Heterotis niloticus is a fascinating freshwater fish species popularly referred to as the African bonytongue. It offers great potential for aquaculture due to its rapid growth, flesh quality, adaptability to low oxygen environments, and high market value. Domestication efforts for this species have been initiated to optimize its production and meet the increasing global demand for sustainable protein sources. This review explores the current state of H. niloticus domestication and highlights the key challenges and opportunities. Despite their promising potential, several obstacles remain, including the development of efficient hatchery techniques, optimization of feed formulations, and disease control. Overcoming these challenges is essential to promote the full potential of H. niloticus aquaculture and contribute to improved food security. Future research should focus on refining breeding programs, improving water quality management, and exploring innovative aquaculture systems. Policy support is key to driving investments, innovation, conservation efforts, and the sustainable development of H. niloticus aquaculture.

The sub-Saharan region shows fast growth in aquaculture, but current production is dominated by two species, the African catfish and tilapia. In order to support the expansion of the industry and ensure food resilience of the sector, diversification is desirable. Indeed, several candidates have been identified, among them the African snakehead Parachanna obscura. In contrast to the fast expansion of Asian snakehead farming, African aquaculture does not anticipate this trend. Still, looking at Asia, recent scientific literature provides impulses and solutions for the most pressing problems such as dry feed, cannibalism of juvenile stages and reproduction. In this review, we illustrate future research needs, integrating the recent progress in snakehead farming. Based on the recent progress in commercial diets in Clarias and protocols established for the reproduction of Channa species, an expansion of African snakehead farming seems feasible in the near future.

Aquatic habitats serve as pollutant reservoirs and experience massive pollution disasters due to anthropogenic pressure. The effect of the Water-Soluble Fraction (WSF) of burnt tire ash (BTA) was investigated on Clarias gariepinus juvenile using blood biomarkers as well as liver and gill histology. The model fish were exposed to 5 % (0.56 g/L), 10 % (1.12 g/L) and 20 % (2.24 g/L) of 96-hr LC50 (11.2 g/L) value of BTA sub-chronic doses during the experiment. Hematological indices, the liver, and gill histology were studied throughout the 28-day exposure study, which was followed by a 14-day post-exposure trial. The studies revealed that BTA-exposed fish had reduced red blood cells, packed cell volume, and hemoglobin levels with time, whereas white blood cells and leukocyte numbers increased. Concentration-dependent histopathologic abnormalities such as hyperplasia, telangiectasis, hemorrhage, desquamation, lamellar edema, and vacuolation were observed in the gill of the affected fish, in contrast to the control. Likewise, the presence of histopathologic abnormalities in the liver of BTA-exposed fish, such as vacuolar degeneration, hyperplasia, dilated portal vein, pyknotic nucleus formations, hypertrophy hepatocytes, and aggregated macrophages, was concentration-dependent. Following apparent histologic deformities that persisted in the tissues after recovery, healing from BTA exposure was only partial. C. gariepinus is an essential bioindicator of burnt tire ash’s ecotoxicological impact. Point and non-point traces of burnt-tire ash to the aquatic systems may harm aquatic animal species, thus necessitating preventative actions.

Today, fish farming has become one of the fastest-growing farming businesses, turning Nigeria into the second biggest aquaculture producer in Africa. Also, Nigeria is the leading country in the production of African catfish (Clarias gariepinus) and African bonytongue (Heterotis niloticus). The great quantity of land, inland water surface, and coastland, which are suitable for fish farming, have placed Nigeria at a very advantaged position to develop aquaculture further. Here, the development of brackish and marine aquaculture represents a promising field for future expansion. An adaptation of aquaculture development has to reduce the impact of climate change as outlined. Furthermore, disease management has to be urgently improved. Among others, the availability of commercial feed pellets is a bottleneck that has to be overcome. Unfortunately, Nigeria is far from self-sufficiency in its fish supply, with a deficit of about 2.5 million tons being imported, but national initiatives envision an expansion in the future to increase the supply of the population with high-quality protein and the prevention of malnutrition. This study identifies challenges and opportunities of the aquaculture subsector and tries to give some recommendations for future development, highlighting potential governmental interventions and support.

