Recent Submissions

  • Prospects of fish smoking venture in the middle belt area of Nigeria.

    Akande, G.R.; Tobor, J.G. (Nigerian Institute of Oceanography and Marine ResearchLagos, Nigeria, 1993)
    This paper discusses fish smoking in general with particular reference to the Middle Belt Area and also briefly summarises the fisheries of the area. Factors influencing the form in which fish is disposed are discussed and investment opportunities of fish smoking on a small scale examined.
  • Microbiological studies of the mangrove oyster Crassostrea gasar (Adanson 1757) from an experimental fish farm of the Lagos lagoon, Nigeria.

    Ukwade, I. M. (1990)
    Crassostrea gasar, the mangrove oyster and the surrounding fish farm water were examined microbiologically. The aim was to determine the bacterial load and level of contamination. Oysters were collected from the experimental fish farm of the Nigerian Institute for Oceanography and marine Research, with its water source from the Lagos Lagoon. The oysters were discovered to be contaminated, with the Coliform/Eschericia coli counts in the range of 56/100g to above 1,800/100g for samples collected. Salmonellla pathogen was present and the counts were in the range of 3.10 x 102 to 1.99 x 106 per gram. The total viable becteria counts were in the range of 3.18 x 102 to 2.20 x 106 per gram. Analysis of the farm water revealed a positive correlation in microbial counts of the oysters and the surrounding water.
  • Growth response of clarias gariepinus (Burchell 1822) on silage-based diets.

    Ayinla, O.A.; Akande, G.R. (1988)
    The feeding trial of C. gariepinus using three silage based diets and one fish meal based diet was carried out in concrete tanks. The four experimental diets were fed to C. gariepinus fry of relatively the same size. At the end of 8 weeks feeding trial the fish increased from their initial body weight of 0.2g, 0.4g, 0.4g and 0.4g to average final weights of 21.2g 15.4g, 12.8g and 13.8g respectively. The diet containing 41.1% resulted in the least food conversion efficiency of 1.2 over the eight weeks period. Of the experimental treatments the diets containing the highest level of fish silage (41.0%) performed better than any of the other two treatments of 19.0% and 33.5% fish silage contents. Apart from the nutritional superiority of 14% fish meal-based diet over the 41% fish silage-based diet the commercial production of fish silage is not yet feasible in Nigeria hence the need to look for the alternative protein source for the replacement of the expensive fish meal in the diet of culturable fish.
  • Sodium alginate as a binder in fish feeds and its effects on the nutritive quality of tilapia diets.

    Igbinosun, J.E.; Roberts, O.O. (1988)
    Pelleted feeds A.B, C and D containing 4% 3%, 2% and 1% sodium alginate respectively were tested for water stability in terms of floatation time, sinking rates and crumbing rates (on getting to the bottom of the tank). Results showed that although all the pellets had Zero Floatation time, it took pellets from the D group longer time to sink. A and B pellets sank at equal rates. The crumbling rates on getting to the bottom tended to decrease with decreasing levels of binder. When the diets were later fed to four groups of Tilapia fingerlings for seven weeks, results showed that the growth rate, feed conversion efficiencies and protein efficiency rations followed the trend C> D> B> A. It is therefore suggested that 2% level of alginate binder is quite optimum in fish feeds especially for Tilapia.
  • Preliminary studies on the initial weathering of oil on water.

    Oyewo, E.O. (1988)
    Laboratory-scale studies on the initial weathering of some oils on water by evaporative loss and dissolution have been carried out. Evaporation rate was dependent on the type of oil and was accelerated by increased temperature, number retarded evaporation rate. The order of evaporation rate was Gas Oil >Diesel Oil > Medium fuel Oil. Dissolution rate, which varied with the type of oil, was retarded by salinity but promoted by increased temperature. With the mono-component oils tested, the cyclic, aromatic and iso-characters increased dissolution rate. The order of dissolution rate for the commercial oils was Gas Oil  Diesel Oil > Medium Fuel Oil.
  • Possible upwelling phenomenon off the Nigerian coast

