Water Quality of Borehole and Shallow Wells Feeding Artificial Fish Ponds in Bechar Province, Southwestern Algeria: Bacteriological and Physicochemical Aspects

Aquaculture represents a true tool for economic diversification, serving as a source of employment, income and livelihoods for countries. It is not limited to coastal areas but also extends to inland communities, where fish farming ensures a vital food supply (ILO, 2021). According to the International labour organization (ILO), China alone accounts for 57.76% of global production. Following China are Indonesia, India, Vietnam and Bangladesh, which contribute 12.9%, 6.18%, 3.63% and 2.1%, respectively.
       
Egypt (1.36%) is the only African country among the top 15 producers, ranking 8th globally. This success has encouraged Algerian authorities to initiate partnership agreements with Egypt, aiming to develop Saharan aquaculture in Algeria’s southern regions. The goal is to enhance food security in response to rapid population growth, meet local dietary preferences and create sustainable employment opportunities. According to the FAO (Horizons Magazine, 2024), Algeria’s annual aquaculture production ranges between 6,000 and 7,000 tons per year. With 200 registered aquaculture projects, the country aims to achieve 100,000 tons by 2030. This economic activity contributes to food security, food safety and, from a nutritional perspective, fish provide a balanced diet rich in proteins, vitamins and fats for consumers (Adebami et al., 2020; Abbani et al., 2022).
       
Given the limited water resources in Algeria’s arid and semi-arid regions, integrated aquaculture systems are increasingly being adopted for sustainable water use (Abbani et al., 2022; Mramba and Kahindi, 2023; Mondal et al., 2025). However, the physicochemical and bacteriological properties of the water used in aquaculture operations, particularly in non-coastal regions, play a crucial role in the success of this activity (Eghomwanre et al., 2019; Nair and Nayak, 2023).
       
Bacterial indicators such as coliforms and fecal streptococci are essential to assess microbiological contamination, as they signal the potential presence of pathogens capable of causing diseases in fish and humans (Tyagi et al., 2006: Korajkic et al., 2018; Leight et al., 2018).
       
Indeed, water that does not meet sanitary standards can affect the performance and health of fish and consequently, the health of consumers (Ntengwe and Edema, 2008; Sule et al., 2016; Olukunle and Oyewumi, 2017). Recent studies, such as those by Ajayi and Okoh (2014) and Mramba and Kahindi (2023), have highlighted the importance of stringent water quality management to limit the spread of contaminants and bacterial pathogens in aquaculture systems.
       
This study aims to analyze the bacteriological and physicochemical quality of water used in fish farming across three regions of Bechar (Southwestern Algeria): the Boukais fish farming station (CNRDPA), the Taghit fish farm and the Nif Rhaa fish farm in Ouakda, in relation to sanitary standards and to assess potential risks to public health.

Experimental period
 
All experiments were conducted over a period of eight months, from January to August 2024, at MTU-Bechar and the CNRDPA-Boukais research center in Bechar, Algeria.
 
Study area
 
Three fish farms were studied, located in Boukais, Taghit and Nif Rhaa-Ouakda, situated approximately 50 km, 90 km and 15 km, respectively, from the center of Bechar (Fig 1). These farms are located in arid Saharan environments and are specialized in tilapia farming, particularly Red Tilapia and Nile Tilapia (Fig 2). In Taghit and Nif Rhaa-Ouakda, an integrated aquaculture-agriculture system is practiced, with fish raised in both concrete irrigation water storage ponds and earthen ponds.



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Water sampling and analysis
 
Sampling conditions
 
The sources of water used in the aquaculture activities are boreholes and shallow wells. Water samples were collected in sterile glass flasks, following the guidelines of ISO 5667-1 (2023) (Fig 3).

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All sampling was conducted in the early morning to reduce the influence of temperature fluctuations on water parameters. Samples were then transported in cool boxes and stored at 4^oC to preserve their integrity before analysis. The frequency and specific dates of water sampling are provided in Table 1.