Aquaculture largely contributes to aquatic products and consequential dietary protein for many households. Aquaculture, just like every other food sector, is faced with enormous challenges such as unfavorable climatic events, environmental stressors and contaminants. Microplastics (MP) are emerging contaminants in aquaculture following their perturbing occurrence in cultured fish, fishmeal and aquafeed. Several MPs pathways into aquaculture facilities include wastewater, pipe-borne water, dilapidated aquaculture facilities, fish gears, and aquafeed stuff (fishmeal). Techniques for the digestion, identification and characterization of MPs are critical to understanding their pathways, bioavailability and bioaccumulation patterns in aquaculture species. The impacts of MPs on cultured fish species are identified as impaired growth, oxidative stress, neurotoxicity, reproductive toxicity, immunotoxicity, embryotoxicity, and histopathology. Bioaccumulation of MPs in tissues and biological systems have been evidenced in several cultured fishes. Mitigation efforts cum strategies such as upgrade of wastewater treatment facilities, screening of inlet pond water, screening of aquafeed stuff, regular maintenance and repair of culture facilities, could be effective to eradicate MP contamination in aquaculture. Additionally, regulatory policy on the use of plastics is key to mitigating the impact of MPs and ensure cleaner and sustainable aquaculture.

Coronavirus (COVID-19) pandemic ushered in a new era that led to the adjustments of diverse ecosystems. The pandemic restructured the global socio-economic events which prompted several adaptation measures as a response mechanism to cushion the negative impact of the disease pandemic. Critical health safety actions were impera-tive to curtail the spread of the disease such as wearing personal protective equipment (PPEs), masks, goggles, and using sanitizers for disinfection purposes. The daily de-mands for the products by individuals and medical personnel heightened their pro-duction and consumption, leading to a corresponding increase of COVID-19 wastes in the environment following indiscriminate waste disposal and poor waste management. The persistent occurrence of COVID-19 wastes aggravated microplastics (MPs) con-tamination in the aquatic ecosystem following the breakdown of PPEs-based plastics via oxidation, fragmentation, and photo-degradation actions. These MPs are transport-ed in the aquatic environment via surface runoff and wind action, apart from discrete sources. MPs' presence in the aquatic systems is not without repercussions. Ingestion of MPs by aquatic organisms can cause several diseases (e.g., poor growth, oxidative distress, neurotoxicity, developmental toxicity, reproductive toxicity, immunotoxicity, and organ toxicity). Humans are at high risk of MPs uptake. Apart from aerial and soil contamination sources, consumption of aquatic food products is a critical pathway of MPs into the human body. MP toxicities in humans include liver disorder, respiratory failure, infertility, hormonal imbalance, diarrhea, developmental disorder, and mortal-ity. Measures to alleviate the effect of COVID-19 waste litters include effective waste management plans and the adoption of technologies to extract cum degrade MPs from the aquatic and terrestrial environment.

