A review of bonga fisheries of the Cross River State, Nigeria

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 ite

River Sediment Sampling and Environment Quality Standards: A Case Study of the Ravensbourne River

Sediment is a major sink for heavy metals in river, and poses significant risks not only to river quality but also to aquatic and benthic organisms. At present in the UK, there are no mandatory sediment quality standards. This is partly due to insufficient toxicity data but also due to problems with identification of appropriate sediment monitoring and analytical techniques. The aim of this research was to examine the sampling different river sediment compartments in order to monitor compliance with any future UK sediment environmental quality standards (EQS). The significance of sediment physical and chemical characteristics on sampling and analysis was also determined. The Ravensbourne River, a tributary of the River Thames located in the highly urbanised South Eastern area of London was used for this study. Sediment was collected from the bed using the Van Veer grab, the bank using hand trowel, and from the water column (suspended sediment) using the time integrated suspended tube sampler between the period of July 2010 and December, 2011. The result for the total metal extraction carried out using aqua regia found that there were no significant differences in the metal concentrations retained in the different compartments by the <63μm sediment fraction but there were differences between the 63μm-2mm fractions of the bed and bank. The metal concentration in the bed, bank and suspended sediment exceeded the draft UK sediment quality guidelines. Sequential extraction was also carried out to determine metal speciation in each sediment compartment using the Maiz et al. (1997) and Tessier et al. (1979) methods. The Maiz et al. (1997) found over 80% of the metals in each sediment compartment were not bioavailable, while Tessier et al. (1979) method found most of the metals to be associated with the Fe/Mn and the residual phase. The bed sediment compartment and the <2mm (<63μm + 63μm-2mm) fraction appears to be the most suitable sediment sample for sediment monitoring from this study

A review of the crayfish fishery of Nigeria with special reference to the Cross River State

The fishery for crayfish is of considerable importance in the maritime region of the Cross River State, Nigeria, where it forms an important occupation of a host of fishermen. Crayfish landings from this State contributed 11% to the national marine fish landings within the period 1980 to 1984 and also in the same period the volume of crayfish alone formed 26% of the marine fish landings within the State. The species exploited as crayfish include Palaemon hastatus; Hippolysmata hastatoides, and Macrobrachium sp; mixed with the larval, and juveniles of pink shrimp Panaeus dourarum. They are generally small in size ranging from 7 cm (maximum) to 2.5 cm. Crayfish are caught all year round along the Niger Delta, but particularly along the river estuaries and littoral waters of the Cross River State with the highest production occurring in March to May. Crayfish are usually smoked, and occasionally sun-dried, and they form an indispensable food item in the diet of the people of the entire southern States in particular and Nigeria in general. It appears that crayfish landings could be substantially increased without depleting the stock, if a proper exploratory survey is undertaken of the Niger delta, and the Cross River estuaries to chart potentially rich grounds of this resourc

Status of the demersal fishery resources of Bangladesh

The present study makes use of the fisheries survey data collected during the period 1984 - 87 by the multi-purpose research vessel RV Anusandhani in the waters of Bangladesh, Bay of Bengal. The data consists of twelve survey cruises directed at the shrimp resources (1985 - 87) and nineteen survey cruises directed at the demersal fish resources (1984 - 86). The biomasses for shrimp and demersal fish during the survey period were estimated, along with a detailed analysis of biomass distribution by depth zone and catch rates for important species of shrimp and demersal fish species. The demersal fish and shrimp biomass during the survey period was estimated as 176 160 t and 857 t, respectively. The levels of biomass when compared with 1973 estimates indicate a tremendous decline, by about 90% for shrimps and 30% for demersal fish. Population parameters for four species of shrimps (for both males and females) as well as for eight demersal fish species were also estimated. The parameter estimates were validated using available growth and mortality parameter values from the literature, and were in turn used to estimate the mean exploitation rate (E) of demersal fish and shrimp species comprising the trawl catch. Mean E values for shrimp species is at 0.61 and 0.57 for demersal fish species, indicating over-exploitation of demersal resources in the Bay of Bengal. Exploratory analysis using surplus production modeling of catch and effort data shows that the maximum sustainable yield (MSY) level for shrimp resources is around 3 500 t, corresponding to a maximum effort level of approximately 6 480 fishing days. Similar analysis for demersal fish catches gave poor correlations between catch rates and fishing effort.Fishery resources, Demersal fisherie, Fishery surveys, Biomass, Population density, Shrimp fisheries, Catch/effort, ISW, Bangladesh,