Physicochemical parameters
 
The physicochemical parameters-pH, temperature, electrical conductivity and total hardness-were analyzed using the standard procedures provided by the APHA and WEF (Lipps et al., 2022).
 
Bacteriological parameters
 
Bacteriological analysis was conducted using international standard procedures, as outlined in Table 2.


 
Interpretation of bacteriological and physicochemical analyses results
 
The quality of water samples is evaluated by comparing the bacteriological and physicochemical parameters to the established thresholds limits for groundwater and drinking water, as outlined in national regulations (JORA n.18, 2011; JORA n.34, 2011; JORA n.13, 2014) and by the World Health Organization (WHO, 2017).

Physicochemical analysis
 
The results of the physicochemical analysis of the water supplying the fish ponds are shown in Table 3.


       
Limited water availability is one of the major challenges to aquaculture development in southern Algeria, a region marked by low rainfall, scarce freshwater resources and heightened susceptibility to climate change (Mramba and Kahindi, 2023). Consequently, experts are focusing on sustainable aquaculture practices in these areas, with an emphasis on water resource planning and management. One approach being explored is the integration of aquaculture with agricultural activities to benefit both sectors (Abbani et al., 2022).
       
For physicochemical parameters, temperature plays a vital role in aquatic ecosystems, affecting the chemical and physicochemical properties of the water, as well as the organisms inhabiting the pond (Eghomwanre et al., 2019). The recorded average temperatures ranged from 18^oC to 21^oC, with a minimum of 13^oC and a maximum of 29.5°C, variations that are primarily by the season. However, these values meet the requirements of national regulations.
       
pH is an essential environmental factor that influences the survival, physiology, metabolism and chemical processes of aquatic organisms. It plays a key role in regulating their life cycles and affects the solubility and availability of nutrients. Moreover, pH helps maintain the carbonate and bicarbonate buffering systems, which are vital for the growth and survival of aquatic plants (Eghomwanre et al., 2019; Nair and Nayak, 2023).
       
The pH results of this study fall within the national regulatory range of 6.0 to 9.0, which is considered optimal for fish production. These findings are consistent with the study by Eghomwanre et al., (2019), where 6 out of 10 samples analyzed had pH values ranging from 6.09 to 6.95. Similar results were reported by Ajayi and Okoh (2014), with pH values between 7.82 and 8.15, by Olukunle and Oyewumi (2017), with values ranging from 7.1 to 8.39 and by Mramba and Kahindi (2023), with values ranging from 6.5 to 7.3. It is also consistent with our previous study (Benyagoub, 2023a, Benyagoub, 2024) on the Ouakda groundwater, which is part of the Turonian and Quaternary aquifers (Kabour et al., 2010; Seddiki and Cherif, 2021) with a pH ranging from 7.33 to 8.17, as well as the results of Rezzoug et al., (2017), who reported pH values of 7.48 and 7.68. According to Mramba and Kahindi (2023), the pH of pond water should ideally be between 6.5 and 9.5 for effective fish farming. However, certain species may thrive in pH levels between 7.5 and 9, particularly in warmer temperatures (16-27^oC), which have been found to be conducive to tilapia productivity in small ponds (Ntengwe and Edema, 2008).
       
The electrical conductivity (EC) results for the Taghit and Nif Rhaa-Ouakda samples fall within the national regulatory limits and are consistent with the findings of our previous study (Benyagoub, 2023a), with EC values ranging from 973 to 1130 mS/cm. However, the Boukais samples exhibit higher EC due to increased total hardness (TH) values, which are also related to the pH of the medium. The TH and EC results are higher than those reported by Ajayi and Okoh (2014), Olukunle and Oyewumi (2017) and Eghomwanre et al., (2019). This may be due to the lithological characteristics of Quaternary limestone, where the calcium and magnesium ions contributing to hardness are released through the hydrolysis of silicate minerals found in the soil (Nabbou et al., 2020; Benyagoub, 2023a). Rezzoug et al., (2017) highlight that the soils and groundwater in the studied areas are at risk of salinization, primarily due to the high salinity of irrigation water, a consequence of the declining water table. This salt buildup worsens during the hot summer months.
       
