Akeem Dauda

The study was carried out to investigate the biological condition of fish species in lower Ogun River
wetlands. A total of 175 individual fish belonging to 10 species were collected from artisanal fishermen using
different types of fishing gears. Two biological indices; condition factor “K” and growth exponent “b” obtained
from length-weight relationship were used to determine the biological condition of the fishes. The condition
factor (K) recorded during the study ranged between 0.55 in Liza grandisquamis and 5.61 in Oreochromis
niloticus. The growth exponent (b) ranged from 1.48 in Penaus notialis to 5.67 in Gymnarchus niloticus. The
regression coefficient of determination was significant for some of the fish with highest value of R2=0.98 for
Sardinella madarensis. The study showed that most of the fish species in the study area are in poor biological
condition and exhibit allometric growth.

One of the factors that affect the growth and survival of cultured fishes is the stocking density. The growth and survival of African catfish (Clarias gariepinus) fingerlings cultured at three stocking densities were evaluated. Fish of mean weight 5.62g were stocked in plastic tanks with three replicates for each treatment of 425 fish/m3, 850 fish/m3 and 1275 fish/m3. The fish were fed with 42% crude protein floating pellet at 5% body weight twice daily. The best growth performance and highest survival rate was obtained in 425 fish/m3 with mean weight gain of 11.38±0.25g while 850 fish/m3 and 1275 fish/m3 had 4.38±0.32g and 3.68±0.84g respectively. The feed conversion ratio was least in 425 fish/m3 (1.67±0.87) while 850 fish/m3 and 1275 fish/m3 had 2.73±1.52 and 1.98±0.83 respectively. The mean daily weight gain of 0.27±0.01g, 0.10±0.01g and 0.09±0.02g were recorded in 425 fish/m3, 850 fish/m3 and 1275 fish/m3. The specific growth rate was also decreasing as the stocking density increases, 425 fish/m3, 850 fish/m3 and 1275 fish/m3 had 2.26±0.05%, 1.48±0.21% and 1.33±0.81% respectively. The survival rate was highest in 425 fish/m3 (83.33±2.33%) while 850 fish/m3 and 1275 fish/m3 had 50.00±4.58% and 44.33±5.12% survival rate respectively. The mean weight gain, percentage body weight gain, specific growth rate, feed conversion ratio and survival rate were all dependent on stocking density. Therefore it can be inferred that for optimal growth of fingerlings and fast production of juveniles, Clarias gariepinus should be stocked at maximum of 425 fish per cubic metre

The use of simple aeration columns is mainly aimed at solving the problem of low dissolved oxygen in freshwater culture systems at a very little cost. This study investigated the performance of three simple aerating devices in aquaculture systems. The three aeration columns tested in the experiment were upturned shower rose (USR), downturned shower rose (DSR) and perforated pipe (PEP). Each of them was fitted to the base of a 36.5 cm by 26.5 cm transparent plastic water tank. Water samples were collected and run through the aeration devices between the hours of (7:30 – 8:00 a.m.), (1:30 – 2:30 p.m.) and (7:30 – 8:00 p.m.), all the experiments were carried out in triplicates. The performance of the columns was estimated using Oxygen transfer efficiency (OTE) and Oxygen transfer rate (OTR). The highest mean daily average OTE (105.32±46.10%), was recorded in DSR followed by PEP (91.03±49.35%), while the least (72.18±40.41%) was recorded in USR. The highest mean daily average OTR (27140.26±4427.57 Kg/hr) was recorded in DSR, followed by (23277.45±4176.06 Kg/hr) in USR while the least daily average (20370.28±4425.56 Kg/hr) was recorded in PEP. All the experimented aeration columns are good for fish culture systems as they are all more than fifty percent efficient, however DSR performed best among the experimented simple aeration devices.