Aquatic habitats serve as pollutant reservoirs and experience massive pollution disasters due to anthropogenic pressure. The effect of the Water-Soluble Fraction (WSF) of burnt tire ash (BTA) is investigated on Clarias gariepinus juvenile using blood biomarkers as well as liver and gill histology. The model fish were exposed to 5% (0.56 g/L), 10% (1.12 g/L) and 20% (2.24 g/L) of 96-hr LC50 (11.2 g/L) value of BTA sub-chronic doses during the experiment. Hematological indices, liver and gill histology were studied throughout the 28-day exposure study, which was followed by a 14-day post-exposure trial. The studies revealed that BTA-exposed fish had reduced red blood cells, packed cell volume, and hemoglobin levels with time, whereas white blood cells and leukocyte numbers increased. Concentration-dependent histopathologic abnormalities such as hyperplasia, bleeding, desquamation, erosion of the secondary lamellar, and vacuolation were observed in the gill of the affected fish, in contrast to the control. Likewise, the presence of histopathologic abnormalities in the liver of BTA-exposed fish, such as vacuolar degeneration, hyperplasia, dilated portal vein, pyknotic nucleus formations, hypertrophy hepatocytes, and aggregated macrophages, was concentration-dependent. Following apparent histologic deformities that persisted in the tissues after recovery, healing from BTA exposure was only partial. C. gariepinus is an essential bioindicator of burnt tire ash's ecotoxicological impact. Burned-tire trash disposed off indiscriminately may harm aquatic life, necessitating preventative actions.

Aquatic pollution may continue to deepen following the emergence of new class of toxicants. The present study investigated the effect of water-soluble fraction of burnt tire-ash on Clarias gariepinus. The fish were exposed to sublethal doses; 0.00 g/L, 2.24 g/L, 1.12 g/L and 0.56 g/L of tire-ash solution, representing 1/5, 1/10 and 1/20 of 11.2 g/L median lethal concentration (96 LC50), for 28 days, followed by 14 days recovery trial. Biological sampling was done on exposure day 1, 14 and 28, and on day14 recovery period for biochemical analysis such as the liver and gill Na+/K+ and Ca2+-ATPase, serum immunoglobulin (IgM) and brain acetylcholinesterase (AChE) of the experimental fish. Also, body biomass and behavior were evaluated. The behavioral responses exhibited by the fish to BTA exposure include reduced feeding, hypoactivity, air gulping and skin discoloration, which was observed to be concentration dependent. The body weight of 2.24 g/L and 1.12 g/L BTA-exposed fish decreased significantly than 0.56 g/L exposed fish and the control. Furthermore, findings revealed evident induction of Na+/K+ and Ca2 +-ATPase activities in both tissues, elevation of serum immunoglobulin content and inhibition of AChE activity in the brain of the exposed fish relative to the control. However, it was also observed that the biochemical parameters normalized after the recovery period. In conclusion, water-soluble fraction of burnt tire-ash produced toxicological effects in the experimental model, hence the present study provides the ecotoxicological insight of tire ash.

Food security is threatened by the global increase of human population, climate change, inequality of wealth distribution, the state of natural resources, peace and sustainability, among others. Aquaculture has become an important part of the food supply, hence contributing to food security. Sustainable fish production, which represents an important affordable protein supply, should therefore involve feed formulation and production techniques that are not dependent on fish meal as the protein source. It is on this basis that bioeconomy becomes very important to promote the resourceful use of biomass for feed, food, biomaterials, and bioenergy. This study presents housefly maggot meal as an efficient alternative protein source to fishmeal and a valuable bioresource. Clarias gariepinus fingerlings (male and female) were fed maggot meal supplemented diets for 24 weeks and we assessed their growth and gonadal development. The findings of this study revealed that maggot-meal-enhanced diets promoted growth and faster gonadal development in fish. Maggot meal represents a quality alternative protein source to fish meal and an excellent bioresource, which can help us attain sustainable aquaculture production.

The present study measured household hunger in South-East Nigeria amidst the COVID-19 lockdown. A total of 1209 households (urban and rural locations) were sampled. Household hunger was determined using the Radimer–Cornel hunger scale. Results show that before the COVID-19 lockdown, hunger prevalence in the urban areas was 85.5%, whereas prevalence in the rural areas was significantly lower, at a prevalence of 79.9% (7.3% level of association—X2 = 6.499, p = 0.012). During the COVID-19 lockdown, the prevalence of hunger in the urban areas rose to 98.0% and 99.2% in the rural areas (4.9% level of association was X2 = 2.888, p = 0.089). It was also observed that the COVID-19 lockdown significantly affected food prices. The major coping strategy employed by households was relying on less expensive foods (81.14%). High household hunger was identified as a short-term cost of the COVID-19 lockdown in South-East Nigeria. Only a few households (16.3%) benefited from the food aid programs and 16.9% from the government palliative cash transfer. It is recommended that the government setup a formidable unit that will develop physical and digital plans for effective implementation during a COVID-19 lockdown situation or other emergencies.

