• A brief examination of the food and biometric features of the grey mullet, Mugil cephalus (Linnaeus) from low brackish / fresh water lagoon

      Soyinka, O.O.; Okonkwo, I.C. (Fisheries Society of NigeriaLagos (Nigeria), 2010)
      A total number of 166 specimens of Mugil cephalus caught from Epe Lagoon (low brackish/ freshwater) were examined for food and feeding habit and biometric features from November 2006 ? May 2007. The food of the species consisted mainly of algae (Bacillariophyta, Cyanophyta, Chlorophyta and Pyrrophyta) and detritus. The size range of fish examined were 12.4 ? 27.0cm (standard length) while the weight ranged from 22.40 ? 308.00g. The mean values of the biometric characters of Mugil cephalus did not reflect wide variations. The population dominant cohort in the lagoon represents the harvestable and marketable representative for a sustainable fishery and is a strong indication of potential for freshwater culture of this marine species.
    • A comparative analysis of the food and feeding habits of African lungfish (Protopterus annectens, Owen) in River Rima and Goronyo Dam North Western Nigeria

      Malam, Z.G.; Ipinjolu, J.K.; Magawata, I.; Hassan, W.A. (FISONLagos, Nigeria, 2008)
      The food and feeding habits of Protopterus annectens of the River Rima and Goronyo Dam in North Western Nigeria was studied. A total of one hundred and eighteen (118) fish samples were collected from October, 2001 to September, 2002 and the stomach contents were analyzed using frequency of occurrence method. The feeding adaptation with respect to mouth and related structures, gill rakers and dentition were examined. The gut length and fish length indicated rectilinear positive relationship. The regression coefficient (b) and correlation coefficient (r) of GL TL relationships were highly significant (p<0. 01). The main taxa of food substances found in the stomachs included substances of plant and animal origins, with overall frequency of 49. 1and 38.3% for the samples from River Rima and 27.2 and 60.3% for those from Goronyo Dam in the same order. The results of percentage occurrence of the food items in the dry season showed that animal substances in the juveniles (51.7%) and the adults (41.4%) were higher than the plant materials in the samples from the two water bodies. In the rainy season, the percentage occurrences of animal substances were higher in the adults (= 30cm) samples from Goronyo Dam than those samples from River Rima, while the same food items were absent in the juveniles (= 30cm) from the two water bodies. These feeding adaptive features indicate the roles of the species in their ecological niche and provide base line information that could be useful in satisfying their food requirement under culture condition. The diversity of food substances found in the stomach and their occurrence in the juveniles and adults varied with the water bodies and season.
    • A comparative assessment of the methods of control of water hyacinth infestation with regards to fish production

      Adekoya, B.B.; Ugwuzor, G.N.; Olurin, K.B.; Sodeinde, O.A.; Ekpo, O.A. (1993)
      Water hyacinth (Eichhornia crassipes) has been subject of three control methods since its arrival into the Nigerian freshwater lagoon system in 1984 - mechanical, chemical and biological. An assessment of these three methods seems to suggest that mechanical and chemical control methods, both of which being costly, must be applied either solely or integrated to combat the present level of considerable infestation in Nigeria. The biological control methods are advisable for slow, sustained control and can only cope with low levels of infestation. It is thus concluded that the preliminary control method should be mechanical or chemical to effectively abate the nuisance plant, followed by biological control once infestation levels have been sufficiently reduced
    • A comparative study of the decomposition of Rhizophora racemosa and Nypa fruticans of the great Kwa River, Cross River State, Nigeria

