Journal of Aquatic Sciences

Effects of brewers’ spent grain on fecundity and gonad development of Clarias gariepinus

EYO, V.O. — 2024-09-16

The rising cost of fish feed has made farmers to search for cheaper protein sources that could be used in feeding fish without negative impacts. This study was carried out for 120 days to evaluate the effects of brewers’ spent grain (BSG) on the fecundity and gonad development of Clarias gariepinus. Six tarpaulin tanks (100 x 80 x 100 cm3) were stocked randomly with twenty (20) healthy post fingerlings of C. gariepinus with a mean initial bulk body weight of 300.20 ± 1.56 g and total length of 11.24 ± 0.18 cm. Two isonitrogenous diets (42% CP) were formulated and used to feed the fish. Diet A (control) was formulated with fishmeal as the protein source while Diet B was formulated with brewers’ spent grain (BSG) as the protein source. Water parameters of the culture systems were monitored using standard procedure. Results showed that mean fecundity of fish fed Diet A (control) (30,368 ± 428.02 eggs) was not significantly different (p>0.05) from fecundity of fish fed Diet B (30,296 ± 275.28 eggs). Also, mean GSI of fish fed the two diets were not significantly different (p> 0.05). Results obtained for mean egg diameter of fish fed Diet A (1.29 ± 0.02 mm) was not significantly different (p>0.05) from that of fish fed Diet B (1.30 ± 0.01 mm). Inference from the present study revealed that brewers’ spent grain (BSG) did not impact negatively on the fecundity, egg diameter and gonad development of C. gariepinus and is therefore recommended for possible use in aquafeed production.

Fermented bambaranut waste meal and palm kernel cake affect nutrient utilization, growth, and gut morphology of Clarias gariepinus

ENYIDI, U.D. — 2024-09-16

There is need to reduce cost of feed production using agro-waste ingredients. Bambaranut waste meal (BNWM) and Palm kernel cake (PKC) were valorized by solid-state fermentation for 7 days. Five (5) isonitrogenous (39.44% CP) and isoenergetic (2,731 kcal/kg) feeds were produced to vary in their inclusion of fermented FPKC: FBNM as followed: Feed 1, 0:400, Feed 2: 100:300, Feed 3: 200:200, Feed 4: 300:100 and Feed 5: 400:0. Fingerlings of C. gariepinus of average weight 0.176g were stocked at 15 fish per three replicate plastic aquaria per treatment feed. The catfish were fed the treatment feed ad libitum for 70 days. Fish fed Feed 2 (FPKC: FBNM, 100:300) had the best specific growth rate (SGR) of 4.04±0.05 % day-1. The fish SGR reduced with increasing inclusion of FPKC. A better SGR was recorded for catfish-fed diets with BNWM and PKC combined than diets made solely of either of the ingredients. Food conversion ratio was lowest for Feed 2 (0.80±0.02), followed by those fed Feed 1 (1.21±0.05) and then those treated with Feed 4 (1.21±0.03). Protein efficiency and conversion ratios were best for catfish treated with Feed 2. Also, catfish fed Feed 2 had the highest stomach weight, 1.62±0.09g, gut length, 16.51±0.01cm and gut weight, 2.29±0.02g. The highest contents of lysine (40.34±0.06 %) and methionine (27.30±0.01%) were recorded in Feeds 1 and Feed 2 (39.00±0.11%) and (27.02±0.08%) respectively. The high level amino acid in these feeds corresponded to high fish performances recoded.

Water quality and macroinvertebrate compositions of Obot Idim and Ikot Udo Ekpo/Akpasima Streams, Akwa Ibom State, Nigeria

AKPAN, A.U — 2024-09-16

The study determined water quality and macroinvertebrate compositions, abundance and diversity of Obot Idim and Ikot Udo Ekpo/Akpasima Streams, Akwa Ibom State, Nigeria. Water samples were collected using sterile amber bottles from the two sampling sites to measure physico-chemical parameters, nutrient loads and heavy metal contents. Aquatic macroinvertebrates were collected with the aid of a standard kick-net of D-shape with 0.5m aperture, 1 x 1 square metre with mesh size of 500 µm and was coupled to a 2m long metal handle. Samples collected from the two streams were preserved in 70% alcohol and transported to the Laboratory for sorting and identification. Results of water temperature (28.00 – 30.00oC), pH (6.60-6.80), dissolved oxygen (3.20 – 4.20mgL-1), conductivity (110.00 – 180.00 µScm-1), nitrate (0.31 – 0.43mgL-1), and cadmium (0.01 – 0.02mgL-1) from the two streams were within recommended limits for freshwater bodies, and they were significantly different (p<0.05) among sampling sites. A total of 943 individuals of aquatic macroinvertebrates were collected from the two streams. The species, Lumbricus sp., Hirudo sp., Libellula sp. Coengrion sp., Celithemis sp., Gybister sp. and Chironomus sp were among the aquatic macroinvertebrate species collected from the sampling sites. Aquatic macroinvertebrates are an important component of freshwater ecosystems and are the most widely used in monitoring aquatic ecological status. It could be inferred from the present study that Ikot Udo Ekpo/Akpasima stream was more polluted than the Obot Idim stream.

