Application of anaesthetics in fish hatcheries to promote broodstock and fish seed welfare in Zambia

Abstract

This study investigated the application of anaesthetics in 23 private and government-owned hatcheries in 10 provinces of Zambia. The study employed both qualitative and quantitative research designs and used a structured questionnaire to collect data from the respondents. The results showed that most hatcheries (65%) were not using anaesthetics in handling fish and all (100%) that were using anaesthetics (35%) used clove powder as the only type. Most respondents (61%) were not sure or did not have information about the availability of the anaesthetic substances in their localities while only 26% reported wider availability but 13% had a divergent claim. The mortality rate for fingerlings in hatcheries that applied anaesthetics ranged between 15–30% with consistently high demand while those that did not use anaesthetics reported mortality rates of more than 50% and had low demand. The majority of the respondents (53%) had received training up to certificate level, followed by those who had attained up to a diploma qualification (27%) while those that attained up to a degree (13%) and general skills (7%) levels were in the minority. Furthermore, most respondents (35%) did not know the importance of fish anaesthetics. We conclude that the use of fish anaesthetics in Zambian hatcheries is very low and could partly be the cause of high fingerling mortalities, and there is an urgent need to address the situation.

Keywords:

• Anaesthetics
• fingerlings
• fish hatcheries
• stress management
• fish handling
• Zambia

Public Interest Statement

In the face of declining fish catches in the wild and an increasing human population, aquaculture is expected to play a pivotal role in supporting human life through income, employment, and most importantly food needed for livelihood. However, sustainable aquaculture is expected to be partly hindered by inappropriate stress and welfare management of farmed animals especially in hatcheries where broodstock and fingerling are exposed to various stressful situations. One fundamental way of managing stress in hatcheries is by using anaesthetics. Therefore, this study surveyed hatcheries in Zambia to find out the extent to which anaesthetics are used in daily routine practices. This information is crucial for improved quality of fish seed which will consequently contribute to increased fish production in a sustainable way while maximizing animal welfare which has become extremely vital to consumers especially in both developing and developed countries in the recent past.

1. Introduction

In 2018, the global fish output was reported to be around 179 million metric tons and 88% of this production was used for human consumption as a source of protein (Pauly & Zeller, 2017; Food and Agriculture Organization [FAO], 2020; Maulu et al., 2020, 2022). However, the contribution of Africa to global aquaculture production was estimated at 2.7% and this is described as insignificant and a mystery given the abundant water resources that the continent is endowed with which have the potential to propel the aquaculture sector forward (Halwart, 2020). In addition, despite the continent receiving massive support in terms of finances from numerous donors, the performance of the industry still remains below par while Asian countries which receive less donor funding are able to produce 1000 times more fish than Africa (Brummett, 2007; Obwanga et al., 2020). In the recent past, several countries such as Egypt, Nigeria, Uganda, Ghana, Tunisia, Kenya, Zambia, Madagascar, Malawi, Mozambique and South Africa have shown some progressive growth and production from the aquaculture sector (Adeleke et al., 2020; Hasimuna et al., 2019, 2023; Maulu et al., 2019; Muhala, Chicombo, et al., 2021). However, some of the major constraints to more robust aquaculture development in the continent is the continued inadequate supply of good quality fish seed and feed when needed (Hasimuna et al., 2019; Moyo & Rapatsa, 2021; Muhala, Rumieque, et al., 2021), and these are key requirements for successful aquaculture production and productivity (Musyoka & Mutia, 2016). As a result, most fish farmers have no access to the required quantity or the right quality when and where they need them (Brummett et al., 2008; Musyoka & Mutia, 2016). Despite Zambia being one of the top ten aquaculture-producing countries on the continent, the challenge of poor quality and low quantities of fish seed has been a real challenge for the country and the Department of Fisheries in particular (Hasimuna et al., 2019). This can be attributed partly to poor or lack of stress avoidance in the hatcheries run by both private and government. In fish hatcheries, handling broodstock in routine activities usually causes physical, chemical and social stress (Chandroo et al., 2004). This stress is reported to have negative effects on the brood fish such as impaired reproductive performance, reduced egg size and sperm count, ovarian resorption of eggs, delayed ovulation, increased developmental abnormalities and reduced size and survival of offspring (Maeda & Tsukamura, 2006). Furthermore, if stressors are severe or long-lasting and the fish is not capable of regaining homeostasis, then the responses themselves may turn out to be maladaptive and threaten the fish’s health and well-being (Hasimuna, Maulu, et al., 2020; Maulu, Hasimuna, Mphande, et al., 2021; Mphande & Chama, 2015; Siavwapa et al., 2022; Wu et al., 2017). Therefore, to improve the reproductive performance of valuable broodstock and improve seed production, stress must be minimized and fish selected based on their ability to better cope with stress (Vera et al., 2011). In aquaculture facilities, stress and mortalities cause substantial losses of production and resources because stress is usually linked to disease outbreaks (Small & Bilodeau, 2005). Fish welfare in farming facilities is usually compromised by stress, and stress management has received a lot of attention from fish culturists and consumers in the recent past (Alonso et al., 2020; Husen & Sharma, 2014; Kells, 2022). As a consequence, anaesthetics are used in aquaculture to prevent stress, physical injury and reduce metabolism, and to immobilize fish for easy handling during harvesting, sampling and spawning procedures (Hasimuna et al., 2021). Hatcheries occupy a strategic position on the aquaculture value chain and without proper stress management of broodstock fish, the quality and quantity of fish seed will continue to be a constraint (Migaud et al., 2013). However, the extent to which anaesthetics are used to minimize stress during the routine handling of fish in hatcheries in most developing countries like Zambia is not known (Gabriel et al., 2020; Hasimuna et al., 2021). Therefore, this study aimed to establish the extent of anaesthetic use, types, availability, their effect on both the mortality rate and demand of fingerlings, the relevance of training to the job and reasons for not using anaesthetics in Zambia.