The present study measured household hunger in South-East Nigeria amidst COVID-19 lockdown. A total of 1209 households (urban and rural locations) were sampled. Household hunger was determined using Radimer/Cornel hunger scale, while Chi-square test was done with significance of P<0.05. Results of this study revealed 82.7% prevalence of hunger among households before Covid-19 pandemic, while during Covid-19 lockdown, hunger prevalence rose to 98.6%. It was also observed that covid-19 lockdown significantly affected food prices.The major coping strategy employed by households was relying on less expensive foods(81.14%). A genuine fear of household hunger amidst Covid-19 lockdown in south-East Nigeria was confirmed.

The safety of aquatic ecosystems has been compromised by numerous anthropogenic activities, especially leachates from non-point source toxicants, leaching into aquatic systems. This study evaluated the toxicity of the water-soluble fractions (WSFs) of burnt tire ash (BTA) on Clarias gariepinus via a battery of integrated biomarkers. Juvenile C. gariepinus were exposed to sublethal (0.56, 1.12, and 2.24 g/L) concentrations of BTA, derived from 11.2 g/L median lethal concentration (96 LC50), at duration intervals of 1, 14, and 28 days, followed by a recovery trial that lasted for 14 days. Serum biochemical parameters, antioxidant enzyme activities of the gill and liver, lysozymes activity and erythron profile were assessed. The findings of the present study revealed that BTA-WSF induced prominent alterations on biochemical parameters, lysozymes activity and antioxidant enzymes activities in the exposed fish. Furthermore, toxicant exposure promoted oxidative stress, cellular damage and genotoxicity (erythrocytic nuclear and cellular abnormalities) in the exposed fish. In general, a post-exposure trial showed partial recovery from the exposure effects of the toxicant, following the evident modifications of serum enzymes and erythron pathopathology in the experimental model. Biomonitoring of BTA, using sentinel aquatic species such as C. gariepinus, provides insights into the ecotoxicological potency of this toxicant.

This study investigated the dietary substitution effect of fish meal (FM) with cow blood meal (CBM) on growth performance, feed utilization, haematology and functions of antioxidant enzymes in Clarias gariepinus. In the test diets, FM was substituted with CBM at 7% (CBM1), 17% (CBM2), 25% (CBM3) and 33% (CBM4) inclusions. Feeding trial lasted 51 days after which the biological assays were conducted. Fish fed 7% CBM recorded better growth performance (average body weight, relative growth rate and food conversion ratio), while 33% CBM fed fish performed poorly. Incorporation of CBM in fish had no substantial effect on packed cell volume and white blood cell contents. Additionally, red blood cell count of the fish fed CBM2 decreased markedly, relative to control. When 7% CBM dietary inclusion level was exceeded in experimental feed formulation (CBM 2, 3, 4), the activities the following antioxidant enzymes: superoxide dismutase, catalase and glutathione peroxidase declined considerably, while glutathione reductase and reduced glutathione activities elevated significantly. Malondialdehyde contents elevated prominently in CBM 2, 3 and 4 groups compared to CBM1 and the control. Dietary incorporation of CBM of more than 7% negatively affected growth, feed utilization, altered antioxidant enzymes functions and malondialdehyde levels in C. gariepinus.