    Ibe, A.C.; Ajayi, T.O. (1985)
    Published information favour the occurrence in certain years of wind related upwelling in Nigeria's inshore waters especially between July and September. This is corroborated by the prevalence of petroleum source beds, glauconite, phosphorite and periodic abundance of some fish including Engraulis encrassicolus, Sardinella maderensis and the bonga Ethalmosa fimbriata which are pelagic and are associated with upwelling phenomena. Examination of temperature and salinity data for 1978 - 81 suggested that upwelling occurred during certain periods of each year. However, wind data for the same period lacked details to support postulates of wind driven upwelling. Instead, dynamic upwelling resulting from the juxtaposition of the currents in the area is adduced. This was probably augmented by transitory wind driven upwelling. A minor upwelling between December and February proposed by previous workers, though not apparent from this study, could emanate from channeled flow of off-shore winds.
  • The reproductive biology and culture of macrobrachium vollenhovenii (Herklots, 1857) and macrobrachium macrobrachion (Herklots, 1851) in Nigeria.

    Marioghae, I.E.; Ayinla, O.A. (1995)
    Macrobrachium vollenhovenii and Macrobrachion, the two largest Macrobrachium species in Nigeria waters attain maximum adult sizes of 19cm and 13.5cm respectively. Male - female ration is approximately 1.1 for both species. Male dimorphism has been observed in M. macrobrachion but not in M. vollenhovenii. Both prawns breed throughout the year (usually in the brackish waters) with peaks in the rainy season. Although berried females of M. vollenhovenii occur in landlocked water bodies, rearing the larvae has so far been successful in brackish water. Bi-weekly spawning peaks occur in M. macrobrachion but are still to be verified for M. vollenhovenii. Induced spawning has been successful carried out for M. vollenhovenii by using a combination of pituitary hormone and changes in illumination, temperature and water level. Clutch size ranges from 1,000 - 10,000 for M. macrobrachion and 45,00 - 400,000 for M. vollenhovenii. Egg incubation takes 16-20 days in both species. Two culture trials using diets of 14% crude protein and agriculture by-products of unspecified composition, gave growth rates of 0.24g/day and 0.03g/day respectively.
  • On technical viability of the trawler fishery in Nigeria

    Amadi, A.A.; Tobor, J.G. (1988)
    The concept of technical viability is defined as a combination of factors including fishery resource. Ecology, gear technology, manpower and entrepreneurial skills financial inputs and product markets. A clear drop in catch per trawler per year in Nigeria is attributed mainly to inadequate cash flow to operate vessels in the face of high fuel costs, lack of spare parts and repair facilities, and some growth over fishing of ground fish stocks. The transition from artisanal to rapid industrial mechanized fishing has not been matched by the availability of skilled local manpower to effectively operates and service electronic, hydraulic and refrigeration equipment of modern trawlers. While Nigerian financial institutions have to some extent financed trawler purchases, negligible assistance is directed at acquisition of post- harvest facilities, processing, construction of fishing terminals and cold stores. This neglect contributes immensely to losses incurred from spoilage of catch. Some suggested remedies are packaged in the form of discussions on effective mechanisms to conserve stocks, training proposals, fuel saving devices in trawlers and the role of the state in ensuring suitable conditions for fisheries development.
  • Variation in the physico-chemical features and phytoplankton of new Calabar river at Aluu, Rivers State, Nigeria.

    Erondu, E.S.; Chindah, A.C. (1991)
    The physico-chemical features and phytoplankton community of the upper reaches of the New Calabar river at Aluu were studied at high and low water slacks for a period of 12 months. The water was acidic (pH 5.5 – 6.5) with low alkalinity (10 – 20mg CaCO3 L-1 and characteristically soft (total hardness ranging from 10 to 60mg CaCO3L-1). There was obvious seasonal flux in the silica level, with dry season having higher values than wet season. The phytoplankton was predominated by the diatoms, which constituted more than 85% of the total phytoplankton population. The predominant taxa were Melosira sp. Tabellaria spp. Surirella spp. and Navicula spp. The phytoplankton density was significantly higher during the dry season than rainy season (Czekanowski’s Coefficient.Cz = 0.332) but there was no significant difference between the high and low tide values (Cz = 0.66).
  • Acute toxicity tests of a textile mill wastewater effluent and a "detergent wash" with a Hermit crab (Climbinarius Africanus) (Aurivillius)

