Intensive small scale cage, pen and enclosure fish production systems: towards 2010

A brief review of most of the publications by the author and other relevant workers on the three water-based fish culture systems was made. The present status of the culture systems in the National Food/Fish Programmes was highlighted. Strategies were advanced towards a successful implementation of the intensive water-based culture systems project as a contribution towards alleviating poverty, hunger and malnutrition under the concept of VISION 2010

Feeding and waste management strategies in the culture of Clarias gariepinus

Nutrient digestibility and amino acid availability were assessed in sharp-toothed catfish, Clarias gariepinus, fingerlings fed diets containing soyabean flour (SF) - Poultry meat meal (PMM) blends (25:75. 50:50, and 75:25) and 0.5 of 1.0%, Cr sub(2)0 sub(3). There was agreement between the pattern of overall protein digestibility and average amino acid availability despite the variability in individual amino acid availability the best dry matter, lipid and protein digestibility coefficients, and amino acid availability values were obtained with diets containing 0.5% Cr sub(2)0 sub(3). Chromic Oxide inclusion level appeared to affect nutrient availability. Increased marker level resulted into decreased nutrient digestibility coefficients. Similarly, these diets generated lower fecal crude protein than those with 1.0% Cr sub(2)0 sub(3). However, the latter group recorded higher protein retention efficiency. Dry mailer and lipid of diets containing more soyabean flour seemed to be more digestible than those of poultry meat meal. Similar trend was observed for the apparent availability of the amino acids. This investigation has indicated that low level of marker was better in digestibility study. Utilization of more SF than PMM in the diets of this catfish was more beneficial and should be encouraged in the feed industries producing catfish diets towards a better feed and waste management strategies in this aquaculture operation

Effect of fish meal in formulated diet on the growth of Heterotis niloticus in semi-intensive pond culture system

The aim of the investigation is to know the percentage of fish meal required to support the best growth of Heterotis niloticus in a semi intensive pond culture system. To achieve this, feed was formulated with equal percentages of blood meal, and corn meal and varying levels of fish meal. The experiment was in four treatments. Results showed that the mean weight gained was directly proportional to the quantity of fish meal made available to the fish fence 31.58g, 33.79g, 45.15g and 51.24g were recorded for treatments I, II, III and IV respectively. Result from this study when compared with previous works, shows that size of the water body to a greater extent affects the growth. The availability of fish meal in the feed made it more acceptable to the fish and hence a commensurate conversion in to flesh. The analysis of variance showed that there is significant difference in the growth performance in the treatments

Comparative growth and survival of fry of Clarias gariepinus (B), Clarias anguillaris (L), Heterobranchus bidorsalis (G), Heteroclarias, Clariabranchus and Clarias hybrids under outdoor nursery management system

Hybrids of Clariid catfishes; C. gariepinus (Netherlands), C. anguillaris, H. bidorsalis and their parental species were monitored for 8 weeks in 2 x 2 x 1m outdoor concrete tanks. The fry were fed NIFFR diet (40% crude protein) twice daily, 7 days of the week. Growth and survival records were taken weekly. The male HEB X female CLG hybrid showed an overall highest performance in growth rate while the lowest was recorded in male CLA X female CLG hybrid. The male HEB X female CLG hybrid grew at a faster rate than its reciprocal hybrid. In view or their growth rate, it is possible that the growth and survival rates or H. bidorsalis especially at the fry to fingerling stage could be improved through hybridization. The hybrid have potential as commercial food fish

Fish transplantation as an ecological tool in boosting fish production: Tiga case study

The paper discusses the status of the Tiga Reservoir Fishery pre-and Clupeid transplantation. This was achieved by examining the species diversity, abundance and distribution with mitigating factors. It concludes with a verdict on the achievement of the transplantation exercise

Alau reservoir: a multi-dimensional resource base in Borno State

Aspects of the fishery resources of Alau Reservoir in Maiduguri are reported upon in this paper. It focuses attention on the fishery in terms of fish abundance and potential. It also discusses other resources associated with the fish production. Various other possible uses of the reservoir are discussed too. The reservoir is thus revealed to be a most useful and versatile one in terms of fishery resources and fund generation