Climate change standard forecasts have heightened incidence of severe weather actions like floods and protracted famine. This in effect increases periodic volume of water level fluctuation in lentic water bodies thereby altering their natural composition. Too much water level variation is projected to have more serious effect on the morphology, role and biodiversity of marshy localities than effects due to increase in temperature due to change in climate pattern. This study was undertaken, to unravel specific areas and extent of water level effects on fishes. It is specifically targeted at assessing the effect of water levels on Clarias gariepinus fingerlings. The results will be useful for aquaculture as adaptation strategies are needed to contain the effect of water level fluctuation in the wild. A total of 180 Clarias gariepinus fingerlings were randomly distributed into 18-plastic tanks at 10-fish per tank for a 56-day growth trial. Growth performance, haematology and carcass composition were assessed at the end of the experiment. Results showed a significant difference (P > 0.05) in mean weight gain of fishes reared at varying water levels. The packed cell volume, red blood cell; mean corpuscular haemoglobin and corpuscular volume also showed significant differences (P > 0.05). Results indicate that water level variation has significant effect on haematology, growth and survival of Clarias gariepinus fingerlings. These results highlight the vulnerability of fish, especially Clarias gariepinus in the face of climate change.

This study investigated the effects of cow blood meal (CBM) and donkey blood meal (DBM) supplemented diets on growth and digestive enzymes activity in juvenileClarias gariepinus.Boiled blood meals (CBM and DBM) were used to substitute fishmeal at 7%, 17%, 25%, and 33% percentage inclusion levels, respectively. A total of 450 juvenileC. gariepinus(8.48 +/- 0.09 g) were randomized to nine experimental diets coded as CBD1(7%), CBD2(17%), CBD3(25%), CBD4(33%), DBD1(7%), DBD2(17%), DBD3(25%), DBD4(33%), indicating Cow Blood Diet (CBD) and Donkey Blood Diet (DBD) respectively and CT (control). Analysis from this study reveals that the protein and energy contents of boiled DBM significantly superseded that of boiled CBM. Comparative assessment based on growth biometrics of fish showed that the fish cohort fed CBD1 (7%) performed best. This was followed by the group fed DBD1 (7%) and then the control. Diets formulated with CBM and DBM, respectively, having a percentage inclusion greater than 7% undermined the growth ofClarias gariepinusjuvenile without any effect on digestive enzyme secretion.

A 56 day study was carried out to evaluate effect of temperature changes on survival, growth performance and haematology of Clarias gariepinus fingerlings fed housefly maggot meal (magmeal) diet. Ninety (90) Clarias gariepinus fingerlings, (initial mean weight 4.33±0.03g) were subjected to different environmental regulated temperature conditions in three locations (laboratory, outdoor, greenhouse). The observed average temperature was 26.53±0.01°C, 26.06±0.01°C and 31.52±0.00°C for laboratory, outdoor, greenhouse, respectively. Ten fingerlings stocked per experimental tank were fed in triplicates at 5% body weight in two portions per day. It was observed that different water temperatures affected fish growth. All experimental fish in the greenhouse died after 8 days of exposure. This happened around 14.00 hrs when water temperature reached 40°C. There was no significant difference (P<0.5) in final weight, weight gain, food conversion ratio and standard growth rate among the fish reared in the laboratory (26.53°C) and outside tanks (26.06°C), respectively. The initial carcass crude protein (Cp) value was 58.97%. At the end of the experiment fish reared in the laboratory had a crude protein value of 63.97±0.06% Cp and those reared outdoor (26.06°C) had 71.28±0.00% Cp. No significant difference in values of packed cell volume; white blood cell; haemoglobin and mean corpuscular haemoglobin concentration was found between fish reared in laboratory (26.53°C) and outside (26.06°C). However, the red blood cell (RBC); mean corpuscular haemoglobin and mean corpuscular volume showed significant difference (P>0.05). The result confirms that Clarias gariepinus fingerlings reared at a mean temperature of 26°C (within the recorded optimal temperature range for good growth) performed well. Clarias gariepinus fingerlings are not able to survive when water temperature reaches to 40oC.