Despite the EC, TH and pH values observed in this study, Oreochromis niloticus can thrive in waters with a salinity close to 11.5g/L and a pH range of 8 to 11. It can reproduce continuously every 15 days at temperatures above 23^oC (Amoussou et al., 2016), from March to September in the studied areas known for their hot climate. However, salinity levels exceeding 16 ppt can reduce food intake and feed conversion efficiency, redirecting more energy toward maintaining homeostasis rather than supporting growth (Mramba and Kahindi, 2023). Although the current study did not conduct a heavy metals assessment due to the lack of analytical tools, a study by Barszcz et al., (2024) shows that recirculating aquaculture systems contribute to higher levels of heavy metal bioaccumulation in fish meat compared to flow-through systems. It is important to note that, according to Barszcz et al., (2024), the levels detected in the tested trout muscle samples were low and did not exceed the maximum permissible limits defined by the EU and these results were not derived from the present study.
       
This highlights the importance of water management technologies in aquaculture and their impact on food safety related to fish meat consumption.
 
Bacteriological analysis
 
The results of the bacteriological analysis of the water supplying the fish ponds are shown in Table 4 and Fig 4.




       
Given the importance of physicochemical parameters such as temperature, pH, dissolved oxygen (DO), ammonia and water clarity, the bacteriological quality of water is also a critical parameter in the aquaculture ecosystem, making it more vulnerable to disease (Mramba and Kahindi, 2023).
       
The borehole water used for tilapia farming in Nif Rhaa and Boukais demonstrated good microbiological quality. In contrast, the shallow well water from Taghit (3 out of 7 samples) and the reservoir water at the Boukais aquaculture station exhibited poor quality, with contamination by coliforms, Salmonella spp. and Pseudomonas spp., varying from one sample to another. In the Boukais reservoirs (Sb6 to Sb10), this contamination is probably attributed to the integration of recycled water-treated by sedimentation and filtration-into an elevated storage tank at a 30:70 ratio with fresh water.
       
The results of the TAMF load, coliforms and fecal streptococci from the eight contaminated samples (Sb6, Sb7, Sb8, Sb9, Sb10, St15, St16 and St17) were found to be lower than the bacterial loads reported by Ajayi and Okoh (2014), Sule et al., (2016), Eghomwanre et al., (2019) and Adebami et al., (2020).
       
Contamination by coliforms and streptococci in water samples could result from increased microbial infiltration, possibly due to fecal contamination of either animal or human origin, improper placement of the storage reservoir, insufficient treatment of the feed water storage reservoir to eliminate microorganisms, or inadequate cleaning frequency of the reservoir (Ajayi and Okoh, 2014; Benyagoub, 2023a).
       
The microbial load already present in contaminated water may be further increased by the use of animal manure, a practice sometimes used to enhance fish growth. This organic input not only enriches the pond environment with nutrients but also increases concentrations of ammonia and organic nitrogen, creating favorable conditions for the proliferation of various microorganisms (Njoku et al., 2015; Sule et al., 2016; Rathod et al., 2023). However, neglecting proper fishpond management practices (Ajayi and Okoh, 2014; Opiyo et al., 2018) could pose a health risk to the fish by facilitating the transmission of potential pathogens, which could subsequently affect human health (Sule et al., 2016). Aquaculture’s success is closely tied to a healthy aquatic environment (Cretu et al., 2016). Several studies have shown that poor water quality poses a significant threat to both fisheries and fish population restoration by inducing stress in fish and increasing their susceptibility to opportunistic pathogens (Nair and Nayak, 2023; Mramba and Kahindi, 2023; Guetarni and Labdi, 2023). Sule et al., (2016) recommend monitoring the frequency of water changes, especially in concrete ponds, as this can significantly influence the microbial load.
       
To mitigate these risks, several methods-including well construction and rehabilitation, the use of filters such as zeolite/bentonite-based ceramic filter membranes, storage tank cleaning, chlorine disinfection and proper drinking water handling practices-can improve water quality and reduce waterborne diseases that may affect fish and, consequently, consumer health (Benyagoub, 2023a; Djana et al., 2024).