Acute toxicity of butaforce on Clarias gariepinus juveniles and impacts on haematological parameters

KEFAS, M. — 2024-09-16

The research investigated acute toxicity of Butaforce on juveniles Clarias gariepinus, and its impact on hematological parameters. Fish samples were exposed to lethal concentrations {0.00ul/l (control), 0.02ul/l, 0.04ul/l, 0.06ul/l and 0.08ul/l} of Butaforce in a static renewal bioassay for 96 hours. Fish behaviour and mortality were monitored throughout this period. At the end of the exposure time, blood samples were collected from exposed fish for haematological analysis using standard procedure. Results showed that fish in each of the toxicant concentration showed increased in physical and behavioral movement at the initial phase of exposure. Behavioral responses such as erratic swimming, loss of equilibrium, crowding in one place, rapid opercular movement, gasping for energy and air, startle responses and mucus secretion were observed. However, no adverse behavioral responses were recorded throughout the period of the experiment on the control group. Percentage mortality increased with increasing concentration of Butaforce. Significant differences (p < 0.05) in mortality indicated dose and time-depended relationship. The results of haematological study revealed the least red blood cell counts of 0.21 x 10⁶/ml in fish exposed to 0.08µl/l Butaforce concentration when compared with 6.94 x 10⁶/ml obtained in the control group. The highest white blood cell (WBC) counts of 9.92 x 10³/ml was recorded in 0.8µl/l while the least WBC counts was obtained in the control group with a value of 4.47 x 10³/ml. The lowest value of haemoglobin (1.11g/dl) was recorded in 0.8µl/l and 6.86±0.06 (g/dl) in the control. Other haematological variables followed similar trend. The 96hr LC₅₀ value was 0.024ul/l. The results of the present study revealed that Butaforce caused disruption to the physical and behavioral patterns in C. gariepinus juveniles. Thus, Butaforce could cause various toxicological and haematological effects in C. gariepinus juveniles even at low concentration of 0.02ul/.

Bioaccumulation of heavy metals in marine blue crab (Callinectes amnicola) and freshwater crab (Sudanonautes aubryi)

AJAYI, A.A — 2024-09-16

Crabs can be particularly sensitive to heavy metals because, typically, they inhabit benthic zones. In this study, selected heavy metals (Copper (Cu), Cadmium (Cd), Lead (Pb), Nickel (Ni), Arsenic (As), Zinc (Zn), Iron (Fe) and Chromium (Cr) were analysed in the organs/tissues (gills, hepatopancreas, gonads, stomach and muscle) of Callinectes amnicola and Sudanonautes aubryi samples collected from Akodo beach and Asejire reservoir respectively using Atomic Absorption Spectrophotometer. The results obtained showed that Cr had the highest concentration in the stomach of male S. aubryi (3.003 mg.kg-1) and Cu (3.016 mg.kg-1) in the gills of female C. amnicola. From the two study sites, it was observed that the concentration of As (0.064 mg.kg-1, 0.131 mg.kg-1), Cr (3.110 mg.kg-1, 1.110 mg.kg1), Cd (1.220 mg.kg-1, 1.110 mg.kg-1) and Pb (2.085 mg.kg-1, 1.003 mg.kg-1) in crabs (C. amnicola and S. aubryi) respectively were above the range of WHO acceptable limit for consumption (As 0.0001 mg.kg-1, Cr 0.050 mg.kg-1, Cd 0.003 mg.kg-1 and Pb 0.500 mg.kg-1). Input of heavy metals into the aquatic environment occurs probably through anthropogenic activities such as municipal wastewater, antifouling measures, indiscriminate use of manure and fertilizers, disposal of household and manufacturing industrial wastes. It is therefore recommended that there is a need for bio-monitoring and constant re-evaluation of heavy metals in fish and shellfish resources from the two study sites considering the status and importance of Akodo Beach and Asejire reservoir to the society.

