Nigerian Journal of Fisheries

Effects of fermented Hibiscus sabdariffa seed based diets on haematological parameters of Clarias gariepinus (Burchell, 1822) fingerlings

U. Usman — 2024-02-14

A Twenty-one week experiment was conducted to evaluate changes in the blood indices of Clarias gariepinus fingerlings fed with five Iso-nitrogenous diets with 40 % crude proteins were formulated by incorporating 0, 25, 50, 75, and 100% of fermented Hibiscus sabdariffa seed meal as a replacement for soya bean meal. A total of 150 fingerlings of C. gariepinus (weight 4.0 - 4.4g) were randomly allocated into fifteen rectangular net hapa (1 m x 1 m x 1.2 m) at 10 fish per hapa installed in a polythene lined pond (7 x 5 x 1.2 m) and fed twice daily at 5% body weight. Fish blood samples were collected to determine blood indices. The results showed that fish fed 75% FHSSM based diet had the best PCV (37.67%) while those on 25% FHSSM -based diet had the least PVC (27.00%). There were elevated values of Hb (8.93 to 13.60g/dl), RBC (2.28-2.57 x10⁶/mm³), WBC (4.15-4.38 x10³/mm³), MCV (11.72 – 14.71fl), MCH (52.81-39.60) and MCHC (34.33-47.83) for the entire treatments. Fish fed 75% FHSSM inclusion had the highest Hb (13.60g/dl), RBC (2.57 x10⁶/mm³), WBC (4.38 x10³/mm³), MCV (14.71), MCH (47.83) Lymphocytes (76.00%) and neutrophils (42.33%). The haematological parameters indicate that there was no significant difference (P>0.05) among the treatments in most of the parameters. All the indices fell within recommended ranged for healthy fish.

Constraints faced by fish farmers in Anambra State, Nigeria

Sampson O. Ohaturuonye — 2024-02-14

The major constraints faced by aquaculturists operating within Anambra State, Nigeria were investigated between the month of January, 2021 to December 2021 with a view of proffering solutions to them. A sample of 80 fish farmers were selected within the four agricultural zones of Anambra using Taro Yamani formula. Field observation, oral interviews, questionnaires and visits to farm sites were used to access the farmers. The result on socioeconomic characters of the farmers revealed that there were more male fish farmers (75.8%), average fish farmers age ranged from 41—50 years (34.7%), with majority of them being married (71.3%). They were also educated with primary education (48.8 %) and an average household number of 4 – 6 persons (60.0%). Overall mean for production constraints were (3.32), environmental constraints (3.17), socio-cultural (3.06) institutional constraints (3.40), infrastructural, financial, technological and marketing constraints were (3.72, 3.72, 3.51, and 3.32 ) respectively, and they all were above 2.5 likert scale indicating they were all major constraints. Infrastructural and financial constraints were identified as the most major constraints among all of them and ranked highest with mean range of 3.72 both among the other constraints. In conclusion, government of Anambra state is advised through the findings of this study to as a matter of urgency embark upon massive infrastructural development to stem the tide of rural- urban migration among the youths in the state as well as supporting these fish farmers with soft loans, grants, and other financial assistance in order to solve some of these identified constraints.

Seasonal variation in polychlorinated biphenyl and bisphenol a residues in Oreochromis niloticus and Hepsetus odoe from Eleyele Lake, Oyo State, Nigeria

F.E Olaifa — 2024-02-14

Fish occupy the top level of the food web in aquatic ecosystems and they are amplifiers of toxic substances present at lower trophic levels. Rapid uptake of pollutant by fish poses a potential threat to human consumers of fish due to bio-magnifications along the food chain. Polychlorinated Biphenyls (PCBs) and Bisphenol A (BPA) are chemicals of global concern, due to their persistence in the environment. These chemicals can be bio-accumulated by fish via the food chain. Therefore, this study was carried out to determine the seasonal variation of PCBs and BPA in selected fish muscles from Eleyele Lake. O. niloticus and H. odoe were procured from the fishermen at the shore of the lake. Samples were wrapped with aluminum foil, labeled, placed in a cooler containing ice, and transported to the laboratory. Fish muscles were removed; extraction and clean-up were carried out using standard procedures. H. odoe had the highest mean concentration of PCBs (81.63 ± 18.96ng/g), followed by O. niloticus (16.95 ± 8.18ng/g) and this was observed for the two species during the dry season. The mean concentration of Bisphenol A in O. niloticus during the wet season was 4.45 ± 1.08ng/g while, in H. odoe, it was 0.93 ± 0.03ng/g. the concentration of BPA and PCBs was higher than the recommended standard value. Therefore, it could affect human health.