2. Materials and methods

2.1. Study area

The data were collected throughout Zambia, a country in the Southern part of the African continent with an area of 752,614 Km² lying between 8° and 18° latitude and 22° and 34° longitude (Maulu et al., 2019). Administratively, the country is divided into 10 provinces which are further subdivided into a total of 116 districts. The country has abundant freshwater resources suited for promoted aquaculture production (Hasimuna et al., 2019; Nsonga & Simbotwe, 2013). The estimated total number of small-scale fish farming households was 9,615 and 126 large-scale farms in Zambia according to the 2017/2018 Livestock and Aquaculture census (Zambia Statistics Agency, 2023). Zambia has at least thirty fish hatcheries dotted across the country and this number has kept rising due to the growing interest in fish farming. In the past five years, the Government of the Republic of Zambia with the support of the African Development Bank has been promoting fish production (i.e. both fish seed and table fish). Several youths and women were trained so that they could establish and manage fish hatcheries so as to meet the fish seed deficit in the country.

The main production systems used are extensive, semi-intensive and intensive with ponds making the most production units. The purposive selection of Zambia and its districts for the study area (Figure 1) adheres to the area sampling approach advanced by Sekaran and Bougie (2016), and Pickens et al. (2020). Figure 1 shows the location of the ten provinces of Zambia with districts and hatcheries under investigation in this study.

Figure 1. Map showing the ten provinces and the districts where the sampled hatcheries are located.

2.2. Study design and data collection

To achieve the objective of the study, both primary and secondary data were collected from 18 districts of Zambia indicated in the map (Figure 1). Primary data was obtained using a structured questionnaire with three sections (A, B and C) covering the demographical and economic data of respondents (A), hatchery information (B) and anaesthetics use (C) between March and June 2022 after pre-testing and modifications to the questionnaire (Muhala, Rumieque, et al., 2021). Pre-testing was done to evaluate the questionnaire’s clarity, strengths, and shortcomings as well as to see if it would yield the desired results. The questionnaire was changed to improve clarity, eliminate redundant questions, and reduce ambiguity after the pilot testing found several of the items were repetitive. Adult males and females over the age of 18 years who owned or were managing fish hatcheries and were involved in the fish farming business in any age category qualified as respondents. All respondents provided informed verbal agreement before being interviewed. The enumerators conducted the interviews in English and translated them into the participants’ native languages such as Bemba, Nyanja, Lozi and Tonga for those who were unable to communicate in English.