      Ama-Abasi, D.; Umorem, I. (FISONLagos (Nigeria), 2013)
      Mangroves are specialized marine ecosystem which is highly productive. They act as shelter, breeding and nursery grounds for a variety of Marine and brackishwater invertebrates and fishes. Some of the dominant plant species in mangrove vegetation of Nigerian coastline are Rhizophora species and Nypa fruticans. Studies were conducted on the decomposition of Rhizophora species and N. fruticans. The objective was to compare their decomposition rates and proffer informed management decisions. Decomposition rates of the two were monitored for 112 days using litter box experiment. Eight litter boxes were stocked with 10g of leaves of each species and two boxes containing the respective plants species were removed and examined for dry matter, carbon and nitrogen contents. There was no significant difference in the rates of decomposition of Rhizophora and N. fruticans leaves (p~.0.05) even though N. fruticans showed slightly higher rate of decomposition than Rhizophora. The linear relationship between the loss in dry matter and number were expressed as Y= 10.1-0.080x in N.fruticans, and Y=9.0-0.073x in Rhizophora sp. It was concluded that the argument in favour of the eradication of N.fruticans for the thriving of Rhizophora is inaccurate. Containment of the population rather than control is the logical strategy for the management of the riparian vegetation in the face of climate change.
    • A design for commercial production of catfish (Clarias lazera) in multiple cages

      Emehelu, C.C.; Mgbemena, M.O. (1987)
      The findings are given of a preliminary study on the appropriate economical feeding rate which would enhance the growth of catfish (Clarias lazera) in cages in Lyi-ojoo Lake, Nike, Nigeria, providing also the details of the design of a practical floating platform that can be used for the culture of fish in multiple cages
    • A preliminary investigation into the effect of different storage methods on the keeping quality of smoked Oreochromis niloticus

      Oyero, J.O.; Eyo, A.A. (1999)
      The study was carried out to asses the nutritional qualities of smoked O. niloticus and to discover the best methods of storage to minimize spoilage and infestation of smoked fish. Result showed that the protein contents in A and D decreased while the protein contents of b and C increased. The lipid content increased only in A while it decreased in B-C and D. The moisture content generally increased over the period of storage and there was an increase in ash content only in C while it decreased in A, B and D. The samples packed in polythene bag suffered about 35% mould infection and a few were attached by rodents with some fouling. Samples packed in jute bag were in good condition but were slightly attached by insect. All samples packed in carton and basket were still in good state but there were insect attack in those packed in carton
    • A preliminary investigation into the effects of a sex-reversal androgen, methyltestosterone, on food utilization and growth of Sarotherodon niloticus (L) fry

      Ufodike, E.B.C.; Madu, C.T. (1986)
      Three groups of Sarotherodon niloticus fry were fed for 8 weeks on diets either treated with 17- & methyltestosterone (MT), alcohol (CA), or untreated (CO). Growth rate and food utilization in the different groups were compared. Results indicate that the best growth, Feed Conversion Ratio (FCR), Protein Efficiency Ratio (PER) and Mean Growth Rate (MGR) were obtained with the MT diet. There was no significant difference (P 0.05) in growth and food utilization of the CA and CO fry, nor in the mortality rate of the 3 treatments. The androgen, methyltestosterone promotes growth and protein anabolism without producing toxic effects in S. niloticus
    • A preliminary investigation into the post harvest losses of fish in Shiroro Lake area

      Oyero, J.O. (2001)
      The findings are presented of a study conducted to assess the post harvest losses in Shiroro Lake, Nigeria. The major objectives were to identify and quantify the types of losses, to provide recommendations that would enhance formulation of policy guidelines for utilization and exploitation of the declining fishery resources of the lake
    • A preliminary survey of the helminth fish parasites in Imo River

      Ugwuzor, G.N. (1985)
      A preliminary survey of the helminth fish parasites was carried out in Imo River (Nigeria). A total of 191 fishes belonging to 15 genera were examined and only 13.6% were infested with various species of helminth parasites which is low percentage of infection. The following helminth parasites were recorded. Wenyonia virilis, kainji; Wenyonia sp., Procamallanus laeviconchus; Procamallanus sp., Sprionoura congolense; Spironoura sp., Cucullanus sp. and Serradacnitis serrata. It was found that helminth parasites showed some degree of specificity in their distribution within their fish hosts. This specificity could be as a result of the physiochemical and physiological factors operating in the gut such as pH, osmotic tension, oxygen tension and nutrient levels. The results also revealed that age and sex influence helminth parasites infections in fishes
    • A prelimnary study of diet in the juvenile gorean snapper, Lutjanus goreensis (Valenciennes, 1830) from Five Cowrie Creek, Lagos, Nigeria