This paper report findings of an investigation into the effect of aeration devices on some selected freshwater quality parameters. Three aeration columns, Upturned shower rose (USR), Downturned shower rose (DSR) and Perforated pipe (PEP) were experimented. Freshwater fish culture water was passed through the devices and analysed for Temperature, pH, Alkalinity and Dissolved oxygen (DO) in the morning, afternoon and evening. The percentage modification was used to measure the effect of aeration on the selected water quality parameters. Temperature modification ranged from -2.4% to 0% with equal value in all the aeration devices at all the period, Alkalinity ranged between -10.7% and 3.7% with least modification in DSR in the morning but highest in USR in the evening, The percentage modification in pH fell between -8.3% and -1.8% with the least modification in USR in the morning while the highest was recorded also in USR but in the evening. The DO ranged between 37.1% to 161.9% with the highest modification in DSR in the afternoon and the lowest in USR in the evening. The investigated aerating devices have little effect on all the selected water quality parameters, except for dissolved oxygen where the effect is very prominent.

Most of the conventional plants used in fish feed formulation are highly competed for because they are consumed by man and used in agro allied industry, hence expensive. Therefore effort towards using plants that found limited used by man in fish feed formulation will go a long way in reducing cost of fish feed. Senna obtusifolia is a common weed of open disturbed area and is found widely in many continents of the world. Therefore this research investigated the nutritional value of S. obtusifolia seed meal as a potential ingredient in fish feed formulation. Proximate composition and amino acid profile of the seed was determined using AOAC method. Senna obtusifolia has relatively low crude protein (11.55%) but high fat content (8.00), crude fibre (14.00) and energy (2,827.16Kcal/Kg). The amino acid were very good especially the limiting amino acids, lysine (1.80) and methionine (2.11) which were found higher than that of most of the commonly used plants in fish feed formulation. Extraction of the oil and fermentation of the seed meal will definitely improve the crude protein content. Therefore further research is needed to incorporate the processed S.obtusifolia seed meal in the diet of fish and evaluate the performance of fish fed with the diet.

The study was conducted to investigate the relationships among important water quality parameters in Recirculating Aquaculture Systems (RAS) and hence predicts equation for determining some of the parameters in RAS. Wastewater was obtained from integrated pond of the University of Ibadan Fish farm and passed through bio-filtration treatment at different drying times: 24, 72 and 144hours.  The filtrates that were analyzed for using standard procedure included Temperature, pH, Dissolved oxygen, Total ammonia-nitrogen, Nitrite-nitrogen and Nitrate-nitrogen. Statistical analysis (Correlation and Regression) was used to determine the relationships among the water quality parameters and predict equation. Some of the water quality parameters were significantly interdependent. Temperature had significant relationship with all the dependent parameters but with low co-efficient of determination except with DO where the co-efficient of determination is high (R2=0.502) and prediction equation D.O=26.469- 0.784T. Temperature and pH used together had significant relationship with strong co-efficient determination (0.514 and 0.405) in relation to DO and Nitrite-nitrogen respectively with prediction equations D.O=20.547-0.787T+0.821pH and NO2-N=0.478+0.035T-0.188pH. Though temperature is a good predictor of other water quality parameters, it is encouraged to use Temperature and pH for a more reliable prediction

The study investigated the pattern of fish consumption and knowledge of fish farming in Dutsin-ma Local Government Area, Katsina State. One hundred and twenty households were randomly selected for the study. Structured questionnaire and informal interview were used for data collection. Simple descriptive statistics and multiple regressions were used to analyze the data.  Majority of respondents (87.5%) were males, 84.2% were married, 60% were within the age range of 20 - 40 years and 40.8% of them had a small household size of 1- 5 persons. Majority of the respondents (36.7%) had Arabic education. The area was dominated by civil servants (33.3%). Monthly income of majority of the households were low (< ₦20,000). However, all these socio-economic characteristics except area of residence did not affect fish consumption pattern, according to the multiple regression analysis (R2 = 10.7%), so also for knowledge of fish farming (R2 =14.2%). Despite 90% of respondents claimed they know that fish can be cultured, 69.2% do not know how to culture fish. A vast majority (91.7%) indicated their willingness to be trained on fish farming. Many respondents (64.2%) identified lack of finance as a constraint. Consumption of fish is significantly low in Dutsin-ma due to low availability of fish and inadequate knowledge of fish farming