The use of both secondary and primary data was critical to the triangulation and strengthening of the research goals and insights. Further triangulation and validation were done through an FAO workshop. This also made sure that the objective under study was correct and valid. As a result, a total of 23 hatcheries were purposefully selected based on their attendance at a training workshop on hatchery management that the Food and Agriculture Organization of the United Nations (FAO) Zambian Office organized in 2021 in conjunction with the Department of Fisheries and took place at the National Aquaculture Research and Development Centre (NARDC) in Copperbelt Province, Kitwe District. Hatcheries that did not take part in the training were excluded from the study but these were few because the majority and main hatcheries in Zambia had taken part in the training making the sample size of 23 hatcheries sufficient for the study. These hatcheries were raising three spotted Tilapia (Oreochromis andersonii), the Green-headed Tilapia (Oreochromis macrochir), the Red-breasted Tilapia (Coptodon rendalli), Tanganyika Tilapia (Oreochromis tanganicae), Clarias gariepinus, Cyprinus carpio and Oreochromis niloticus. Furthermore, literature relevant to the study was used as secondary data (Muhala, Rumieque, et al., 2021; Siankwilimba et al., 2021), covering a period from 2016 to 2022. The study combined both qualitative and quantitative research designs but weighed high on qualitative than quantitative design (Qual-Quan) (Cresswell et al., 2013) and this design was borrowed from Creswell (2019) and many other scholars (e.g. Kliueva & Tsagari, 2018; Suhaimi et al., 2022; Toledo-Pereyra, 2012).

2.3. Data analysis

The primary researcher manually coded and imported the survey data into Microsoft Excel® 2007 to standardize it and make it easier to handle and analyse. Data were exported to Statistical Package for Social Sciences (SPSS) version 22 for additional clean-up, removal of redundant variables, and preliminary analysis using descriptive statistics after an initial data clean-up in Microsoft Excel® using the filter function (checking the codes and respective cells for missing variables and wrong codes). Some mistakes and missing data were discovered in some cells during the preliminary analysis. In order to make the data set clean and suitable for additional studies, this required additional clean-ups (wrong codes and transposed figures). The data analysis process began with tabular and graphical assessments of the data. Descriptive statistical tables for scale variables and frequency tables for ordinal and nominal variables were produced.

3. Results

3.1. Demographic information of the respondents

The demographic information of the respondents in the present study is shown in Table 1. As can be noted, the majority were males accounting for 65% of the total. Five main positions at work for the respondents who practically worked in hatchery operations were identified and include, in the order of majority, managing director (30%), aquaculturist (17%), farm manager, hatchery operator, fisheries/aquaculture assistants, and those that did not disclose all recorded the same percentage (13% each). Interestingly, most of the respondents (61%) had not received relevant training in line with their job position. Furthermore, 65% of all the respondents were not applying any anaesthetic substances at their farm for any fish handling.

Table 1. Demographic information of the respondents

Category	Variable	Number	Percent (%)
Gender	Male	15	65
	Female	8	35
Position	Aquaculturist	4	17
	Farm manager	3	13
	Managing Director	7	30
	Hatchery Operator	3	13
	Aquaculture/Fisheries Assistant	3	13
	Others	3	13
Relevant training	Yes	9	39
	No	14	61
Use of anaesthetics	Yes	8	35
	No	15	65

3.2. Type of anaesthetics used

Among the many potential anaesthetic agents used in aquaculture, the common ones are tricaine methane‐sulfonate (MS 222), carbon dioxide (CO₂), sodium bicarbonate (NaHCO₃), Clove oil and quinaldine sulfate. Interestingly, only clove powder was reported to be used by hatchery operators. The rest of the anaesthetics were never used except for Sodium bicarbonate which was reported to have been used for research purposes at two government hatcheries.

3.3. Availability of anaesthetics

Information regarding the availability of anaesthetic substances in the communities where the hatchery owners reside is summarized in Figure 2. Unfortunately, most were not sure or did not have information about the availability of the anaesthetic substances in their localities. Only 26% of the respondents reported that the anaesthetics were widely available while 13% had a divergent view.

Figure 2. Responses on the availability of anaesthetics in communities.

3.4. Relationship between anaesthetics use and fingerling mortalities

The relationship between using anaesthetics and the mortality of fingerlings at the hatchery is presented in Figure 3. The highest mortality rates experienced by the hatcheries that applied anaesthetics were in the range of 15–30%, while those that did not use anaesthetics experienced higher mortality rates (>50%).

Figure 3. Effect of anaesthetic use on mortality rates of fingerling.

3.5. Relationship between anaesthetic use and demand of the fingerlings

The demand for fingerlings in relation to anaesthetic use is summarized in Figure 4. The results show that the demand for fingerlings in hatcheries where stress management is done during handling was consistently high.

