African Regional Aquaculture Centre Research Articles

Efficacy of Nutmeg (Myristica fragrans) as Anaesthetics in Three Life Stages of African Catfish (Clarias gariepinus)

The use of botanicals to replace as anaesthetics in fish is gaining momentum in recent years. This study was carried out to determine the efficacy of Nutmeg (Myristica fragrans) as anaesthetics in three life stages of African catfish (Clarias gariepinus). A total of 180 specimens of C. gariepinus were procured from Production Ponds in African Regional Aquaculture Centre, (ARAC), Aluu, and Rivers State of Nigeria. They were exposed to nut Meg extracts at different concentrations of 4.00, 6.00, 8.00, 10.00 and 12.00mg/L. The results obtained indicated a size related responses to nut Meg extracts. The induction time decreased significantly (P<0.05) as the concentrations of the nut Meg extracts increased. The highest induction time (15.08±0.04 min) was recorded in adult fish at 12.00mlL-1. While the lowest (3.18±0.06 min) was recorded in fingerlings at 4.00mlL However, the longest recovery time (11.59±0.06 min) was observed in the adult fish at 12.00 mg/l and the shortest (1.13±0.02) in fingerlings at 4.00mg/l of the nut Meg extracts. The recovery time for all the life stages generally increased as the concentrations of the anaesthetics increased. Also, the recovery times in adult fish were higher at all concentrations; this was closely followed by juvenile fish, while the shortest recovery time was observed in fingerlings in all concentrations of exposure. This trend followed the pattern of typical fish anaesthetics in terms of induction time and recovery time.

Lethal Effects Of Aqueous Methanol On Juvenile Tropical Freshwater Fish (Oreochromis niloticus)

In this study, juvenile tropical freshwater fish (Oreochromis niloticus) were exposed to different lethal concentrations (2.5 ml/L, 5.0ml/L, 10.0ml/L, 15.0ml/L, 20.0ml/L and 25.0ml/L respectively) of aqueous methanol and (0ml/L) which is a tank without the toxicant to serve as the control. The experiment was conducted using a static nonrenewable bioassay method. The fish were obtained from the African Regional Aquaculture Centre (ARAC), Aluu, Rivers State, Nigeria. The fishes were acclimated to an aquarium for 14 days. In order to determine the definitive test concentration, a range-finding test was conducted. The mortality, LC50s value, and the 95 per cent confidence intervals for test organisms were derived using standard procedures at 24hr, 48hr, 72hr, and 96hr respectively. There was a statistically (P<0.05) increase in the mortality rates as the concentration of the test chemical increased. The LC50 values at 24, 48, 72 and 96 hours recorded were 30.064ml/L, 26.562ml/L, 11.534ml/L, and 6.347ml/L respectively for the Chemical. The LC50 values showed that the chemical is toxic to this tropical freshwater fish. Hence, it is recommended that there should be a regulatory measure in the discharge of this chemical into the aquatic environment, to avert potential toxic effects that may result in the death of non-targeted aquatic organisms which is an edible meal for humans which in turn may affect human health.

Sex and Age-related Parasitism of <i>Clarias gariepinus</i> in earthen ponds in African Regional Aquaculture Centre, Aluu, Rivers State, Nigeria

This study aimed at investigating the sex and age-related parasitic burden of Clarias gariepinus cultured in earthen ponds. Eighty–five (85) fish samples were selected randomly for analyses from three earthen ponds. Sexing was done by the observation of the urinogenital papillae. For parasitological analysis, skin and gill scrapes were taken for external parasites while the stomach and intestines were slit open, rinsed and observed for helminthic worms. Parasites identified included; Chilodonella sp. (0.3%), Ichthyophthirius sp. (41.1%), Trichodina sp. (55%), Icthyobodo sp., (1.0%) and Gyrodactylus sp. (2.4%). From the study 31 out of 56 males and 20 out of 27 females were infected with parasites. Prevalence of infection in males and females were 55.36% and 74.07% respectively. Mean intensity of parasites was also higher for females (150.75) than for males (62.68) Chi square analysis however, revealed no significant effect (p<0.05) of parasitism on gender. It was further observed that juvenile males and early adult females respectively, had more parasites with 55.3 and 92.4 parasite mean intensities. Among age groups, the mid juveniles (25-99g) (19%), late juveniles (100-299g) (65%) and early adults (300-500g) (14%) were most infected, although there was no significant effect (p<0.05). Sex-related prevalence could be based on hormonal changes and reproduction in females, and competitive search for mates by males. Age-related infection was predicated upon active feeding habits reported among fish of these ages It is therefore recommended that routine health checks be carried out for pond cultured fish. Furthermore, that older fish be sorted and kept together, as they would have stronger immunity than younger fish.
 Keywords; Zoonoses, fish infection, late juveniles, earthen pond, Clarias gariepinus, sex, age

