Marine Sciences-Scholarly Publications

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    Open Access
    Physico-Chemical Parameters and Ichthyofauna Composition of Oyan Dam Area, Ogun State, Nigeria
    (West African Journal of Fisheries and Aquatic Sciences, 2020) Osibona, A.O; Ayoola, S. O
    The surface water physico-chemical characteristics and ichthyofaunal composition of Oyan Dam and its environment were investigated monthly between December, 2017 and August, 2018. The surface water temperature, pH, Total Dissolved Solids (TDS) were measured in-situ with a portable Hanna TDS/pH meter -(HI9813-6). The Dissolved Oxygen (DO), Biological Oxygen Demand (BOD), Chemical Oxygen Demand (COD), Phosphate, Nitrate, and Nitrite were determined in the laboratory using standard methods. The monthly total rainfall, relative humidity, and air temperatures were obtained from world weather online/Abeokuta weather. Fish abundance (ichthyofaunal composition) was determined by monitoring and recording the catch from fishermen. The pH ranged between 6.9-8.2, 7.2-8.3, and 7.0-8.2 in Apojola, Dam site, and Ibaro respectively. Highest DO 7.86mgL-1 and lowest 4.2 mgL-1 were recorded in the Dam site in April and July. Eighteen fish species belonging to ten families were encountered in the study. The family Cichlidae contains more fish species than any other family. Ichthyofauna species recorded were Oreochromis niloticus, Tilapia guineensis, Sarotherondon galilaeus, Tilapia mariae, Tilapia zillii, Chrysichthys nigrodigitatus, Sarotherondon melanotheron. Chrysichthys nigrodigitatus was the most abundant (16%) and occurred throughout the sampling period. The least abundant species (0.05%) Parachanna obscura, occurred only in December and January. The study revealed that Bagridae represented by Chrysichthys nigrodigitatus contributed to the highest number of fish. The physico-chemical parameters are within the range for culturable species. Nigeria can derive a substantial proportion of its fish demand from the Oyan Dam, if private and public sectors were allowed to culture fish in the dam.
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    Open Access
    Nutritional and shelf-life studies of a ready-to-eat snack developed using by-products from Tilapia guineensis
    (Nigerian Society for Experimental Biology, 2021) Egbedi, B; Osibona, A.O
    Ready-to-eat (RTE) snacks were produced from the head and fins of Tilapia guineensis. The snacks were fried using the conventional method and were analyzed for their nutritional composition and shelf-life using biochemical tests (Thiobarbituric Acid (TBA), Peroxide value (PV) and Free Fatty Acid (FFA)), sensory assessment, water activity tests, and microbial analysis. There was no significant difference (p>0.05) in the nutritional composition of the two snacks developed. The snacks developed from the head without gills (PA) and the fins (PC) were low in protein (9.50±0.19 and 10.03±0.71%) and high in carbohydrate (55.33±2.02 and 51.56±2.53%). There was a significant increase (p<0.05) in the PV, TBA and FFA values throughout the storage period. Although the values for FFA exceeded the 0.5-1.5% recommended level for a noticeable rancid taste, the result of the sensory assessment of PA and PC showed that both RTE snacks were acceptable by the taste panel throughout the storage period. The range of water activity values for PA (0.57-0.78) and PC (0.59-0.64) were high and this possibly favoured the survival and outgrowth of microbial spores. The absence of Salmonella sp, S. aureus and E. coli in PA and PC, showed good manufacturing practice in terms of hygiene and food handling while the presence of low counts of Enterobacteriaceae was indicative of inadequate frying of the snack. The bacteria species identified in both products was Bacillus sp. The value for total plate count and mould count in PA was within acceptable limits until the third week of storage while its values for PC were within the acceptable limit throughout the storage period. The results show that the head and fins of T. guineensis can be used to make a nutritious snack product that would be accepted by consumers. Although the RTE snacks developed in this study offers a new snack variety and adds value to the fish by-products generated during processing, there is need to conduct more research on optimization studies which would lead to the development of protein rich RTE snacks having a longer shelf-life.
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    Open Access
    Growth Performance, Haematology and Biochemical Characteristics of CLARIAS GARIEPINUS (Burchell, 1822) Juveniles fed Quail Eggshells as replacement for Dicalcium Phosphate
    (Department of Fisheries, Faculty of Agriculture, University of Maiduguri, Nigeria, 2015) Soyinka, O. O.; Boafo, F. O.