This study investigated the effects of concept mapping on students’ achievement in Social Studies. The study area was Abakaliki Education Zone, Ebonyi State, Nigeria. The design of study was quasi-experimental. The sample size was three hundred and twenty (320) JSS II (Upper Basic 8) students from four different schools randomly selected from the zone. Two schools served as control groups and were taught using conventional teaching method. The other two schools served as experimental group and were taught using the concept mapping teaching method. Data were collected using a set of Social Studies Achievement Test (SSAT). Test scores were analyzed for any statistical significant difference. Result showed that concept mapping method had no effect in the mean achievement scores of students taught social studies. Also no significant difference in mean achievement scores of students in control and experimental groups was observed. However an improvement was evident in the gain score of all the experimental schools over the control schools.

This study was designed to identify level of awareness/knowledge of rice farmers in South-eastern Nigeria about climate-change; identify adverse effects of climate-variability and change on rice production and determine adaptation strategies used by small holder rice farmers within study area. Multistage purposive and stratified sampling technique was used for the sample selection. Information from 360 respondents was got using Rapid Rural Appraisal (RRA), Focus Group Discussions (FGD), and actual survey with questionnaires. Results showed that the rice farmers were aware of weather changes with grave effects on their rice farms. They reported changes in rainfall regime, intense sunshine, high temperature etc. Of special interest among the adaptation strategies by farmers are the use of inorganic fertilizers, improved rice varieties, cultivation of early maturing varieties, and proper preservation of rice seeds. This study recommends urgent measures to improve resilience of smallholder farmers in rural communities to enable them better adapt to climate-change. This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License .

A 12-week study was carried out to comparatively investigate effects of ampicillin and powdered ginger, applied as bath treatment on growth performance, haematology and serum enzymes of Clarias gariepinus. Phytochemical constituents of ginger were investigated. A total of 210 Clarias gariepinus juveniles (26.01±0.05 g and 15.31±0.10 cm) were assigned to seven treatments with three replicates each. Treatment groups had different concentrations of ampicillin and powdered ginger (250, 750 and 1000 mg/35 litres respectively) added to the culture water. Control group had neither of the substances. Fish were fed twice daily with commercial feed at 5% body weight for 12 weeks. Result for growth revealed that there was significant difference (p˂0.05). Result for haematology studies revealed that there was significant difference (p˂0.05) between ampicillin and ginger treatments. There was no significant difference (p˃0.05) in aspartate amino transferase (AST) and alkaline phosphatase (ALP) between treatment groups. However, significant decrease in alanine-amino-transferase (ALT) was seen in 250 mg and 1000mg ampicillin treatment groups. Ginger can conveniently be used in place of ampicillin.

Response of Clarias gariepinus to diets of African yam bean (Sphenostylis stenocarpa) (AYB) subjected to two processing methods was assessed. Mature AYB was boiled, fermented and processed into meals. Seven diets were formulated to contain 44.07 ±0.48% crude protein and 19.03±0.05 kJ g-1 gross energy respectively. Fishmeal in the diets was substituted with each of the two processed AYB meals at 40%, 45% and 50% levels. Nine fingerlings (initial average weight 1.36±0.02g) were stocked per experimental tank. Experimental diets were fed to triplicate groups of catfish fingerlings at 10% body weight for 56 days. Results showed that specific growth rate (SGR) and protein production value (PPV) were highest at 45% replacement of fermented AYB (3.32±0.20; 49.30±17.94) compared to control (3.17±0.44; 38.89±12.49). Mean values for haematological parameters (PCV, HB, WBC and RBC) significantly increased (P<0.05) above the initial status and control group. Haematological values for fish fed 40% inclusion level of fermented and boiled AYB were the highest. This study shows that AYB processed by fermentation and boiling were effective in enhancing fish growth. However, based on SGR and PPV results Fermented AYB should not be used in Clarias gariepinus diets beyond 45%inclusion level.Key Words: African Catfish, Alternative Protein Sources, African Yam Beans, Haematology