Single and Joint Toxicological Effect of Dispersit SPC 1000 and Bonny Oil on Mudskipper Fish (<i>Periophthalmus Papilio</i>) from the Brackish Waters of Buguma, Rivers State, Nigeria

Marine oil spillage accidents greatly impact major risks to the environment in terms of the acute and chronic adverse effects not only to the offshore, but also the coastal ecosystem. This study assessed single and joint toxicological effect of Dispersit SPC 1000 and Bonny Oil on mudskipper fish (Periophthalmus papilio) from the brackish water research station of African Regional Aquaculture Centre, Buguma, Rivers State, Nigeria. The physicochemical parameters observed throughout the study were the pH, alkalinity and salinity were 6.83 ± 0.1, 40 mg/L± 0.2 and 17,655 mg/L respectively. The temperature and Dissolved oxygen (D.O.) and specific gravity averaged 26.7oC ± 0.1, 5.70 mg/L ± 0.02 and 1.008 ± 0.001, respectively. Dispersit SPC 1000 was found to be toxic to the mudskipper at various % (v/v) concentration, above 60 % (v/v) concentration no fish survived after one hour. The relation between the probit mortality and log concentration showed a strong positive correlation between the dispersant concentration and fish mortality within 3 hours, with r2 = 0.813 p = 0.05;The lethal dose Lc50 was 73.48%. Within 6 hours, the mortality increased as the dispersant exposure concentration was increased (r2 = 0.872, p =0.05). The results of exposure of the mudskippers to the water-oil-dispersant mix (CEWAF) showed lower mortalities. Mortality was observed after 72 hours for dispersant concentration above 54 %. 63% dispersant concentrations, 20% mortalities was observed between 72 and 96 hours. Dispersit SPC 1000 alone was highly toxic, and the toxicity of CEWAF was primarily caused by the presence of dispersant. There was no joint increase in toxicity between bonny oil and the chemical dispersant, as the mixing of the dispersant by the oil resulted in diminished toxicity of CEWAF and lower mortality.Keywords: Joint Toxicity, Dispersit SPC1000, Mudskipper Fish

Microbiological quality of raw and processed farm reared periwinkles from brackish water earthen pond Buguma, Nigeria

The microbiological quality of raw and processed periwinkles obtained from brackish water earthen pond of the African Regional Aquaculture Centre, Buguma, Rivers State, Nigeria was studied. The samples were harvested at exactly 11 am on a Monday morning, at high tide and water temperature of about 29°C. Ninety samples were analyzed and used for the study, which comprised the enumeration of indicator organisms and other pathogens as well as their total counts. Total bacterial counts ofthe samples from boiled periwinkle meat, boiled shell-on periwinkles and raw periwinkle meat were

Design of water supply facilities for a tidal fish farm in the Niger Delta, Nigeria

Studies to redress the water supply problem by designing water supply facilities (inundation canal with sluice gate, a reservoir, and a pumping station) for African Regional Aquaculture Centre (ARAC) fish farm located in Aluu, Rivers State of Nigeria were carried out for twenty-four months. The topographic survey of the area indicated gentle sloping woodland, with the highest and lowest elevations of 11.00 and 1.00 m respectively above ordinance datum. The longitudinal section of the proposed canal indicated relatively flat tidally fed wetland, with the highest elevation of 1.70 m and lowest elevation of 0.47 m above ordinance datum. The mean peak heights of water in the study canal during spring tides ranged from 0.95 to 1.45 m. On the other hand, the mean peak height of water during neap tides ranged from 0.38 to 0.86 m. The floodtide and ebb tide velocities of canal water flow ranged from 0.40 to 0.75 m/s and 0.72 to 0.92 m/s respectively. Soil particles size analysis showed predominantly loamy clay soils. Mean surface water temperature readings ranged from 23.50 to 29.00 O C. Dissolved oxygen (DO) content ranged from 5.80 to 7.40 mg/L. The corresponding DO deficits ranged from 2.35 to 0.20 mg/L, indicating a moderate level of pollution. pH values of canal water flow ranged from 5.80 to 6.97 units, which is considered slightly acidic. The transparency of the river ranged from 95.00 to 199.00 cm, while total hardness values ranged from 12.90 to 50.20mg CaCO 3 /l. The water quality characteristics showed seasonal variations, attributed largely to the dilution effect of the rain. The baseline data were considered adequate for the design of water supply facilities for the farm. Keywords: Tidal water levels, fish farm, wetland, water supply, Niger Delta International Journal of Natural and Applied Sciences , 7(1): 94 - 103, 2011

