Macrobrachium macrobrachion (Herklots, 1851) Class Structure and Sex Ratio in Luubara Creek, Ogoni Land, Niger Delta, Nigeria

Abstract: Macrobrachium macrobrachion class structure and sex ratio was studied in Luubara creek of Ogoni land in the Niger Delta area of Nigeria for a period of two years (January, 2006 to December, 2007. Majority of male shrimps were found in the 8 to 16 mm class. In 2006, the size class (8-16 mm) recorded 232 shrimps and constituted 32.08% of the sample population. However, in 2007 most of the male shrimps occurred in the 12-16 mm class, (157 shrimps) and constituted 28.91% of the sample population. In the females, the dominant size class was 8 to 16 mm. In 2006, a total of 324 females were observed in this size and this constituted 49.24% of the sample population. In 2007, a total of 170 female shrimps were obtained in the 8 to 12 mm size class and this constituted 38.20% of the population. There were no female shrimps caught in the 24 to 28 mm class during the study period. Amongst the berried females most of shrimps were found in the size class of 8-20 mm. In 2006 there were 274 berried females in the 8-12 mm group and this constituted 51.40% of the sample population. In 2007 a total of 167 berried females were caught in 8-12 mm group and this constituted 47.87% of the sample population. The sex ratios of shrimps in Luubara creek were variable. There were more females than males. The overall male to female ratio was 1:1.6. It was only in the month of October 2006 that the numbers of male were more than the female with a ratio of 1 male: 0.9 female. The male to female ratio was more than 1:2 in four months namel

Comparative Evaluation of Batch and Continuous Anaerobic Digesters in Biogas Production from Municipal Solid Waste using Mathematical Models

An investigation was conducted into the suitability of either of the batch or continuous (CSTR) digesters for anaerobic degradation of municipal solid waste (MSW) in the production of biogas. Mathematical models were developed for the design and evaluation of the two systems. The development of the models was based upon a material balance analysis of the digesters'operation. A Microsoft Visual Basic Version 6.0 Programme was developed for the solution ofthe model equations, and the digesters' operations simulated over a range of percentage total solids (PTS) concentration of 4-10% for the CSTR and 4-30% for the batch digester, and fractional conversion of 0.2-0.8. The results of the simulation show that although the amount of methane (0.0764m3) produced per unit volume of the batch digester is about 4 times less than the amount (0.284m3) per unit volume of the CSTR, the cost per unit volume of the batch digester ($5.98) is 6 times less than that of the CSTR ($33.8), suggesting that the overall cost of producing gas with the batch digester would be more economical. So, it was deduced that the batch digester is better suited for the digestion of MSW for biogas production, compared to the CST

A Review of Some Parasite Diseases of African Fish Gut Lumen Protozoa, Coccidioses, Cryptosporidium Infections

Abstract: A review of some parasite diseases of African fish: Gut lumen protozoa, coccidioses, cryptosporidium infections, haemoprotozoa, haemosporidia was carried out from some existing literature to provide fish culturists and the public sector information on some challenges faced in culture fisheries. The Description, taxonomy, diagnosis Life cycles, biology, Epizootiology and control, Protozoans of the gut lumen, Coccidioses, Cryptosporidium Infections, Haemoprotozoa (Haemoflagellates), Haemosporidia -Dactylosoma and Hemogregarines are reviewed in this study

The Zooplankton Species Composition and Abundance in Sombreiro River, Niger Delta, Nigeria

Abstract: The zooplankton species composition and abundance in Sombreiro River, in the Niger Delta of Nigeria was studied for a period of two years (August, 2007-July, 2009), using filtration technique. 25 :m mesh size plankton net was towed from a dugout boat at about 5-105 -1 for about a minute. The net content was washed out into a wide mouth plastic container and preserved in 10% formalin solution after proper labeling. A total of seventeen (17) species belonging to six (6) taxonomic groups were recorded from Sombreiro River. The groups Cladocera and Copepoda were represented by five species each consisting of 29.4% by composition. This was followed by three species of Protozoa (17.6%), two species of Rotifera (11.8%), Decapod crustacean (5.9%) and Euphasiacea (5.9%), one specie each. Copepoda was the highest, 46.5%. This was followed by Cladocera (23.3%). The others were Protozoa (11.2%), Euphasiacea (9.6%), Rotifera (7.9%) and Decapod Crustacean (1.5%). The low zooplankton diversity observed in this study is common in tropical waters. The dominance of cladocera and copepoda in the study area is common to River Nun, in the Niger Delta and Schelde estuary in Belgium. Sombreiro River zooplankton abundance is higher than that of River Nun but lower than that of Imo River in the Niger Delta. These differences are attributed to duration of sampling and natural conditions of the water bodies. The zooplankton abundance was well distributed in the stations except Mysis sp. (Decapod Crustacean) which showed spatial discontinuity in abundance

The Composition in Different Size Groups and Index of Relative Importance (Iri) of Callinectes amnicola (De Rochebrune, 1883) Food from Okpoka Creek, Niger Delta, Nigeria

