel, A., Arthaud, F., Dufloux, C., Renoud, F., Vallod, D., Robin, J., and Sarrazin, B., 2013. Varied impact of land use on water and sediment parameters in fish ponds of the Dombes agro-ecosystem, France. Hydrological Sciences Journal, 58 (4), 854–871.
... Normally these shallow ponds are emptied every year for fish harvest and then refilled. In France for example, different regions with a high density of fish ponds can be found: the Dombes (1100 ponds, 11,500 ha) (Bernard and Lebreton, 2007), the Lorraine (about 7000 ha of ponds) (Le Bihan and Font, 2008), the Brenne (1300 ponds, 8500 ha) (PNR de la , the Forez (300 ponds, 1500 ha) (Ministère de l'Ecologie et du Développement Durable, 2007;Vallod and Sarrazin, 2010), the Bresse-Jura (600 ponds, 2000 ha) (Ministère de l'Ecologie et du Développement Durable, 2005), as well as the Franche-Comte region with a lower number of fish ponds (Schäffer-Guignier, 1994). In Poland, the greatest agglomerations of fish ponds are found in the south-west (Bukacińska et al., 1995). ...
... First, most of the ponds are almost completely emptied every year for a few weeks for fish harvest. During the emptying period, which lasts a few days, part of the sediment is mobilised and leaves the pond with the water discharge (Vallod and Sarrazin, 2010). Secondly, in average after every third year, the ponds are emptied completely in winter and leaving them without water during the following year. ...
In aquaculture, management practices such as supplementary feeding or fertilisation of water are generally considered to improve fish yield in ponds or shallow lakes. Nevertheless, in semi-natural systems where many ponds or lakes are situated in a cultural landscape, this is much less evident for certain fish farmers because fish production systems are often quite extensive, and fish production is only one economic activity among others for these fish farmers. In this paper we analyse the influence of different management practices on fish yield and nutrient status of fish ponds’ water and sediments, and we have an additional regard on potential implications of this in the perspective of the European Water Framework Directive. This directive demands that artificial water bodies such as fish ponds have to attain a good ecological potential in 2015, and thus to adapt water body management to achieve this.
Agroecology largely focusses on terrestrial agroecosystems, but it can also be applied to fish farming. Indeed, ponds are typically used for fish production in Europe, but are also important reservoirs of biodiversity. Numerous studies demonstrate that both fish production and biodiversity are strongly determined by human management. One key practice in extensive fish farming, although more rare in Europe, is to dry out ponds. They are left dry for a complete year after several years of fish production. However, the extent to which this practice affects the functioning of the ecosystem, its biodiversity and fish production remain unclear.
We investigated data from 85 fish ponds in the Dombes region, France, sampled between 2007 and 2014. We related variation in key abiotic characteristics to the time since last dry out. The dataset included organic matter content in pond sediments and concentrations of inorganic nitrogen and phosphorus in the water column, and biotic components such as macrophytes cover and richness, phytoplankton concentration and richness, macroinvertebrates density, and fish yield.
Our results show that drying out facilitates the mineralization of organic matter in sediments and results in higher concentrations of inorganic nitrogen in the water column. Macrophytes cover is highest during the first year after drying out, and gradually declines after at the expense of increasing phytoplankton concentration. The diversity of both is highest in the first year after drying out and declines rapidly, especially for macrophytes. Fish yield is at its maximum in the second year.
Drying out fish ponds appears to be an important agroecological practice in extensive fish farming with an application every three to four years. By nutrient recycling, this practice has a positive impact on the balance between primary producers and indirectly on the whole food web during two years. It optimizes fish production and allows biodiversity conservation.
This chapter presents the investigation of the accumulation of heavy metals in six fish species obtained in four provinces around Tonle Sap Lake. They are the species commonly caught by fishermen in the lake. The results showed that the mean concentration levels of zinc, lead, chromium, copper, cadmium, and arsenic in the fish samples were below the maximum permissible limits (MPLs) set by the FAO/WHO. By contrast, the mean concentrations of manganese (Mn) and nickel (Ni) exceeded the MPL in all species, raising concerns about possible health problems caused by these metals. The highest concentration of Mn was found in Anabas testudineus (10.1 mg/kg-wet) followed by Boesemania microlepis (4.07 mg/kg), whereas the highest concentration of Ni was found in A. testudineus (0.79 mg/kg) followed by Channa micropeltes (0.41 mg/kg) and Boesemania microlepis (0.36 mg/kg). The predatory (carnivorous) fish A. testudineus also showed effective bioaccumulation of the other heavy metals, which is consistent with the findings of other studies. The presented results are valuable in the assessment of the safety of these fishes as important sources of protein for the villagers and other consumers.