Nutritional composition of toasted soybean, blanched and sun-dried duckweed meals used as protein sources

A. I. Abdullahi — 2024-02-14

This study was conducted to compare the nutritive values and antinutrient contents of plant protein sources such as toasted soybean meal (TSBM), blanched duckweed meal (BDM) and sun-dried duckweed meal (SDM) with the requirement for Nile tilapia feeding. Determination of all samples was done in triplicate. TSBM had significantly higher (P≤0.05) protein content (38.00%) while raw duckweed meal (RDM) had the least (35.08%). The total essential amino acid ranged from 32.77 to 41.11 g/16gN of crude protein and the total essential amino acid to crude protein content ratio ranged from 102.00 to 128.00 g/16gN. There was a significant difference (P≤0.05) in the macro mineral concentrations of all the samples except in magnesium which was not significantly different (P>0.05) in all the treatments. BDM gave the best reduction of antinutrient content by 95.26%, 92.18%, 61.47%, 33.33% and 12.50% for tannin, saponin, alkaloid, oxalate and phytate, respectively. All the nutrients in TSBM, BDM and SDM are sufficient as regards the nutrient requirement for species like Nile tilapia Oreochromis niloticus except for methionine which was the only limiting amino acid. Therefore, should these feedstuffs be considered for inclusion in the diet of such species, DL-methionine supplementation would be required to maximise production characteristics.

Assessment of biodiversity and relative abundance of fish at Tiga Reservoir, Kano: Current status

R. Audu — 2024-02-14

A study on the diversity and relative abundance of fish was conducted to determine their current status at Tiga Reservoir, Kano State, Nigeria.. The fish specimens were collected from three landing sites (Tiga, Rurum and Tarmai) between 8:00 – 11:00am with the help of artisanal fishermen using various assorted fishing gears (monofilament and multifilament gill nets). They were collected monthly from Nov. 2018 to Oct. 2019. The Relative abundance and biodiversity indices were calculated. The result shows that the reservoir harbours seventeen (17) species of fish belonging to ten (10) families, six (6) orders and seventeen (17) genera. The family Cichlidae is represented by four (4) species, the family Mormyridae is represented by three (3) species, the family Claroteidae and Alestidae each comprises of two (2) species while the family Bagridae, Clariidae, Malapteruridae, Protopteridae, Schilbedae and Cyprinidae are each represented by one (1) specie only. The most dominant family is the Cichlidae (31.36%) followed by the family Claroteidae (16.24%) and family Mormyridae (14.34%). The least is the family Protopteridae (0.03%). The most dominant species is the Coptodon zilli making up about 16.77% followed by Bagrus bajad (13.29%) while the least specie is Protopterus annectens (0.03%). Shannon weiner index (H) and Simpson index (D) of 4.0021 and 0.21903 at Site I showed that the fish were more diverse at Site I than Site II and III. Chi square (13.13) reveals a significant difference at the sites (p<0.05). This study provides an up-to-date information on the current status of Tiga reservoir with respect to the biodiversity and relative abundance of the fish species. There is the need for a frequent assessment of fish stock because population size, structure and distribution fluctuate in response to environmental variation.

Pathogenicity of Pseudomonas aeruginosa in reciprocal hybrids of Clarias gariepinus and Heterobranchus bidorsalis

O.M. Obisesan — 2024-02-14

Farming of hybrids of two African Clariid catfish species, “Heteroclarias” is becoming a focus of attention in many aquatic farms in Nigeria. Pseudomonas sp. is one of the major pathogens responsible for disease in aquaculture. A total of 150 Heteroclarias juveniles were orally inoculated with different concentrations of Pseudomonas aeruginosa ranging from 3 x 10¹ to 3 x10⁴ CFU/100μl in 4 groups (A to D) replicated thrice, for 14 days with the aim of evaluating its pathogenicity. The control group (E) also with 10 fish in 3 replicates were given normal saline orally. Clinical signs, mortality, histopathology and haematology were observed following experimental infection. Haematological parameters observed were statistically analysed using SPSS 20. Clinical signs observed in group A to C were discolouration, sloughing and patches of haemorrhage on their skin, Frequency of mortality recorded in group A to E were 20%, 10%, 10%, 6.6% and 0% respectively. Histopathological changes observed were vacuolar degeneration of renal tubular epithelium, diffuse hepatocellular vacuolar degeneration, and hyperplasia, fusion of secondary lamellae, with haemorrhage in the gills. Significant difference in haemoglobin concentration parameter was observed, translating to reduction in oxygen carrying capacity of the infected fish. Heteroclarias were susceptible to Pseudomonas aeruginosa, with resultant significant mortality.