Figure 4. Effect of anaesthetic use on fingerling demand.

3.6. Relevant training to the job

In this study, it has been established that only 39% of the respondents had received pieces of training relevant to their job (see Table 1), the specific types of training received are summarized in Figure 5. Of this proportion, the majority (53%) had obtained up to a certificate level, followed by those who had attained up to a diploma qualification (27%) while those that attained up to a degree (13%) and general skills (7%) levels were in the minority.

Figure 5. An overview of the educational and training status of the respondents in relevant courses.

3.7. Reasons for not using anaesthetic during fish handling

The study showed that the majority of the respondents in the present study were not applying anaesthetics in their fish handling during their routine farm activities (Figure 6). Most respondents (35%) disclosed that they did not know the importance of using fish anaesthetics, 23% indicated that they lacked information on required application levels for different fish species, 18% did not see the importance of using anaesthetics in the handling of fish, another 18% bemoaned the high costs incurred when purchasing fish anaesthetics agents, and 6% reported that they did not even have access to fish anaesthetics due to unavailability in their community.

Figure 6. Reasons of the respondents for not using anaesthetics in routine fish handling.

4. Discussion

The broodstock in aquaculture is usually subjected to stress during handling, transportation and other routine procedures (Hasimuna, Monde, et al., 2020), which can have a tremendous negative impact on the reproduction performance, egg size, quality of offspring, and delayed ovulation, among others. To prevent this, fish are anesthetized making them lose their irritability and the ability to feel pain. Coyle et al. (2004) and Neiffer and Stamper (2009) reported that the use of anaesthetics in fish can minimize stress, reduce handling trauma, and minimize the movement of the fish. Anaesthetics can be applied to fish by placing them in an anaesthetic bath containing the right concentration of the drug where the fish will absorb it through the gills and spread it to the rest of the body through the bloodstream (Coyle et al., 2004).

In the current study, the results showed that the operations of fish hatcheries are mainly dominated by males as compared to females. This is consistent with the finding of Ashley Dejo et al. (2016) who reported that more men were operating fish hatcheries in the Oyo State of Nigeria than women were. Similar findings were also reported by Raufu et al. (2009) who conveyed that men dominated the aquaculture industry compared to women. The disparity in gender participation has been attributed to various challenges that women face bordering on cultural, social, economic, access and control over properties and resources (Gonzalez Parrao et al., 2021). However, it must also be noted that the present study did not investigate the owners of the farms during the interviewers, which suggests that some farms could be owned by females who then employ male workers.

Despite the relevance of avoiding stress in routine hatchery operations, the application of anaesthetics in fish hatcheries in Zambia is quite low and can be a major cause of low fish seed quality and high mortalities contributing to lack of good quality and quantity fingerlings in the nation (Hasimuna et al., 2019). Inadequate stress management will continue to have a retrogressive impact on aquaculture development in Zambia because the quality of fingerlings and good hatchery management practices like the use of anaesthetics plays a pivotal role in aquaculture (Hasimuna, Monde, et al., 2020). As a good number of respondents indicated a lack of knowledge regarding the use of anaesthetics, there is a need to educate the farmers on the importance of maintaining animal health status during routine handling procedures.

Concerning the type of anaesthetics that are used in the hatcheries in Zambia, clove powder was the only reported anaesthetic in use. This is because most users are only familiar with this type of anaesthetic even though the dosage needed for different stages of indigenous species is not clearly known. This is in line with what was reported in other studies Hasimuna, Monde, et al. (2020); Gabriel et al. (2020); Hasimuna et al. (2021), indicating that availability and accessibility are some of the key factors in choosing anaesthetics. However, regarding the types of anaesthetics, the results of the current study do not agree with the findings of Zahl et al. (2012) and Schroeder et al. (2021) who found that tricaine was the main anaesthetic used in aquaculture, especially in European countries. Additionally, the current study further revealed that clove powder was not used necessarily to reduce stress in routine operations but only for artificial breeding and research mostly in government research stations. This again stems from the lack of knowledge that anaesthetics can be used for many routine aquaculture practices that involve the handling of fish not only for breeding and artificial propagation purposes. This meant Oreochromis species especially brooders that breed naturally without manipulating them artificially were exposed to stress in most if not all the hatcheries because routine aquaculture procedures such as handling, netting, crowding, confinement and live transport are known to evoke a stress response in fish (Siavwapa et al., 2022). This stress can predispose the fish to diseases and disease-causing pathogens. As such, the use of anaesthetics in aquaculture has been emphasized by several researchers as a way of reducing stress due to aquaculture activities which may predispose the fish to diseases due to weakened immunity (Hasimuna, Maulu, et al., 2020; Neiffer & Stamper, 2009; Siavwapa et al., 2022). Although clover powder use was reported, its availability is very challenging as it is used heavily in the food processing industry (i.e. it is a predominant spice in sausages) and generally used as a spice in many other foods. Because of this, clove powder runs out of stock quickly in supermarkets and retail shops making its availability unreliable. Lack of sensitization programs by the government offices or other stakeholders in charge of the aquaculture sector on the available alternative anaesthetics and best practices of fish handling can also be a factor contributing to people’s ignorance about the subject matter. Therefore, more research on potential anaesthetics agents in Zambia, as well as other developing countries, is required. There is also a need to sensitize hatchery owners about the anaesthetic potential of NAHCO₃ which is cheaper, safer and readily available throughout the country where it is used for baking purposes (Hasimuna, Monde, et al., 2020; Siavwapa et al., 2022).