Length-weight relationship and organ indices of pond raised and wild population of C. gariepinus (Burchell 1822) pisces-Claridae

Samples of C. gariepinus collected from the wild and cultured populations in Plateau and Niger States of Nigeria were analyzed for length-weight relationship and organ indices (Gonadosomatic index (GSI), hepatosomatic index (HSI), renalsomatic index (RSI) and somatic fat deposit index (PDI). High correlation and linear relationship between body length and body weight was observed in all sample population (P<0.05). A significant difference was observed between the GSI of males and females of both wild and cultured population and also between females of the wild and cultured population,(P < 0.05).There was no significant difference in HSI, CSI RSI and PDI of all the sample populations (P < 0.05).The importance of length-weight relationship and organ indices in fish production are discussed

The effect of replacement of soyabean meal with blood meal on the growth of mudfish Clarias anguillaris (L) fingerlings

Blood meal and full fat soyabean meal were mixed in different proportions to give 0%, 10%, 25%, 50%, 75%, 90% and 100% meal in the protein fraction of the diet and fed to Claria anguillaris fingerlings in floating hapas. The growth performance of the fingerlings were monitored for 84 days. At the end of the experiment the mean weight of the fingerlings increased in the level of blood meal up to 50% blood meal in the diet after which there was a decline in the mean weight of the fish. This same level of blood meal gave the best specific growth rate, feed conversion efficiency and protein efficiency ratio. Thus the nutritive value of blood meal was enhanced by the addition of an equal level of full fat soyabean meal in the diet

Prevalence of endoparasite in some commercially important freshwater fishes of Bida area, Niger State: a preliminary report

The result of this preliminary report highlighted prevalence of an endoparasite (nematode) in order of prevalence. Four non-scaly commercially important fishes, namely:- Clarias sp Hererobranchus bidorsalis. Bagrus sp and Synodontis sp.; and nine scaly fishes, namely; - Gymnarchus sp, Protopterus annectus. Tilapia sp, Lates niloticus. Heterotis niloticus, Mormyrops sp, Channa Obscurus, Labeo sp and Distochodus rostratus of freshwater fadama of the Bida Area, Niger State. The extent of the spread was evaluated. While the reactions of fishermen, middlemen (fishmongers) and fish-eaters in order to appreciate the impacts of the nematode infested fishes on the populace were recorded. The paper suggested areas for further studies towards evoking desirable management strategies for the study area as follows. Such suggested areas are:- Identification and confirmation of the nematode species; life cycle of the nematode species; influence of season on the prevalence, spread and pathology in the nematode infested fishes, etc

Triploidy induction in Heterobranchus longifilis (Family: Clariidae) by cold shock

Triploid was induced in African Catfish (Heterobranchus longifilis) by cold shocking activated eggs at 5 degree C for forty minutes starting 3-4 minutes after fertilization. Triploidy was confirmed from mitotic chromosomes prepared from embryo which showed 100% triploidy in the cold shocking treatment and 100% diploidy in the control treatment

Environmental hazards to small scale fisheries resources management in Nigeria

This paper examined the environmental hazards limiting sustainable small-scale fisheries development in Nigeria. Observation has showed that hazards range from pollution of the aquatic habitats by domestic and urban sewage and garbage, agro-chemicals, industrial pollutants, crude oil spillage etc. In an attempt to maximize catch, many migrant and part-time fisher folks indulge in highly destructive and obnoxious fishing practices with adverse impact on fisheries resources. These have constituted significant environmental hazards. Discharges of waste from aquacultural practices in to rivers and lakes have also been identified as sources of environmental hazards. Some aquatic weeds such as water hyacinth are sources of hazards. The effects of environmental hazards on small-scale fisheries resources may be direct arising from the toxicity of pollutants or indirect as a result of ecosystem modification. Some of the effects of pollutants on the aquatic environment and fish have been discussed in the paper