A review of the commercially exploited marine fishery resources of Nigeria

The annual estimated total marine fish catch in Nigeria for the period 1971 to 1979 is 0.3299 million metric tons. The differential distribution pattern of the predominant fish groups for the maritime states, the component species, their life habits in relation to hydrographic factors leasing to seasonal fluctuations in the fisheries are highlighted, focussing also on the types of fishing carafts and gear in common use along the coastal states and the fish species obtained from them. The landings by the exploratory and commercial fishing trawlers including the distant water vessels (imports) form about 4.24% of the total marine fish landin

Existence of optimal controls for a class of hereditary systems with lagging control

In this paper the problem of existence of optimal controls for a class of time lag systems is considered. It is schown that Oğuztöreli's results (Oğuztöreli, the 8.1, p. 184, “Time Lag Control Systems,≓ Academic Press, New York, 1966) can be extended to a class of time lag systems whose “phase velocity≓ depends also on the past history of control

Concerning miracles: An existential analysis of some critical insights from Hume and Lewis

People have questioned the veracity of miracles, especially when viewed as what is extraordinarily contrary or tremendously opposed to the normal course of natural events. Some scholars, headed by David Hume, opine that miracles are not really miracles, especially when understood as a flagrant transgression of nature. Others, spearheaded by Carl S. Lewis, posit that miracles are not only possible, but also real and factual, especially when they are considered from the perspectives of people’s experiences. However, flowing from these, this article reasons that the basis of acceptance of miracles is no scientific proof but a living faith that trusts the person, role and function of God in human life. This makes it obvious that, while there are no scientific proofs, there are firm indications that miracles are real in the life of the believing community

Effect of nutrition education on the consumption pattern of students of secondary schools in Ikot Okpora of Biase Local Government Area of Cross River State, Nigeria

This research on effect of nutrition education on the consumption pattern of secondary school students in Ikot Okpora in Biase Local Government Area of Cross River State was aimed to investigate the types of food available in Ikot Okpora.Methodology: Survey and purposive sampling was used to select three hundred and twenty students of the school since the number was small and one hundred (100) parents. Descriptive statistics, percentages and independent paired sample t-test was used to separable and compared.Result: The result of the study showed that majority of the parents were teenagers (36%) who were mostly farmers/traders (40/26%) respectively and who are majorly low income earners (N15,000,00) per month. A significant increase in some food items such as dairy products, vegetables, legumes, meat and fish product, pastas, baked products after and a reduction of consumption in food items of carbohydrates such as starchy roots a tubers, cereals, sweets/sugars. This implied that nutrition education had effect on the consumption pattern of the secondary school students. This finding also showed that nutrition education had effect in reducing the amount of carbohydrates and increasing the consumption of protein foods among the young students. The increase in baked products and pastas consumption could be allowed to enable the students take some snacks while in school during brake time. Increase in the consumption of fat and oil (margarine) should be encouraged as most margarine are fortified with some micro-nutrients. The excessive consumption of sweets and sugars should be discouraged as this could lead to dental carries especially in children and chronic diseases like obesity, diabetes, etc. The increase in the consumption of certain food items especially meat, and fish products and healthy snakes would lead to the healthy growth and development of the secondary school students. This is because, this is another stage of growth spurt, to enable them developing optimally, reduce micro-nutrient efficiencies, stunting and wasting, etc.Conclusion: Nutrition education should be intensified both in schools and community. School feeding programme should be implemented in the state/federal schools, so as to encourage the students to eat variety of meals