      Fakoya, K.A.; Abass, M.A.; Owodeinde, F.G.; Lawson, E.O.; Ojo, F.R. (Fisheries Society of NigeriaLagos (Nigeria), 2010)
      Diet of the juvenile Gorean snapper, Lutjanus goreensis from Five Cowrie Creek was investigated between April 2008 and January 2009. Analyses of 184 specimens by numerical (NO), frequency of occurrence (FO) and geometric index of importance (GII) methods, respectively revealed a moderately high proportion (47.83%) of stomachs with food or prey. Shrimps and crabs constituted more than 80 % of total prey items. Other dietary components included lobsters, stomatopods, whole fish and fish parts. Similarly, analysis of diet composition by size - groups also indicated a predominance of the shrimps and crabs over all other prey items. In conclusion, L. goreensis can be described as a top-level carnivore feeding almost exclusively on epibenthic crustaceans in the juvenile stage.
    • A proposed integrated livestock-rice-poultry-cum-fish culture in enclosure system

      Otubusin, S.O. (1987)
      Integrated agriculture-cum-fish farming has been practised profitably for ages in the Chinese small-scale farming system. There is a great potential for this system by utilizing the vast Nigerian flood plains (approx. 515,000 ha). Dogongari Bay in Lake Kainji Basin was identified as a suitable site for this system after some extensive fish culture trials. Polyculture of Clarias spp., Heterotis niloticus and Tilapia was proposed for integration with layers in the poultry house, 2-ha upland rain-fed rice farming and indirect cattle rearing in the 5-ha enclosure site. Cost benefit analysis showed that the system will consistently record profit as from the second year of operation. Various complex factors were identified to affect profitability of this mixed farming system. Concerted research approach is needed to fully understand the interrelationships of the various components of this integrated system. Generous funding of research activities is very crucial in this situation
    • A quantitative analysis of demand for fish in Nigeria

      Fatunia, G.T.; Oladimu, O.L.; Ladipo, O.O. (1983)
      The paper discusses the relevant theoretical considerations and specifies a model in an attempt to quantify those variables, the changes of which affect the internal demand for fish in Nigeria. Regression analyses carried out show that a generally rising trend in per capita income will increase the demand for fish, other things being equal. It is further revealed that even as the price of fish goes on increasing, consumers' demand for fish also tend to rise. The paper concludes by emphasizing the need for a fish consumption survey in the country's fish demand
    • A review of bonga fisheries of the Cross River State, Nigeria

      Usentip, N.U. (1985)
      The Nigerian pelagic fishery contributes about two-thirds of the total marine fishery resources of the country. The main components of this fishery are the clupeid (Ethmalosa, and Sardinella spp) and the scombroid (jacks, barracuda and tuna) fisheries. In 1979 to 1983, fish production from the national inshore and brackishwater zones was 1,702,685 tonnes. Bonga (Ethmalosa fimbriata) which dominates the pelagic fishery in the Cross River State of Nigeria, contributed about 158,612 tonnes (i.e. 9.3%) of this national marine fish catch. Although bonga is caught along the entire Nigerian coast, a significant fishery exists mostly in the wider estuary of the Cross River State, which borders on the Cameroon Republic. In the Cross River State, and within the period, bonga contributed 24% to the marine fish landings. Bonga is supported by a single species (E. fimbriata). The species forms an important fishery all the year-round in the open sea off these estuaries, whenever the canoes venture to sea, but these open sea fisheries are affected by whether conditions. The best, and most suitable gear for bonga are the gill nets, cast nets, boat seines, and shore seines. Dried and smoked bonga are a common market commodity in the southern parts of the country generally, but particularly in the Cross State where it is a readily available and acceptable food item
    • A review of diseases associated with cage culture systems: diagnosis and control in smale scale fish farming

