Comparative study on the catch efficiency and size selection of entangling nets in Lake Kainji, Nigeria

The relative catch performance and selectively of gillnets and trammel nets were investigated in 12 sampling stations in Lake Kainji, Nigeria. 3 types of nets with dimensions 50mx3m were constructed using 76mm and 178mm meshsizes for two gillnets, 76mm and 178mm meshsizes for the lint and ar mour nets of the trammelnets respectively. All the nets were randomly ganged together to form a fleet of nine nets each, and were set twice in each of the 12 stations which gave a total of 24 fishing operations. A total of 365 fish weighing 88.9kg and belonging to 16 different species were caught in all the nets. The trammelnet had the highest catch by number and weight constituting 60% and 69.22% of the total catch and weight respectively with a relative species Diversity Index of 0.82. This was followed by 76mm gillnet which constituted 38.63% by number, 28.09% by weight, 0.69 relative Species Diversity Index. The 178mm gillnet had the least catch of 1.37% and 2.9% by number and weight respectively with 0.25 relative Species Diversity Index. There was significant difference (P<0.05) in the number and weight of fish caught in the different nets. The minimum selection length for these species caught were the same for each net. The trammel net had a wider selection range that skewed to the right, a higher modal and median length indicating larger individual species being entangled in the ne

‘Gatekeepers’ or ‘Gatecrashers’? Rethinking the Roles of International Institutions in Global Politics

International politics as who gets what, when and how is now at its peak. Emerging powers are competing for a greater share of the world’s natural resources, while developed countries attempt to retain and wield greater influence in the international system. How these complexities interplay in the international system highlights conflicts of interests and many contradictions among states. These contradictions manifest at international institutions (especially the United Nations, UN, World Trade Organisation, WTO, World Bank and the International Monetary Fund) arenas whose creations were a product of compromise among conflicting parties. Consequently, through these international organisations (IOs) states’ interests converge or diverge. IOs have been instrumental to the consolidation of the liberal developed states supremacy in an era described as the ‘end of history’ and perceived as platforms where structural weaknesses of weak states are exposed even though weak states still attempt to push for recognition of their agenda in a world mired in a ‘clash of civilizations’. Against this background, this article interrogates how IOs consolidate and compromise as well as define the roles, power, and limitations of sovereign states for influence or mere symbolism in international politics. For instance, the paper raises questions about why the proposed on the interests surrounding the proposed reforms of the United Nations Security Council in 2005 failed due to the interests surrounding it by some states. In addition, in 1996, the WTO panel, in a case between USA and Nicaragua, determined against the US and in favour of Nicaragua, the US blatantly refused to comply and the WTO did not challenge it. Thus, the article tries to analyse the structural imbalances in the power and influence of states in international politics through IOs. How well do international institutions legitimise powerful state’s sovereignty (gatekeepers roles) and delegitimise weak states’ sovereignty (gatecrashers roles)? The paper therefore concludes that what obtains now is international politics. For it to be global, consensus building, interest free dialogue, and not impositions as the case is at the moment, is crucial and essential for the reconciliation of the differences between and among states on the floor of many international institutions; a task which is still far to seek. International institutions are becoming more important in maintaining world order[1] [1] See Robert O. Keohane, “International Institutions: Can Interdependence Work?” Foreign Policy Issue 110, 1998

Protein and amino acid requirements of warm-water fishes: a tool to efficient and low-cost fish feed production in Nigeria

Numerous investigations have utilized various semi-purified and purified diets to estimate the protein and amino acid requirements of several temperate fishes. The vast literature on the protein and amino acid requirements of fishes has continued to omit that of the tropical warm water species. The net effect is that fish feed formulation in Nigeria have relied on the requirement for temperate species. This paper attempts to review the state of knowledge on the protein amino acid requirements of fishes with emphasis on the warm water species, the methods of protein and amino acid requirement determinations and the influence of various factors on nutritional requirement studies. Finally evidence are presented with specific examples on how requirements of warm water fishes are different from the temperate species and used this to justify why fish feed formulation in Nigeria are far from being efficien

Study on the effect of two construction materials on the efficiency of fisheries aggregating devices (FADs) in Lake Kainji Nigeria