Abstract: The composition in different size groups, and index of relative importance of Callinectes amnicola food from Okpoka creek was studied for a period of two years (January 2006 -December 2007. Crabs less than 10mm were absent in the catch. Crab appendages, bivalve shells, bivalve tissues, gastropod shells and annelids were absent in smaller crabs (10-19.9 mm) and (20-29.9 mm). Algae cells were absent in crab (40-49.9 mm to 70-79.9 mm) size groups. Crustacean, Pisces and mollusca were common in the stomachs of the larger size group. The numerical method showed that algae cells (46.9%) were most abundant in size group (10-19.9 mm) followed by 20-29.9 mm (33.1% ) size group and 30-39.9 mm (20.0% ) size group. Crustacean (shrimp parts 32.7% and crab appendages 35.2%) was numerically higher in (70-79.9 mm) size class. The frequency of occurrence method showed that, Fish flesh accounted for 19.8% 17.6%, 15.4% 13.2%, 11.0% and 9.9% of the stomach contents in the 30-39.9 mm, 20-29.9 mm, 10-19.9 mm (50-59.9 mm, 70-79.9 mm), 40-49.9 mm, 60-69.9 mm size group respectively. Fish scales occurred most in (70-79.9 mm) size group with a value of 19.4% followed by 15.3% (50-59.9 mm) size group whereas the other size groups had between 10.4% and 14.6% in occurrence. The percentage occurrence of fish bones /spines in 10-19.9mm to 70-79.9mm size groups ranged between 8.7% and 17.4%. The highest (17.4%) was recorded in (40-49.9 mm) size group while the least (8.7%) was obtained in (10 -19.9mm) size group. Bivalve shells (29.5%) and bivalve tissue (28.6%) led in occurrence in (70-79.9mm) size group whereas 28.6% (gastropod shells) encountered in (70-79.9 mm) size group, followed in decreasing order of occurrence by size groups 60-69.9mm (25.0%), 40-49.9 mm (21.2%), 50-59.9 mm (16.3%) and 30-39.9 mm (15.4%). Shrimp parts and crab appendages occurred consistently in (50-59.9 mm to 70-79.9 mm) size groups with the highest values (33.0% and 31.1%) in (70-79.9 mm) size group while the lowest (7.4%) was for (30-39.9mm) size group. Algae cells and higher plant parts accounted for 40.6% and 28.0% respectively of the stomach contents in 10-19.9mm. The point's method that showed shrimp parts contributed 33.3% and 26.3% of the stomach content in the 70-79.9mm and 60-69.9mm size groups respectively. Similarly, crab appendages accounted for 35.5% in 70-79.9mm size group and 31.2% in 60-69.99mm size group. In the 70 -79.99mm size group, fish flesh was 38.0%, fish scales 18.9% and fish bones/spines (18.9%) respectively. The highest values bivalve shells (31.9%) and bivalve tissues (32.1%) were recorded in (50-59.9mm) and 60-69.9mm) size groups respectively. Whereas the 10-19.9mm and 20-29.9mm size groups had no bivalve shell or tissue in their stomachs. Gastropods shells values ranged from 17.7% to 23.2% by points with the highest (23.2%) recording in size groups (30-39.99 to 70-79.99 mm) while the least (17.7%) was in (70-79.9 mm) size group. Annelids scored between 4.2% and 37.5% points amongst (30-39.9 mm to 70-79.9 mm) size groups with the highest and lowest values recorded in (70-79.9 mm) and (30-39.9 mm) size groups respectively. Index of relative importance (IRI) in the food items showed importance ranged from 7.14% to 0.07% in 2006 with the highest percentage index of relative importance recorded for bivalve shells (7.14%) and the lowest (0.07%) for the annelids. On the contrary, the percentage index of relative importance values varied from 0.34% to 21.67% based on increasing order of importance in 2007. Bivalve shells had IRI value of 427.44 (21.67%) whereas Annelids had IRI valve of 6.66 (0.34%). Similarly the highest value of 21.67% and lowest (0.34%) were recorded for bivalve shells and annelids respectively

Effect of Total Solids Concentration of Municipal Solid Waste on the Biogas Produced in an Anaerobic Continuous Digester

Municipal Solid Waste (MSW) contains a relatively large amount of organic matter, which decomposes by the actions of microorganisms under anaerobic conditions to produce biogas. The total solids (TS) concentration of the waste influences the pH, temperature and effectiveness of the microorganisms in the decomposition process. This work investigated various concentrations of the TS of MSW in an anaerobic continuously stirred tank reactor (CSTR) and the corresponding amounts of biogas produced, in order to determine conditions for optimum gas production. Five laboratory-scale anaerobic batch digesters of 5 litres volume each were set up for the digestion of 2kg of shredded MSW diluted to a %TS concentration of 26.7%. The results from the batch experimentation were adapted to the design of a CSTR for the digestion of MSW. The CSTR was simulated over a range of %TS concentration of 4-10, at a maximum fractional conversion of 0.8 to cater for system inefficiencies. Mathematical models were developed for the process and solved using the Microsoft Visual Basic version 6.0 Programme. The results show the amount of biogas produced as a power function of the %TS concentration, indicating that as the process continues, a time comes when any marginal increase in the %TS concentration would no longer contribute to the increasing volume of biogas produced. The results further show that, given the limiting upper boundary of the %TS concentration, optimum biogas production in a CSTR digesting MSW cannot be ascertained with the concentration of the %TS alone

Some Growth Parameters of Macrobrachium mcrobrachion (herklots, 1851) from Luubara Creek in Ogoni Land, Niger Delta, Nigeria

Abstract: Some Growth parameters of Macrobrachium mcrobrachion from Luubara Creek in Ogoni Land, Niger Delta, Nigeria was studied for a period of two years (January, 2006 -December, 2007. The parameters were evaluated using different applications in the FiSAT package such as the Powell-Wetheral plot; the ELEFAN 1 Scan, and the Non-Seasonalized Version of the Von Bertalanffy growth function (VBGF) to ensure accuracy. Powell-wetheral plot gave estimates of L4 as 81.53 mm TL), K was 2.06 per year, Z/K was 1