Brackish water aquaculture: a veritable tool for the empowerment OF Niger Delta communities

Poverty is generally considered as one of the major causes of food insecurity and poverty alleviation is essential in improving access to food. Among countries in the developing world, including Nigeria, the people in the fishing sectors are some of the poorest and most neglected. This is true of the fishers in the Niger Delta Region of Nigeria. Depletion in natural fish stock, lack of development in the oil rich region, neglect of aquaculture industry have led to disintegration of these traditional communities. Hence, there is massive rural migration to the major cities, especially among the young school leavers seeking for greener pastures. Brackish water fish farming as a profitable alternative venture is a veritable tool that can provide food and jobs for teeming youth and women in addition to freshwater fish and crop farming. The coastal communities of the Niger Delta region has remarkable potentials for the development of brackish water aquaculture, but these remain largely undeveloped not only because of the difficult nature of the terrain, but the government as well as the multinationals have not understood and tapped the potential role of brackish water aquaculture in managing the crisis in the Niger Delta. Economic empowerment of restive youths and women through brackish water aquaculture can be achieved through encouragement of personal investments, formation of farmer co-operative societies provision of loans and credit facilities, on-farm training and establishment of brackish water fish farms by multinationals and government, manpower development in techniques for the propagation and culture of brackish water species such as tilapia, mullet, tarpon, oysters etc at centers like the African Regional Aquaculture Centre, Brackish water Research Station, Buguma, Rivers State. The above if carefully assessed and implemented could go a long way in reducing the tension in the region, thereby making it governable and enhancing economic activities which are gradually grinding to a halt as a result of youth restiveness. Key words: Aquaculture, brackish water, fish, empowerment, Niger Delta.

Effect Of Dietary Phosphorus On Protein Intake And Productive Protein Value Of Young Hybrid African Catfish (Pisces: Clariidae)

Three hundred and sixty four weeks old advanced fry of the hybrid African catfish (Clarias gariepinus (♀) x H. Heterobranchus bidorsalis (♂)) (mean weight, 1.25 ± 0.02 g) were obtained from the hatchery of the African Regional Aquaculture Centre (ARAC), Port Harcourt, Nigeria and held in 15 aerator-fitted glass tanks (55 x 30 x 30 cm3 0.05) of increasing the dietary P level on the response of fish to FFW, FCR, PI and PPV. Key words: Catfish hybrid, dietary phosphorus level, protein intake, productive protein value, protein deposition. Journal Of Agriculture And Social Research Vol. 5 (1) 2005: 18-24

Effects of Pig Manure on the Growth Rate of <i>Oreochromis niloticus</i> under integrated fish cum pig farming system

The growth response of Oreochromis niloticus (mean weight = 7.54 ± 0.91g) was determined under integrated fish cum piggery system at the African Regional Aquaculture Centre (ARAC), Port Harcourt, Nigeria. The experiment was conducted for 10 weeks between October and December 1999 in order to determine fish growth using pig manure (treatment) as compared to the use of formulated diet (control). Four ponds each measuring 1000m2 were used in the study. The ponds were stocked at a rate of 1.5 fish fingerlings/m2. Two treatment ponds each received pig manure at a rate of 10 kg daily and fish in the two control ponds were fed the formulated diet 5% of their body weight daily. Fish growth and pond water quality was monitored weekly. Mean values for specific growth rate (SGR) in control and treatment ponds were 0.73 and 0.74 %/day respectively, (P > 0.05); while the values for daily growth rate (DGR) were 0.29 and 0.24 g/day respectively. Corresponding extrapolated yields of 302 and 242 kg/ha were obtained during the 70-day culture period respectively. Key words : Fish, Growth, Integration, Manure Journal of Aquatic Sciences Vol.17(2) 2002: 85-88