    Ajao, E.A. (1985)
    Bioassay tests were conducted with wastewater effluents from a textile mili and a detergent packing plant using the hermit crab. Clibinarius africanus. (Aurivillus) as experimental animal. LC50 values were evaluated using static testing procedures for 24, 48 and 96 hour. For the textile effluent, means of 79.0, 50.24 and 51.81 percentage effluent by volume were obtained in respect of crabs in the “medium” weight range (0.3 – 0.7grams) for the test periods. For the “detergent wash”, 95.16, 85.00 and 82.33 percentage effluent by volume represented means of values obtained for “small” size crabs (weight range 0.08–0.24 grams) and 96.0, and 81.50 percentage effluent by volume for ‘medium’ size crabs for 24, 48 and 96 hour respectively. Spearman’s Rank correlation coefficient showed no relationship between the variable weight and survival rate within the weight range used (p>0.05 for the two-wastewater effluents. For the textile mill effluent, a two-way analysis of variance showed no significant differences between aerated and unaerated test solutions within a 96 hour period. Presumable safe concentrations have been compound using 0.1–0,05 and 0.1–0.01 as arbitrary application factors for the textile mill and “detergent wash” respectively. Some cost benefit recommendations are suggested based on observed plant processing activities
  • Performance of Clarias gariepinus in a polyculture with Oreochromis niloticus.

    Oladosu, G.A.; Ayinla, O.A.; Onuoha, G.C.; Needom, J.G. (1990)
    A study of the performance of Clarias gariepinus (African Mudfish) in a polyculture with Oreochromis niloticus (Tilapia), integrated with broiler chicken production was carried at the African Regional Aquaculture Centre, Nigeria. Three experimrntal treatments were utilized. Treatment I was a polyculture of C. gariepinus and O. niloticus integrated with broiler chicken production, with application of supplemental feed to fish. Treatment II was a repeat of treatment 1, except that no supplemental feed was applied to fish, while treatment III was a polyculture of the two fish species per se with application of supplemental feed to fish. Results showed that the final individual weight, individual weight gain and recovery rate were best for C. gariepinus, under treatment I. Moreover, C. gariepinus yield in treatment II was 47.7% of that of treatment I, while yield in treatment III was 15.6% and 32.7% of those treatments i and ii respectively. Furthermore the comparisons of the daily growth rate for each of the fish species under different treatments were made. Statistical analysis showed that there is no difference (F >0.10 and F > 0.05) in the mean growth rate and average yield of both fish species, in all the treatments. A further comparison of these parameters (mean daily growth rate and average yield) showed that there was significant difference in the mean daily growth rate between treatments I and III only, and in the mean yield between treatment I and II, I and III and II and III. Furthermore, the possible effect of some physico-chemical parameters of the pond water, on the growth and survivability of the stocked fish species were discussed.
  • Stock assessment of the threadfin (Galeoides decadactylus) from the Nigerian inshore waters.

    Abohweyere, P. O. (1989)
    Galeoides decadactylis is a commercially important species of the family polynemidae and constituted 10-20% by weight of the total landing of the trawl fishery in the 60s (Longhurst 1964a). Between 1971 and 1985 landing figures of the fish showed a fall of 7 – 8% by weight of total fish landed (FDF and NIOMR. 1986). Length frequency distribution showed the average size of fish landed by the commercial fishing company was 23.03cm while that of the Institute’s Research vessel was 18.89cm. Catch curve analysis showed that the fully exploited length ranged between 17 and 31cm. The length at infinity (Lx) obtained was 47.75cm while the growth coefficient (Z) was 0.20. Estimated total mortality (z) was 0.36. The stock size estimates was 10,090.54 tonnes, while the maximum sustainable yield (MSY) was 52.03t and the potential yield value, 1.816.30t.
  • Tolerance tests with three refined petroleum products and edible mollusc - Tympanotonus fascatus (Linne)

    Oyewo, E.O. (1988)
    The tolerance of Tympanotonus fuscatus (linne) to films and dispersions of three refined petroleum products has been investigated. The tolerance ranking was Diesel Oil > Kerosene > Petrol. The dispersions were more deleterious to the test animals by varying orders of magnitude. Responsiveness and the capacity for proper orientation were adversely affected with the latter being affected before the former. An indication of upper threshold values for two of the observed responses is presented.
  • Effect of season on controlled propagation of the African catfish, clarias gariepinus (Burchell 1822).