Analysis of heavy metal accumulation in aquatic plants from River Oli, Kainji Lake National Park, Nigeria

ADELAKUN, K.M. — 2024-09-16

This study assessed the heavy metal concentrations in sediment and four selected macrophytes from River Oli, Kainji Lake National Park, Nigeria. Sediments and freshly harvested Pistia stratioties (water lettuce), Eichorrnia crassipes (water hyacinth), Nymphaea lotus (water lily), and Ipomoea aquatica (water spinach) samples were collected and labeled, processed, and analyzed for Lead (Pb), Chromium (Cr), Zinc (Zn), Copper (Cu), Iron (Fe), and Cadmium (Cd) using Atomic Absorption Spectrophotometer (AAnalyst 200). The heavy metals detected in plants collected showed the presence of all metals tested at varying concentrations. Pistia stratiotes (water lettuce) had significant high (p < 0.05) concentration of Fe (6655.18 ± 215.33 mg.kg-1), Zn (42.62 ± 3.26 mg.kg-1), Cu (3.95 ± 0.03 mg.kg-1) and Pb (1.74 ± 0.50 mg.kg-1). The level of Cr (0.006 ± 0.002 mg.kg-1) was relatively (p < 0.05) high in Ipomoea aqautica (water spinach). Furthermore, all metal elements had similar pattern of bioaccumulation (Fe > Zn > Cu > Pb > Cd > Cr) in all aquatic plant sampled. The study revealed considerable variations in the bioaccumulation potential of metals in aquatic macrophytes. It is evident from the study that all investigated plants could be an important bioindicators in the environmental monitoring assessment.

Substitution of fishmeal with solid state fermented African yam beans (Sphenostylis stenocarpa) in novel Nile Tilapia diets

ENYIDI, U.D. — 2024-09-16

Legumes are proteinous and plausible fishmeal alternative in aquafeed production. A major disadvantage of legumes is the presence of some antinutritional factors (ANF) and low content of some essential amino acids like lysine and methionine. Solid-state fermentation can remove ANF and increase the nutritional value of legumes. The African yam beans, Sphenostylis stenocarpa is a neglected proteionous legume that is vastly cultivated all over Africa and Asia. In the present study, solid-state fermented African yam beans (FAYB) was used in substituting fishmeal (FM) in five isonitrogenous and isoenergetic feeds, labeled as Feeds 1 to 5. The combination levels (FM : FAYB) were as follows: Feed 1, 400:0, Feed 2, 300:100, Feed 3,200:200, Feed 4, 100:300 and Feed 5, 0:400. A total of 270 Nile tilapia fingerlings, with an average weight of 22.64g, were stocked at 15 fish per 20 liters aquarium at three replicates per treatment. Culture water parameters were monitored. The fish were fed ad libitum three times daily for 30 days. Growth, nutritional and biochemical parameters were analyzed using standard procedure. Results revealed that tilapia fed Feed 3 had the best specific growth rate (SGR) of 3.38±0.05 %/day. This was followed by those that received Feed 4, having SGR of 2.74±0.11 %/day. There was no significant difference (p > 0.05) in SGR of fish fed Feeds 1 and 5. The results of food conversion ratio (FCR) followed similar trend as SGR. Quadratic regression analysis of growth indices against protein efficiency ratio indicated linear relationship. The best values for haemato-biochemical parameters of the tilapia were shown in Feed 3. Low values of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) were obtained in this study. This may denote that the diets were not deleterious to the gut health of the fish. Total cholesterol increased as the inclusion level of FAYB increased. Inference from the study suggests that Feed 3 (diet with equal proportion of FM and FAYB) gave the best fish performance.

Isolation and enumeration of bacteria present in Lagos Lagoon, Nigeria

BELLO, I.A. — 2024-09-16

The study was conducted to isolate and enumerate microorganisms present in Lagos Lagoon, Nigeria. Samples of water and sediment were collected during the wet and dry months from twelve selected stations (NIOMR Jetty, Atlas Copco, Sagbon Kwoji, Folawiyo Apapa, Liverpool, Ijora, Ebute Ero, Okobaba, Unilag front, American Embassy, Lekki Shoprite, and Lekki Parkview) along the Lagoon using standard procedures. Determination of bacterial loads and composition in both water and sediment samples were done using standard microbiological procedures. Results revealed the presence of heterotrophic bacteria (THB) in all sampling stations across both seasons, with the highest occurrence (1.74 x 10⁶ cfu/g) recorded in sediment sample from Ijora Station. Unilag font had the lowest microbial count of 1.32 x 10¹ cfu/g during the wet season while Liverpool recorded the highest count (3.9 x 10⁵ cfu/g) in the same season. Other seasonal results revealed mean total coliform count of 4.3 x 10¹ cfu/g, faecal coliform count of 9.04 x 10² cfu/g, Salmonella shigella count of 3.7 x 10² cfu/g and Vibro count of 6.55 x 10² cfu/g in the wet months. Results for the dry season months were 4.31 x 10² cfu/g, 6.76 x 10² cfu/g, 5.66 x 10² cfu/g and 5.41 x 10² cfu/g for total coliform, faecal coliform, Salmonella shigella and Vibro counts respectively. Generally, growth on selective media showed THB count in water to be 2.0 x 10⁵ cfu/g while that in sediment was 3.9 x 10⁵ cfu/g which were observed to increase significantly during the wet season. This increase in THB values may likely be due to changes in hydrographic parameters, flooding, and human activities like sewage dumping. The Liverpool Station consistently showed high microbial counts from the beginning to the end of the study in both water and sediment samples. Periodic environmental assessments are recommended to monitor pollution levels and conduct impact assessments.