Identification of potential pathogenic bacteria
 
The results of the identification of potential pathogenic bacteria in the water that supplies the fish ponds are presented in Table 5.


       
The identification of pathogenic species revealed the presence of Salmonella choleraesuis ssp. arizonae in sample Sb8 and Pseudomonas aeruginosa as an opportunistic pathogen in five samples (Sb7, Sb8, St15, St16, St17).
       
These findings support the research conducted by Ntengwe and Edema (2008), Ajayi and Okoh (2014), Njoku et al., (2015), Eghomwanre et al., (2019) and Adebami et al., (2020), who examined fish pond waters in Zambia, Ondo State, the Niger Delta, Edo State and Lagos (Nigeria), respectively. Their investigations revealed a wide variety of bacterial species present in the pond waters, including, but not limited to, Staphylococcus spp., Streptococcus spp., Micrococcus spp., Bacillus spp., Aeromonas spp., Pseudomonas spp., E. coli, Enterobacter spp., Proteus spp., Salmonella spp., Citrobacter spp. and Serratia spp. As noted by Sule et al., (2016), several bacterial infections, particularly those caused by Aeromonas spp. and Pseudomonas spp., are common in fish ponds. The findings of this study are also supported by our previous research on water stored in concrete reservoirs in Nif Rhaa-Ouakda, from which the following bacterial species were isolated: Escherichia coli, Aeromonas hydrophila, Chromobacterium violaceum, Escherichia vulneris, Enterobacter cloacae and Enterobacter amnigenus (Benyagoub, 2023a; Benyagoub, 2023b; Benyagoub, 2024).
       
The presence of bacterial species such as Pseudomonas, Streptococcus and other pathogens, including fungal and parasitic species, in the water indicates contamination. This contamination contributes to the transmission of infections and can negatively affect the growth and survival of fish in pond ecosystems (Ajayi and Okoh, 2014; Opiyo et al., 2018; Adebami et al., 2020; Mramba and Kahindi, 2023).
       
The studies by Njoku et al., (2015) and Mramba and Kahindi (2023) explored the relationship between pond water parameters, fish yield and the potential for disease outbreaks. They found that microbial contamination could reduce fish yield, contribute to disease outbreaks and result in economic losses. Additionally, it poses a risk to consumers, especially if the harvested fish are not properly processed.

The analyzed samples exhibited significant salinity, as evidenced by high hardness and electrical conductivity, particularly in the Boukais samples. These properties are favorable for tilapia farming in the Saharan environment. However, due to the unavailability of appropriate equipment, other physicochemical parameters-especially heavy metal content-were not measured. It is recommended that future studies address this limitation.
       
Although the majority of the water samples analyzed (62%) comply with national regulations, contamination by fecal coliforms, fecal streptococci and potentially pathogenic or opportunistic species such as Pseudomonas spp and Salmonella spp., was detected in 38% of the samples, specifically from tank storage water in Boukais and shallow well water in Taghit
       
These results highlight the importance of strengthening water quality management and implementing effective fish pond management practices. Special attention should be given to the reservoirs that supply the fish ponds, to ensure a safe environment for fish farming, guarantee food security, reduce disease outbreaks and ultimately protect public health.
 

Special thanks to Mr. Salhi L. and Mr. Touati T, owners of the aquaculture farms in Taghit and Nif Rhaa-Ouakda, Bechar (Algeria), respectively and to Mr. Boudani M., Manager of CNRDPA-Boukais (Bechar) for their support of this study by granting access to the farms.
     
Disclaimers
 
The views and conclusions expressed in this article are solely those of the authors and do not necessarily represent the views of their affiliated institutions. The authors are responsible for the accuracy and completeness of the information provided, but do not accept any liability for any direct or indirect losses resulting from the use of this content.
 
Informed consent
 
Not applicable.

 The authors declare that they have no conflicts of interest. No financial support was received for this research.