Aetiology, epizootiology and pathology of ?rusty-yellow? skin discolouration of tilapia species Oreochromis niloticas and Tilapia zilii

Summary The resence of a rusty-yellow discolouration of the skin of the two tilapia species being cultured at the African Regional Aquaculture Centre (ARAC) was studied using clinical and epizootiological methods. The condition affected the tilapia species only. Ante-mortem and post-mortem examination revealed that the discolouration was restricted to the surface of the cutaneous tissue; affecting the underside of the exposed part of the scales, the fins, and the skin flap covering the scale pockets, mostly in adult fish. Microbiological and histopathological studies, as well as experimental infection trials demonstrated that a rosette-shaped, filamentous gram-positive bacterium, was the aetiologic agent. This organism was characterised as an Actinomyces species based on standard microbiological techniques. Correlation between physico-chemical parameters of the pond water and the prevalence of the skin discolouration, suggested a possible relationship to low dissolved oxygen. The prevalence of the skin discolouration was observed to increase over the 4-month culture period, being somewhat greater in a non-integrated than in an integrated culture system at harvest. Efforts to control the condition with available chemotheraeutics (mostly disinfectants and antibiotics) were ineffective although the organism was observed to ge sensitive to terramycin.

Isolation and pathogenicity of a Bacillus sp. associated with a septicaemic condition in some tropical freshwater fish species

Summary Observations made over a three-year period at the Fish Diseases Laboratory of the African Regional Aquaculture Centre (ARAC), Nigeria, revealed the gradual emergence of a new, highly infectious septicaemic condition in some widely cultivated freshwater fish species. The broad host range included: Heterobanchus bidorsalis, Clarias gariepinus, “Heteroclarias” (a hybrid of these two species, male and female respectively), Chrysichthys nigrodigitatus, and Cyprinus carpio. Clinical signs and pathological lesions associated with the condition were tyical, irrespective of the fish species affected; natural outbreaks apeared to be associated with stress due to environmental factors. The bacterium isolated from moribund and freshly-dead fishes was identified as a Bacillus sp., based on the observed cultural, morphological and biochemical characteristics. Fish reinfection trials confirmed that the isolate was the causative agent of the condition. Antibiotic sensitivity tests showed that the organism was sensitive to tetracycline hydrochloride.

Haematological studies on four catfish species raised in freshwater ponds in Nigeria

A study of the haematological and serological parameters (ethrocyte and leucocyte numbers, haematocrit, haemoglobin, blood group and genotype) is reported for four freshwater, pond-cultured catfish groups from the fish farm of the African Regional Aquaculture Centre, Aluu, Port Harcourt, Nigeria. Erythrocyte and leucocyte counts showed intra-species variability, while fish size was found to be negatively correlated to haemoglobin concentration and haematocrit values; these are significant at P = 0.05 level. The serological results obtained were found to be similar to the pattern in humans.

Composition of planktonic organisms and its associated physico-chemical parameters in two ponds at African regional aquaculture centre (ARAC) Aluu, Port Harcourt

Composition of plankton communities in two ponds at African Regional Agriculture Centre (ARAC) Aluu, Port Harcourt was undertaken between May and June 2004, to assess the composition, relative abundance and distribution of plankton. The diversity of plankton was poor. Twenty-eight taxa representing four (4) families were recorded for phytoplankton while seventeen taxa representing four families were identified for zooplankton. Chlorophyta and Cladocera were the most dominant classes in phytoplankton and zooplankton in terms of abundance, constitute 13.0% and 17.1% respectively. The water quality of the ponds is evident by high temperature (28.80C), depth (57.5cm), transparency (42), dissolved oxygen (4.9mg/l) and low BOD of (1.4mg/l). The lower density of organisms could be partly attributed due to heavy rainfall which destabilize the surface water and substrate. Hence, extensive studies of the ponds where aquatic organisms are kept should be carried out to maintain proper utilization of ponds.KEYWORDS: Plankton, composition, communities richness, abundance.