Fish Aggregating Devices (FADs) were experimented in Lake Kainji using worn out automobile lyres and cement blocks for a period of 12 weeks. Six tyres and blocks were tied together separately in 3 replicates and randomly suspended in the lake at a depth of 2 metre and 50 meter interval. After 8 weeks of suspension, a fleet of gillnets with 76mm mesh size and hung at E-value 0.5 were zigzag set across the suspended FADs for 12 fishing periods with 13 hrs soak time (~c1.0268.D.) per period The trial showed that the cement block FADs attracted more fish (70% of the total fish caught) belonging to 6 different species. The lyres FADs attracted only 3 species of fish constituting some 30% of the total fish caught Citharinus citharus dominated the catch of the block FADs constituting 52.3% of the total catch, while Oreochromis niloticus was 46.4% of the tyre FADs. The Horizontal Enhanced Fishing Zone (EFZ) was found to be between 5 to 12 metres from the location of the FADs. There was significant different (P<0.05) in the catches of the two FADs

Modelling urban growth from medium resolution Landsat imageries of Akure, Nigeria

The city of Akure has experienced rapid growth in the past 2 to 3 decades which has led to the expansion of the core urban areas of the city into adjoining rural lands. The paper analyses the urban growth of Akure using medium resolution Landsat imageries. Landsat (MSS), Landsat Thematic Mapping(TM) and Landsat Enhanced Thematic Mapper (ETM+) images for 1972, 1986 and 2002 respectively were used in a post-classification comparison analysis to map the spatial dynamic of land cover changes and identify the urbanization process in Akure. The land cover statistical results revealed a rapid growth in the built-up area of Akure from 997.2 hectares in 1972 to about 3852.70 hectares in 2002 due to increase in population of Akure within this period. Results of the prediction showed that the built-up area of the city has increased in size from 977.2 hectares in 1972 to 5863.66 hectares in 2022 corresponding to 500% at the rate of 13.1% per annum. Implications of growth include loss of open space, pressure on limited infrastructure, overcrowding, traffic congestion and poor standard of living. The study recommends regular monitoring of urban area, development of small towns around the city area to avoid overcrowding, training of planners and administrators to acquire more knowledge in the use of GIS and remote sensing to enhance efficiency

Development of a model rotatory fish smoking kiln using agro-wastes as source of fuel

A model fish smoking kiln was designed and fabricated to use agro-wastes (sawdust, palm kernel shell and rice bran) as alternative to conventionally used charcoal (control) as fuel energy source for smoking fish. Clarias gariepinus was washed, brined and smoked in chunks or whole in the kiln. The smoking kiln has an estimated capacity of 40kg of fish/batch with six fish trays and 36 fish hooks. Heat transfer is by conduction and convection. The rotatory wheel and axle on which the fish drying trays were anchored ensured even distribution of heat. The kiln has 69.4% energy efficiency and drying period of 10 hours at an average temperature range of 60 - 120degreesC, depending on the type of agro-waste used as source of fuel energy. The fuel conversion ratio, drying rates and calorific values of the different agro-waste products were also determined. Calorific value of the four agro-wastes ranged between 16.2MJ/Kg in palm kernel to 30MJ/Kg in charcoal. The drying rates of sawdust and rice bran compare favourably with charcoal and they produced smoked fish similar in dryness and quality with fish smoked with charcoal. Palm kernel had the least drying rate of smoked fish (weight/hour) during the 10-hour smoking duration

Clinical changes observed in Clarias gariepinus (Burchell 1822) fed varying levels of ascorbic acid supplemented diets

This study was undertaken to observe the clinical changes associated with the dietary ascorbic acid supplementation in the diet of African catfish, Clarias gariepinus, using the presence or absence of scorbutic (ascorbic acid deficiency) symptoms as indices. Clarias gariepinus fingerlings (6.02~c 04g) were randomly distributed into glass tanks of 60 x 45 x 45cm3 dimension at ten fish per tank in a triplicate treatment. Five diets containing 40% crude protein was formulated. Ascorbic acid (AA) was supplemented in the diets as ascorbyl-2-polyphosphate (a mixture of phosphate esters of ascorbate). Each treatment had varying levels of ascorbic acid (AA) supplementation, at 0 (Control) 50, 100, 150 and 200mg AA/kg, in Treatments 1, 2, 3, 4 and 5 respectively. Fish were fed practical diets twice daily at 900hrs and 1600hrs. Weekly weighing of fish was done and data collected were subjected to statistical analysis. At the end of week 4, fish fed scorbutic diets (diets without Ascorbic acid) had significantly lower weight than fish fed AA supplemented diets (P<0.05). After week 6, fish fed scorbutic diet began to develop clinical symptoms including lordosis (lateral curvature), broken skull, pigmentation and scoliosis (vertical curvature). Radiographs confirmed defects in the vertebral columns of fish in this treatment. Highest mortality was recorded in this treatment as 30%, In all parameters considered, treatment 4 fed 150mg AA/kg gave the best AA supplementation that prevented growth reduction and clinical signs of AA deficiency