Availability and consumption of cultured fish was investigated in three Local government areas of Katsina State and data was collected using structured questionnaires. Data obtained was analysed using descriptive statistics and linear regression. Majority of the respondents were male (88.9%) with dominant age ranged between 40-49 years. The dominant monthly income of the respondents (below N20,000) accounted for 57.4%. Most respondents (91.7%) were aware of cultured fish with only 43.5% acknowledged fish farm availability in their vicinity. Catfish was the major fish cultured while 54.6% of the respondents affirmed the availability of fish, 42.7% aware of fish sales outlets numbering up to 3 within their vicinity. Majority of the respondents (95.4%) consume cultured fish, even though mostly on occasional basis (55.4%). The greatest constraint was storage (66.7%), followed by high cost (35.2%), availability (33.3%), Taste (23.1%) and odour (23.1%). The regression analysis had R2 value of 10.1% and F-ratio 1.610, among the explanatory variables, only local government area of residence had significant influence on the availability of cultured fish. The availability and consumption of cultured fish in the study area can be regarded as low, hence the need for improving the awareness of the consumers

Global aquaculture production has been growing steadily since mid 1990s and in Africa, Nigeria is one of the significant strongly growing producers. Despite the increase in aquaculture production in Nigeria, the country still remains a net importer of fish therefore there is need for intensification and diversification. Clariids represents the major species of fish culture in Nigeria and to diversify there is need for development of the culture of other fish species. Development of Tilapia production will enhance the attainment of food security in fish production due to its positive Aquacultural characteristics. However the biological characteristics of early maturity and prolific breeding remain the major challenges in the development of tilapia culture. Though scientists have experimented different ways of managing the menace of prolific breeding but only the culture of “All male Tilapia” seems to be an effective methods of overcoming the menace. Therefore this paper reviews the masculinization techniques used in Tilapia production for preventing overcrowding of the culture medium and ensuring production of marketable sized fish. The challenges facing some of the techniques were also highlighted

The study investigated the water quality, Ichthyofauna and Macroflora diversity in view of knowing the pollution status of the wetlands around the estuaries of lower Ogun River and its environs in Kosofe/Ikorodu areas of Lagos State, Nigeria. The studied water quality indicators were; Temperature, Hydrogen ion concentration (pH), Salinity, Dissolved oxygen (DO) and Nutrient loads (Phosphate, Nitrate, Nitrite and Ammonia). Self-observation and structured interviews were conducted for 19 fishermen and 4 fishmongers to elicit information on the diversity and composition of fin and shell fish biota in the study area. Different species of Macroflora were sampled in all the study sites and samples of some closely related species were collected for identification. Water quality indicators at the sampled sites were found to range within acceptable limits for tropical water bodies except in Ogudu where the DO was slightly low and nitrite was above 0.5mg/L recommended for warm water fish species. In all, 21 fish species were reported while 10 of them were actually sighted. The dominant macroflora species include Rhizophora racemosa, Avicennia africana, Elaeis guineensis, Panicum maximum and Eichhornia spp. The study showed that anthropogenic activities influence the physicochemical parameters of lower Ogun River and this may in turn tend to affect the fauna and flora diversity of the area. However, the majority part of the wetland is still relatively healthy considering the high diversity of Ichthyofauna and Macroflora reported in the study as well as the water quality. Lastly, conservation and conscientious management of this and other wetlands in Nigeria are advocated in order to prevent their losses and corresponding forfeiture of a wide range of ecosystem services that humans derive from them.