Furthermore, there were alarming levels of unsureness about the availability of anaesthetics in localities of fish hatcheries in Zambia among the respondents. It is therefore not surprising that there was a low application of anaesthetics, suggesting that farmers require information before adopting new practices (Maulu, Hasimuna, Mutale, et al., 2021). The lack of know-how about the availability of anaesthetics could be attributed to the fact that those using these anaesthetics were located along the rail line (urban areas) and this skewed availability may accelerate the growth of fish farming and observance of the requirements to handle fish in a humane way in certain areas of the country. Additionally, the predominant anaesthetic available was clove powder which is mostly found in supermarkets along the line of rail (Hasimuna, Monde, et al., 2020), while other anaesthetics like tricaine and clove oil were not available in Zambia just as observed in other earlier studies (Hasimuna et al., 2021; Hasimuna, Monde, et al., 2020; Siavwapa et al., 2022). This could be attributed to high prices coupled with the stringiest importation laws of chemicals in Zambia, and the fact that tricaine and clove oil have no other competitive usage in the country. Moreover, the use of anaesthetics to a large extent will depend on the knowledge of the availability of these substances and their costs as well as the importance attached to daily hatchery operations.

When focusing on the relationship between anaesthetics use with fingerling demand and mortalities there was a relatively high demand for fingerlings from fish hatcheries where anaesthetics were used in comparison to those that did not. This high demand may be due to the good reputation of having quality fish seed both by growth and survival rate. On the contrary, low to average demand in non-anaesthetic users is due to low-quality fingerlings in terms of growth and survival rate as a consequence of poor stress handling. Additionally, the high demand observed for non-anaesthetic users is due to fish farmers’ lack of options especially in areas where access to quality fingerlings mainly from government hatcheries is not possible or would be too expensive due to transportation costs. This leaves fish farmers with no alternative sources of fish seed in their areas but to buy the same low-quality fingerlings. As a consequence, this leads to the high cost of fish farming due to hidden costs through extended feeding periods owing to poor growth and high mortality rates of low-quality fingerlings procured. This has the potential to discourage farmers as they may think that aquaculture is not lucrative because growth and survival rate are critical factors for those that are practising aquaculture as a business and may negatively impact aquaculture growth in Zambia. It’s not surprising that anaesthetic users had low levels of mortalities and non-users had high mortality rates because stress management through anaesthetic use is known to reduce mortality in the routine handling of fish (Carter et al., 2011). Concerning the relevance of training, it was discovered that those with academic qualifications were in government research institutions which are attributed to the need for a formal qualification in either fisheries or aquaculture to be employed as aquaculture assistant, aquaculture technician/aquaculturist and aquaculture researcher. This could be the main reason behind the good quality fish seed produced in these hatcheries because animal welfare and stress management of farmed animals are prioritized. These institutions can be utilized as dissemination centres for anaesthetic applications to others due to their strategic locations across the country and will help to advance the aquaculture sector in Zambia through the appropriate running of hatcheries with regard to stress management and animal welfare. This is in line with the findings of Veliu et al. (2009) who found that most aquaculture technicians were employed by the government. This is because skilled and unskilled individuals want government jobs due to job security and less restrictive working hours which give them the liberty to do other part-time work to earn extra income.