    A ten week feeding experiment was carried out in order to examine the effect of replacing dicalcium phosphate (DCP) with milled Quail Egg Shells (QES) on the growth performance, haematology and biochemical parameters of Clarias gariepinus juveniles. A control experiment was set up with 39% crude protein diet. One hundred and fifty juveniles of Clarias gariepinus with weight range 213.0 – 215.0 g (mean weight: 213.6 ± 0.55) was fed for ten weeks on, 0, 25, 50, 75 and 100% inclusion levels of QES as a substitute for dicalcium phosphate. The results show that, highest mean weight gain (MWG) was recorded in fish fed 50% QES-based diet (44.06±7.09 g), while the lowest weight gain was recorded on the fish fed control diet (25.62±10.16 g). In the haematological parameters, the fish fed 50% egg shell had the highest packed cell volume (PCV) (38.90±0.87 g/l) and the white blood cell count (WBC) (162.60±2.71 x 109 G), while the biochemical analysis showed that the fish fed 25% eggshell diet had the best values (13.88 ± 0.62 mg/gl; 2.00 ± 2.00 mg/gel) in urea and alkaline phosphatase (ALP) respectively. It is concluded, based on the growth performance and haematological parameters that the 50% dicalcium phosphate can be replaced by milled quail egg shells in the diet of Clarias gariepinus juveniles... Although it showed a slight decrease in the biochemical parameters, it had no negative impact on the health status of the species.
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    Open Access
    Occurrence, age, growth pattern and sex ratio of Mullet species in Lagos lagoon
    (Fisheries Society of Nigeria, 2011) Soyinka, O. O.; Adekoya, O. Y.
    The occurrence, age, growth pattern and sex ratio of 334 specimens of mullets collected from the Lagos Lagoon were investigated from December 2007 – March 2008. Five species of mullets were identified and the relative abundance of species was: Liza dumerilii (35.02%), Liza falcipinnis (33.83%), Mugil cephalus (27.84%), Mugil curema (2.99%) and Liza grandisquamis (0.30%). The standard length of all mullet species ranged from 8.9 – 25.9 cm (total length range was of 11.7 – 27.6 cm) and the total body weight ranged from 11.52 – 269.84 g. The frequency polygon reflected five age groups in L. dumerilii, seven age groups in L. falcipinnis, four age groups in M. cephalus and two age groups in Mugil curema. The b- values were: 2.82 (L. dumerilii), 2.97 (L. falcipinnis), 3.60 (M. cephalus), and 4.60 (M. curema). The Liza species exhibited a negative allometric growth, while the Mugil species had positive allometric growth pattern. All the species had K-values above 1 except for L. grandisquamis. The sex ratio was in favour of the female fish in all the species examined except in M. curema. The present investigation has provided an assessment of the mullet species in the Lagos Lagoon, Nigeria, with relevant information that would be useful in the exploitation, cultivation and conservation of these under-utilised resources of this coastal community.
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    Open Access
    Growth pattern and condition factor in relation to salinity of the grey mullet from Lagos lagoon
    (Fisheries Society of Nigeria, 2011) Soyinka, O. O.
    The length-weight relationship and condition factor in relation to the salinity, of Mugil cephalus from the Lagos Lagoon were investigated for 24 months (February 2004 – January 2006). The size of the 2661 specimens ranged from 1.7 – 29.5 cm standard length (total length: 1.9 – 39.0 cm); weight (0.02 to 450.00 g) indicating the suitability of the lagoon as nursery and feeding ground. The growth pattern showed a positive allometric growth for all sexes, with a significantly high b (P < 0.05) ranged between 3.21 – 3.60 (r = 0.9003 and 0.9784). The mean condition factor (K) values ranged from 1.39 to 2.30. Salinity, the principal hydro-meteorological force operating in the lagoon ranged from 0.0 to 23.5% (mean: 9.8 + 9.13%) and the fish condition varied directly with salinity fluctuations in the lagoon, with higher condition factor in dry season than in wet season. The present utilization by the coastal communities needs to be improved upon to cater for a maximum sustainable yield of the species.