    Ayinla, O.A.; Nwadukwe, F.O. (1990)
    The effect of season on the controlled propagation of C. gariepinus was investigated. The hypophysation of C. gariepinus using the pituitary extract from the sacrificed C. gariepinus was carried out from July, 1987 to June 1988. The female broodstock weight ranged from 0.50kg while the male weight, from 0.5kg to 0.6kg. The condition factor of the female broodfish was more or less uniform (1.3 to 1.7). The results showed that there was peak production of eggs by the female during the rainy season. Eggs production for rainy season ranged from 28,000 eggs/kg body weight in June to 37,600 eggs/kg body weight in August. The percentage hatching of the fertilized eggs was also higher in the rainy season than the dry season. The highest hatching of the fertilized eggs of 86.4% was obtained in July and the lowest of 40.1% in December at the temperature range of 23oC to 27oC respectively. The hatching of the fertilized eggs occurred between 23 to 29oC with the optimum at 27oC. The hatching of the eggs took place from 18 to 30 hours. The fry were stocked into 1000m2 grow –out ponds 4 days after hatching. The fry were reared to fingerlings in the grow-out pond for four weeks. Fingerlings percentage survival from the fry was within the range of 13.6% to 54.0%. The highest fry survival of 54.0% was obtained in September and the least of 13.6% in January. This study has shown that controlled propagation of C.gariepinus can be done year round.
  • Fish feed and nutrition in Nigeria: the present state of knowledge and the way forward.

    Ayinla, O.A.; Bekibele, D.O. (1982)
    The fish feed and nutrition in Nigeria was reviewed. Crab meal, shrimp head meal, tadpole meal, soybean meal were used for partial or total replacement of fish meal in the diets of cultivable fish species and no satisfactory result is yet obtained for 100% of replacement of fishmeal. The cost price of species specific diets so far developed is out of tune for profitable fish farming venture. Further investigation is required to develop cost effective species specific diets. The problem in feed and nutrition was highlighted and possible solutions were proffered.
  • Online beach evolution model for Nigerian shoreline: a case study of Victoria bar beach, Lagos

    Ibe, A.C.; Inegbedion, L.E.; Egberongbe, F.A.O.; Orupabo, S. (1989)
    The dynamic state of the Nigerian shoreline, dominantly erosional has been a source of concern to various state and Federal Governments particularly in the past few decades because of the enormous adverse socio-economic implementation it engenders. An ability to predict the future behavioural patterns of the Nigerian shoreline affords an invaluable scientific input into long term and large scale managerial planning for the Nigerian coastal zone. This paper documents a first attempt at formulating a mathematical model for beach states in Nigeria using Victoria bar beach as a case study. A controlled section of the beach was selected while measurements of some of the variable characteristics were carried out periodically. While it is ultimately desirable to include such variable i.e. meteologic, oceanographic information in the modelling process, such an attempt at this stage will be unnecessarily cumbersome. This paper therefore focuses on a time variant volumetric expression for the behavioural pattern of the Victoria bar beach. Results obtained show system solution of the form. R = ∫to h(t) x (t – c)dt Where R is the System output rate; h(t) is an response function, characterizing of identifying system; C is a dummy parameter of time and x represents the inflow into the control volume.
  • Production of salted cakes from the flesh of stunted tilapia spp. and silage from their offal.