Furthermore, the study revealed a lack of knowledge among most hatchery operators on the use of anaesthetic agents which can be used for many routines of aquaculture practices including the selection of broodfish, sorting and pairing (Topic Popovic et al., 2012; Haihambo & Gabriel, 2022; Hasimuna et al., 2021; Hasimuna, Monde, et al., 2020; Siavwapa et al., 2022) and this was one of the major reasons for not using anaesthetics during fish handling. Similar findings were reported by Yang et al. (2021), who stated that anaesthetics were not frequently used in the routine handling of food fish due to a lack of knowledge of their importance. Likewise, the lack of information on the required dosages for indigenous fish species constrained the use of anaesthetics in Zambian hatcheries, and knowledge must be generated for hatchery managers and fish culturists if stress management and fish welfare are to be advanced (Trushenski et al., 2013). This is vital because failure to use a specific dosage may result in stressing the fish instead of mitigating the same by causing abnormal metabolic pathways, suboptimal oxygen consumption and many other physiological alterations (Hasimuna et al., 2021; Hoseini & Ghelichpour, 2012; Pattanasiri et al., 2017; Topic Popovic et al., 2012). Moreover, other factors limiting the application of anaesthetics were the high cost of anaesthetics while others just felt that using anaesthetics was not necessary due to the species they were breeding which did not require artificial breeding like Clarias gariepinus or cyprinid species. Interestingly, hatcheries that indicated that they were using anaesthetics were government-run Research stations. This is ascribed to their involvement in research and the artificial propagation of Cyprinus carpio and Clarias gariepinus. Furthermore, these institutions value animal welfare and the need to reduce fish stress. This is because government-run hatcheries are managed by people with advanced training in fisheries and aquaculture as such they appreciate the use of anaesthetics when handling aquatic animals.

5. Conclusion and recommendations

The application of anaesthetics in fish hatcheries to promote broodstock and fish seed welfare in Zambia has been investigated. The study has established that the use of anaesthetics in routine hatchery procedures and activities is low, especially among privately owned fish seed producers. The study also revealed that clove powder was the only anaesthetic in use mainly among government-run hatcheries. Some of the constraints to the use of anaesthetics in hatcheries included high cost or unaffordability, inaccessibility, unknown dosages and lack of understanding of the importance of anaesthetics in stress management. Given the importance of stress management in hatcheries, we recommend an enhanced application of anaesthetics in hatcheries. We recommend utilizing locally available and cost-effective chemicals like sodium bicarbonate, particularly for species like Oreochromis macrochir whose appropriate dosage has been established. We also acclaim establishing the appropriate dosage for other indigenous species such as Oreochromis andersonii, Coptodon rendalli and Oreochromis tanganicae which are important aquaculture species in Zambia and are produced in most hatcheries. Additionally, we recommend expediting the certification of both private and public fish hatcheries so that appropriate fingerling and broodstock standards set by the Zambia Bureau of Standards can be adhered to. Furthermore, research is needed to assess the effect of clover powder on the haematological and biochemical parameters of indigenous tilapia species. Lastly, we recommend investigating the efficacy of various potential plant sources of anaesthetic substances especially in far-flung areas where clove powder is not accessible.

Author contributions

JM generated the idea, defined the objectives, and coordinated sample collection and the writing of the manuscript. OJH assisted with data collection and in defining the objectives and participated in writing the manuscript. SM assisted with statistical analysis and participated in the writing of the manuscript; DP, VM and CM critically reviewed and made substantial contributions to the manuscript. EK, ES, KN, BMH, CJP and SS participated in writing the manuscript. All the authors read and approved the final manuscript.

Acknowledgments

The authors wish to thank Mr. Chad Kancheya for the support rendered during data collection.

Disclosure statement

No potential conflict of interest was reported by the authors.

Data availability statement

All the necessary material is contained in this article.

Additional information

Funding

This study did not receive any funding.

Notes on contributors

Joseph Mphande

Joseph Mphande is a Fisheries Officer at the Zambian Department of Fisheries with over six years of work experience in the aquaculture and fisheries industry. His research interests are in fish health and welfare management, fish anaesthetic, aquaculture production, ecological and carrying capacity modelling of aquaculture, fish hatcheries, aquaculture and environment, fisheries management, morphometrics and meristic measurements, fish diseases, fish genetics, climate change, heavy metals, microplastics and their impacts on aquatic biota. This study fits into animal welfare and stress management which will contribute to sustainable aquaculture development in Zambia and beyond.