2014. Akinwole, A. Olusegun & Dauda, A. Babatunde. This is a research/review paper, distributed under the terms of the
Creative Commons Attribution-Noncommercial 3.0 Unported License http://creativecommons.org/licenses/by-nc/3.0/), permitting
all non commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.
Global Journal of Science Frontier Research: D
Agriculture and Veterinary
Volume 14 Issue 5 Version 1.0 Year 2014
Type : Double Blind Peer Reviewed International Research Journal
Publisher: Global Journals Inc. (USA)
Online ISSN: 2249-4626 & Print ISSN: 0975-5896
Performance of Palm Kernel Shell as Nitrification Media for
Aquaculture Wastewater at Varying Drying Time
By Akinwole, A. Olusegun & Dauda, A. Babatunde
University of Ibadan, Nigeria
Abstract- Performance of palm kernel shell, a local (agricultural waste) material as biofilter media was
investigated in comparison with a commonly used synthetic injection-moulded polypropylene bioblock.
Wastewater was obtained from integrated fish culture. The biofilter media was inoculated with the
wastewater and the experiment started after 24 hrs (drying time) of inoculation. The experiment was
repeated for 72 and 144 hrs drying times. Water quality parameters measured were Temperature, pH,
Dissolved oxygen (DO), Total ammonia-nitrogen (TAN), Nitrite-nitrogen and Nitrate-nitrogen. The
efficiency of the biofilter was assessed using Percentage total ammonia-nitrogen removed (PTR) and
Volumetric total ammonia nitrogen conversion rate (VTR). All the selected water quality parameters
measured were within the range for fish culture and discharge to the environment. The highest PTR of
50.00±0.00% was recorded in PK at 72 hrs and the least (33.75±14.43%) was recorded in PP at 144 hrs
drying time. The PK had higher VTR at all the drying time with the highest VTR of
264.76±12.53mgTAN/m3d at 72 hrs drying time while the least VTR of 120.39±104.42 mg TAN/m3d was
recorded in PP also at 72 hrs drying time. The difference in VTR was significant between the two media
only at 72 hrs drying time and between 24 hrs and 72 hrs drying time in PK. The two media were able to
remove TAN from the effluent at all the drying time. The locally available PK is better than PP at all the
drying and is also available at a cheaper cost.
Keywords: biofilter media, nitrification, ammonia removal,palm kernel shell, polypropylene

Introduction of denitrification in water recirculating system to remove nitrate-nitrogen which is produced by
nitrification and tend to be toxic at high concentration has been investigated by some researchers but mostly for
temperate aquaculture and information on the time for readiness of the system is virtually not available. Therefore
this study examined the biodenitrification of aquaculture wastewater from a tropical fish species at different drying
times. Aquaculture effluent from monoculture of Clarias gariepinus was passed through nitrifying followed by
denitrifying biofilter at three drying times (24, 72 and 144 hours). Water quality parameters; Temperature, Dissolved
oxygen (DO), pH, Total ammonia-nitrogen (TAN), Nitrite-nitrogen (NO2-N) and Nitrate-nitrogen (NO3-N) were
measured in the filtrates of the nitrification and denitrification column to assess the change in water quality.
Denitrification efficiency of the biofilter was determined using Percentage nitrate-nitrogen removed (PNR) and
Volumetric nitrate-nitrogen conversion rate (VNR). The result showed that all the water quality parameters were
within the range for fish culture but the nitrate-nitrogen in the nitrification is higher than the recommended level for
discharge into the environment. The PNR recorded were 33.33±57.74%, 47.87±4.19 % and 59.09±7.87% while the
VNR recorded were 3116.88±599.60 mgNO3-N/m3d, 14125.26±746.55, 58775.51±7068.43 mgNO3-N/m3d for the
24, 72 and 144 hours drying time respectively. The study revealed that biodenitrification increases with drying time
and prevented NO3-N accumulation in the system. The incorporation of denitrification column in recirculating
system will enhance sustainable aquaculture production and save the aquatic environment from eutrophication.
KEYWORDS: Aquaculture effluents, Nitrate removal, Drying time, Total ammonia nitrogen, Recirculating system.