Evaluating growth and exploitation of Tylochromis jentinki in Ikere Gorge: implications for fisheries management

ODULATE, D.O. — 2024-09-16

The present study investigated the growth dynamics, mortality rates, and exploitation patterns of Tylochromis jentinki in Ikere Gorge, Nigeria, to assess its sustainability and contribution to local fisheries. Length-frequency data were collected over two years and analyzed using the ELEFAN I and II methods. The results revealed an asymptotic length of 35.70 cm, a growth coefficient of 1.2 year-1, and a high growth performance index, indicating rapid growth but a short lifespan of approximately 2.5 years. The species exhibited two distinct recruitment periods annually, with a high exploitation rate which may suggest overfishing. The study recommended implementing management strategies, such as size limits and seasonal closures during recruitment peaks, to ensure sustainable exploitation. Protecting fish until they reach reproductive maturity is crucial for the long-term viability of T. jentinki populations in Ikere Gorge.

Assessment of heavy metals in water, sediment and some fishes from a Tropical Creek, Southwestern, Nigeria

EMMANUEL, B.E. — 2024-09-16

The study was carried out in Abule Eledu Creek to assess bioaccumulation of metals in water, sediment and some fish samples. The fish samples: Sarotherodon melanotheron (black jaw tilapia), Periophthalmus koelreuteri (mudskippers) and Chrysichthys nigrodigitatus (silver catfish) were caught with gill nets following standard procedures. Water and sediment samples were also collected along the stretch of the Creek and analyzed for five heavy metals: zinc (Zn), Cadmium (Cd), lead (Pb), copper (Cu) and nickel (Ni) using the atomic absorption spectrophotometer. The results obtained from the study showed that metal concentrations decreased in the following order: Zn >Cd>Ni>Pb>Cu for mudskipper; Zn>Cu>Pb>Cd>Ni for tilapia and Zn>Cu>Pb>Cd>Ni for silver catfish in the sampling stations. While in water and sediment samples heavy metal decreased thus: Zn>Cu>Pb>Cd>Ni for water sample and Zn >Cd>Ni>Pb>Cu sediment sample. Among the heavy metals analyzed, zinc had the highest concentrations in all the tested samples. From the data presented, it could be concluded that the values recorded for these metals were found to be below the standard tolerable limits of for food fish. Thus, these fish specimen from Abule Eledu Creek could be considered wholesome for human consumption.

Isolation and enumeration of fungal load in Lagos Lagoon

BELLO, I.A. — 2024-09-16

The study was conducted to isolate and enumerate culturable fungal population in Lagos Lagoon, Nigeria. Samples of water and sediment were collected during the wet and dry months from twelve selected stations (NIOMR Jetty, Atlas Copco, Sagbon Kwoji, Folawiyo Apapa, Liverpool, Ijora, Ebute Ero, Okobaba, Unilag front, American Embassy, Lekki Shoprite, and Lekki Parkview) along the Lagoon. All the collected samples were plated, incubated and the fungal colonies were identified using morphological characteristics. Results revealed samples collected during the dry season had the highest fungal counts both in water 2.63 x 10⁴ (cfu/ml) and sediments (2.20 x 10⁴ cfu/g) compared to the 8.8 x 10³ (cfu/ml) in water and 9.9 x 10³ (cfu/g) in the sediment recorded during the wet season. The species, Aspergillus spp, Penicillium, Yeast, and Mold were identified as the common fungal in the Lagos Lagoon. The increase in fungal activities recorded during the dry season may be attributed to the elevated temperatures and reduced water volume, resulting in less dilution of pollutants and increased concentration of nutrients, thereby fostering fungal growth. Periodic environmental assessments are recommended to monitor pollution levels, conduct impact assessments, and inform strategies for mitigating potential ecological and human health risks associated with fungal proliferation.