    Akande, G.R. (1989)
    The yield of mince from stunted Tilapia species using a flesh-bone separator was investigated. Salt was added to the mince to prepare dried cakes with enhanced keeping qualities. Pre-heat treatment of the cakes prior to low temperature drying resulted in an initial moisture loss and improved the appearance, flavour and texture of the cakes. The dried cakes were assessed for total viable counts and sensory attributes after preparation and storage. Desalting of cakes was effected by boiling in water, Salted dried cakes were found to be microbiologically stable and the reconstituted cakes organoleptically acceptable after a storage period of 2 months. Feed compounded from Tilapia offal silage kept better than feed from fishmeal and was not mouldy after 6 months of storage.
  • Proximate composition, microbiological and sensory evaluation of canned skipjack tuna ( Katsuwonus pelamis ) stored at ambient and accelerated tempratures.

    Akande, G.R.; Emokpae, A.O.; Towuru, E.T.; Ogbonna, C.; Ajayi, A. (1988)
    The yield of skipjack tuna (Katsuwunus pelamis) was investigated. It was found that 2,75kg of fresh tuna are required for the production of every 1kg of canned tuna. Pre-cooking of tuna which is a major processing stage in tuna canning resulted in a loss of about 19% of its weight based on gutted and headed fish. Changes in the quality of canned tuna packed in brine, oil and tomato sauce at ambient and accelerated temperatures were examined by microbiological and sensory evaluation methods. Canned tuna samples were found to be microbiologically stable and organoleptically acceptable after one year storage period. Total viable counts (TVC) were generally low. Thermophilic organisms, anaerobes (clostridium) and coliforms (E. Coli type 1) were absent in all the canned samples. Comparison of the locally canned tuna with imported ones showed similar trends in terms of the proximate composition, microbiological stability and sensory evaluation.
  • The foraminiferal fauna of the Bony estuary: A baseline study.

    Dublin-Green, C.O. (1990)
    The effect of oil exploration, production and other oil related industrial activities on the estuarine environment of the Niger Delta has resulted in increasing need of baseline information to be used as background levels against which pollution effects could be detected and monitored. A one-year (December, 1986 - December, 1987) baseline survey of the benthic foraminiferal fauna of the Bonny estuary showed that arenaceous forminifera strongly dominated the total and living assemblages. The subordinate calcareous groups were mostly found in the lower reaches of the estuary. The foraminiferal fauna was represented by thirty-three species, twenty-three of which were arenaceous, nine calcareous and one porcellaneous. Twenty nine of the thirty-three species identified were found living. Population densities in the estuary varied from 6-1,604 specimen per 20cc wet sediment for total population and 2-392 specimens for living populations. Two indices of species diversity, the species number [S] and fisher  index were employed in estimating diversity trends in the benthic foraminiferal fauna. Species number [S] per 20cc wet sediment varied between 2-18, while fisher  index ranged from 0.9-4. Some environmental indicators species identified in the area of study include, Arenoparella mexicana, Ammobaculites spp, Miliammina fusca, Trochammina inflata, Haplophragmoides subinvolutum, Ammotium cassis, A. aff. Okrikum, Elphidium excavatum and Ammonia beccarii variants
  • Benthic foraminifera as pollution indicator in the Bonny estuary, Niger delta.

    Dublin-Green, C.O. (1994)
    A seasonal study of the diversity of benthic foraminifera in the Bonny estuary was carried out at ten Stations located at various zones in the estuary. Four diversity indices, species number[S], Fisher & shannon Wiener function H(S) Equitability (E) were employed in the analysis. Examination of the spatial distribution and seasonal variations of these indices provided information on the responses of the foraminiferal fauna pollution. Diversity indices, S& and H(s) were found to be consistently low at station 5 (NNPC Refinery jetty Okrika). The dominance of pollution – tolerant species such as Ammotium salsum, Miliammina fusca and Ammonia beccarii at this station was also observed. The loe diversity indices recorded at station 5 is attributed to the fact that, it is a stressed environment resulting from pollution due to refinery effluent and oil wastes from marine tankers. Some cosmopolitan environmental indicator species identified in the study area, which could be used for subsequent monitoring studies, include: Arenoparrella mexicana, Miliammina fusca, Haplophragmoides subinvolutum, Ammotium salsum, Elphidium gunteri, Ammonia beccarii parkinsoniana and Ammonia beccarii tepida.

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