The assessment of physico-chemical parameters of Shiroro Lake and its major tributaries

The physico-chemical parameters of the surface water of Shiroro Lake and its major tributaries at their entry point to the reservoir were assessed over a period of eighteen months. As in other African inland water bodies there were seasonal variations in the parameters measured. The hydrological regime of the lake, precipitation chemistry, bedrock chemistry and hydro-electric power generation influence and determine the inputs of dissolved organic carbon, nutrient levels and water quality of the lake. The added nutrients to the lake by means of the major tributary rivers and inundation of surrounding areas also influence the water quality of the lake. The wet season mean values for water and air temperature were significantly (P <0.05) higher than dry season mean values in all stations. However, for pH, Dissolved oxygen and Phosphate-phosphorus the dry season mean values were higher than wet season mean values

Growth performance of exotic Oreochromis niloticus, exotic Oreochromis niloticus fed with pelleted feeds in flow-through system

Local, exotic and hybrid tilapia fingerlings were fed 45% crude protein diet containing 18% fish meal in a flow through system in triplicate and their growth and food utilization observed for 14 weeks. At the end of the study, the hybrid (Exotic Oreochromis niloticus male x Exotic Oreochromis aureus female) fingerlings had higher growth rate and food conversion ratio (FCR) than the other treatments. This was followed by Exotic Oreochromis niloticus fingerlings. The exotic Oreochromis niloticus fingerlings came next while the local Oreochromis niloticus fingerlings were the least in growth performance. The survival rate of the local O. niloticus was however higher than the other treatments

Embryogenesis of Heterobranchus longifilis (Curvier and Valenciennes, 1840)

Studies on development of H. longifilis (Curvier and Valenciennes, 1840) were conducted at a temperature of 25EC ( 1Ec) in aquaria tanks continuous development were monitored with the use of wild Heerbrugy photomacroscope and length of yolk and larva were monitored using Stereo Olympus microscope with ocular micrometer. The division into animal and vegetal poles was observed 22 minutes after activation. The first cleavage occurred 65 minutes after activation while the second division which was perpendicular to the first line of division occurred 74 minutes after activation. This was quickly followed by the third and fourth cleavage at 80th and 82nd minutes after activation respectively. Morular stage was reached at 4 hours 20 minutes with formation of optic bud at 14 hours 35 minutes. (DBO) Developing embryo hatched after 27 hours of activation at a mean length of 6.63 and mean yolk length of 2.17. Yolk size decrease at an average rate of 38.5 % till the 5th day of total absorption. Growth of larvae proceeded faster in tail-anus region than in anus-snout portion of the body. The rate of yolk absorption and larva development (survival) as monitored in this work gives important information in Research and development programme for H. longifilis larva - an important aspect of Research development and implementation of appropriate technologies in small scale fisheries

Some ecological roles of Hippopotamus (Hippopotamus amphibious Linn. 1758) in fish production: possibilities for integrated fish-cum Agric production system

The common hippopotamus (Hippopotamus amphibious Linn. 1758) contributes to the productivity of aquatic systems where it lives. This paper reviews ecological roles of the hippo in this regard. Desk review of available literature information complemented with field observations were employed in the data collection. The ecological roles of the common hippopotamus being presented draw examples from East, West, Central and South African sub regions. The nutritional importance of the amphibious hippopotamus to rural communities was highlighted. In Southern Ethiopia, the Bodi, Bacha and Mura tribes eat hippo meat and this has led to severe hunting consequences on the wild populations of the animal. The important relationships between the hippopotamus and fish were presented. Hippopotamuses usually defecate in water and their excrements enrich the nutrients in the water resulting in favourable conditions for large fish populations. Some fish, including Labeo spp. were observed to feed on the micro-organisms and algae that grow on the skin of the hippotamus. A strong case was made for hippo-cum-fish integrated farm development in Nigeria based on ecological relationships so observed between the amphibious mammals and fish. This is one of the meeting points of fisheries and wildlife management that should be exploited for the benefits of the teeming Nigerian population