Mycoflora of smoke-dried fish from road side table markets in Toru-Orua, Sagbama, Bayelsa State, Nigeria

B.T. Enize — 2024-02-14

Occurrence of mycoflora on smoke-dried Chrysichthys nigrodigitatus, Clarias gariepinus and Parachana obscura, obtained from roadside table marketers in Toru-Orua was studied. The fungal infestation was examined prior to the standard treatment of each fish species tissue to sterile media preparation (Potato Dexirose agar) isolation, serial dilution plating, incubation, counting isolator and inventory/identification. All the fish species examined had signs of fungal infections which include Mucor racemosus, Asperigillus fumigatus, A. niger, A. flavus and Penicillum marneffei. The specimens, P. obscura and C. gariepinus had 3 fungal isolates, whereas the C. nigroditatus had 2 fungal isolates. And the rate of infestation ranged from 4x10³/gm (A. niger) to 10 x10³/gm (Mucos racemos) in the Northern Station, while in the Southern Station the range was 2.0x10³/gm (A. falavus) to 5.0x10³/gm (A. fumigatus). Mean percentage infection was, Asperigillus spp. 87.5%, Mucor spp. 37.5% and penicillum marneffei 37.5%. Also the northern Toru-Orua roadside table market had 5 fungi isolated during the studied, while the southern Toru-Orua roadside table market had 4 fungi isolated. Though, the mean rates of infestation in the two locations were not significantly difference (P>0.05), Parachanna obscura in the North Station was found to be the most infested fish species with these three fungal isolates; Asperigillus fumigatus, Mucor racemosus, and Penicillum marnieffi. The study suggested mycoflora infestation of sold smoke-dried fish in Toru-Orua town and the need for improved handling, processing, and storage methods for the availability of safe smoke-dried fish for consumption

Moringa oleifera as feed additive in Clarias gariepinus culture: An organic water quality management technique to boost fish production

J. K Ekelemu — 2024-02-14

The study aimed at evaluating effect of using Moringa oleifera leaf to boost fish production and manage water quality was conducted in 12 weeks. One hundred and eighty Clarias gariepinus juveniles average weight (37.80g) and length (10.96cm) used for the study were distributed in fifteens into 12 tarpaulin tanks of 1m x1m x 1m and grouped into four treatments in triplicates (T1A – C to T4A – C). They were fed with commercial feed, (Blue crown), to which were added M. oleifera leaf meal (MLM) at the rate of 0g, 5g, 10g and 15g/kg of feed to give different treatment diets (T1 – T4). T1 was the control. The MLM was bound to the feed using starch. Data collected were analysed by ANOVA and Duncan Multiple Range Test (DMRT) used to separate means where there was significant difference (p<0.05). Fish were sampled fortnightly for length and weight measurement, and water samples taken to test for pH, dissolved oxygen, ammonia and temperature. Results showed that addition of 15g of M. oleifera leaf meal per kg of feed increased weight significantly (P<0.05) and resulted in reduced ammonia production. Thus use of M. oleifera at 15g/kg of feed is recommend in ponds to help improve water quality through suppressing pollution by ammonia, and consequently improving fish production.

Food security status of artisanal fishing households in Ogun Waterside Local Government Area of Ogun State

O.P. Oyetade — 2024-02-14

Majority of the fishing households in Nigeria has been associated with low food security and malnutrition, therefore, this study examine the nutritional status of fishing households in Ogun waterside local government area of Ogun state. Three communities within the selected local government were purposively selected and random selection of households, they are: Agbalegiyo (26), Ilamo (22) and Iwopin (37). A total of 85 fishing households were accessed through the use of validated interview guide. Data were analyzed using descriptive statistics and regression analysis. 45.9% of the fishers had a mean age of 50.64±12.11, 85.9% were male and married (89.4%). 62.4% of the fishers were food secure. Also, 15.3% and 5.9% indicated high food security and marginal food security respectively. Years spent in school (ꞵ = 0.032, P < 0.01), number of dependent (ꞵ = 0.970, P ≤ 0.01) and age of respondents were significant to food security index. The study concluded that years spent in school, number of household dependent and age has great influence on the food security status of the fishing households. Livelihood improvement through income diversification was recommended.