      Okaeme, A.N.; Olufemi, B.; Amubode, F. (1999)
      Fish cage culture is a rapid aquacultural practice of producing fish with more yield compared to traditional pond culture. Several species cultured by this method include Cyprinus carpio, Orechromis niloticus, Sarotherodon galilaeus, Tilapia zilli, Clarias lazera, C. gariepinus, Heterobranchus bidorsalis, Citharinus citharus, Distochodus rostratus and Alestes dentes. However, the culture of fish in cages has some problems that are due to mechanical defects of the cage or diseases due to infection. The mechanical problems which may lead to clogged net, toxicity and easy access by predators depend on defects associated with various types of nets which include fold sieve cloth net, wire net, polypropylene net, nylon, galvanized and welded net. The diseases problems are of two types namely introduced diseases due to parasites. The introduced parasites include Crustaseans, Ergasilus sp. Argulus africana, and Lamprolegna sp, Helminth, Diplostomulum tregnna: Protozoan, Trichodina sp, Myxosoma sp, Myxobolus sp. the second disease problems are inherent diseases aggravated by the very rich nutrient environment in cages for rapid bacterial, saprophytic fungi, and phytoplanktonic bloom resulting in clogging of net, stagnation of water and low biological oxygen demand (BOD). The consequence is fish kill, prevalence of gill rot and dropsy conditions. Recommendations on routine cage hygiene, diagnosis and control procedures to reduce fish mortality are highlighted
    • A review of essential checklists for fish cage culture

      Mafolabomi, M.W.; Adeparusi, E.O.; Balogun, A.M. (FISONAkure (Nigeria), 2009)
      Nigeria has potentials for high production of fish from her water bodies. Fishing is the predominant means of fish supply that needs to be increased by fish fanning in different enclosures. Cage aquaculture is possible in several existing water bodies. The essential inputs for a successful fish cage farming therefore need to be considered. This would be an added wealth creation for job seekers/farmers hitherto involved in traditional fishing.
    • A review of length-weight relationship and its parameters in aquatic species

      Ama-Abasi, D. (FISONLagos, Nigeria, 2008)
      Length weight relationship and its parameters are requiring in practical assessment of stocks of aquatic species. The exponent b describes the growth condition of the species in question. If the value of b is 3 around 3, the fish is said to exhibit isometric growth if the value of b is less or greater than 3 the species is said to exhibit isometric growth if the value of b is less or greater than 3 the species as exhibiting both isometric and allometric conditions. Such conclusions are erroneous and misrepresentation of scientific facts. They stem from the use of inappropriate methods in estimation of the LW parameters and the authors? lack of understanding of the biological theory behind the growth conditions. To correct these erroneous presentations, the paper highlights the appropriate approach for the estimation of the LWR parameter. Large sample size. Wide size range and appropriate statistical tools are essential ingredients for accurate estimation of the LW parameters. The paper also elucidates on the concept of isometric and allometric growth in fishes and other invertebrates. A minimum of one year time scale of data collection in order to capture all the size ranges, from the young of the year to the oldest individual in the population, so as to reflect the ontogenetic growth performance of the aquatic species, have been proposed
    • A review of manpower training for Nigeria's fishing industry

      Olaniawo, A.A. (1983)
      An examination is made of the organization and administration of fisheries training institutes in Nigeria, highlighting their inadequacies in achieving required goals. A systems approach to fisheries manpower training is described which is based on 4 principles: 1) wholeness; 2) systematization; 3) compatibility; and 4) optimization
    • A review of recent advances in commercial tilapia culture

      Sagua, V.O. (1987)
      The paper introduces the tilapias as important culture fish; their classification, breeding habits and general ecology are discussed. The versatility and plasticity of their reproduction and growth are major advantages as well as draw backs in their use as culture species. The culture of tilapias in ponds, cages, pens and raceways are described and a comparison of extensive and intensive cultivation is made. The major factors in commercial cultivation of tilapias such as feeds, hatchery/fry production and disease control are discussed. Recommendation is made for the consideration of tilapia as the equivalent of the common carp in tropical African fish culture in either monoculture or in polyculture with other fish species