Aquaculture

This study evaluated water quality of the Ashaiman reservoir and fish holding facilities at a hatchery close to the reservoir. Physicochemical parameters, nutrients, productivity and fish pathogenic bacteria were determined monthly. Physicochemical parameters at all sites were within suitable range for fish production. Nutrient levels were however significantly higher in the culture facilities than the reservoir (P<0.05). Productivity levels and pathogens were above the suitable limit in hatchery tanks but within acceptable range in the reservoir. A water quality index (WQI) of 100.01 for the reservoir is indicative of poor quality. Pathogenic bacteria load was high and should be of concern to the fish hatchery operations.

Biodegradation and trace element content of three different animal wastes were evaluated in green house study. The study was a factorial experiment in a randomized complete block design (RCBD) with three different rates of 0, 5, 10 and 20 tha-1 each for poultry manure, pig manure and cow dung. Each treatment was replicated three times. The result showed that biodegradation rate of the wastes varied while poultry manure (PM) and pig manure (PG) decomposed fast, cow dung (CD) decomposed relatively slow. Hence nutrient release ability will be more on the PM and PG than in CD. The result of the study showed that it will require more oxygen to degrade CD than PG or PM thus cow dung has higher pollution potential followed by PG and PM. The result also showed that the incorporation of the animal wastes enriched maize shoot with trace metals. These metals at above critical levels are toxic to animals and human beings.

The present study was conducted to investigate in monitoring the effect of vegetable wastes, Probiotics and Bioflocs on the growth and performance parameters of Pacific white shrimp Litopenaeus vannamei in 90 day feeding trail experiments. Due to the addition of vegetable wastes, Probiotics and Bioflocs into the culture operation significantly increased the growth potentials in shrimp. The vegetables are known to contain biomolecules including lipids, carbohydrates, proteins, minerals, vitamins and phytonutrients which were forming as rich sources to shrimp growth and maintenance. In the present study the vegetable wastes were substituting the fishmeal contents in the feed formulation and also successfully catering the needs of the growth, molting, metabolic requirements of shrimp. Due to the addition of probiotics and bioflocs into the culture operation also facilitates not only the maintenance of hygienic aquatic environment and also increases the production of heterotrophic bacterial growth and large quantities of planktonic forms, which in turn will be useful as supplementary feeding materials and subsequently increase not only the growth rates and also productivity. The growth parameters such as weight gain, specific growth rate, feed conversion efficiency, protein efficiency rates were significantly (P<0.05) higher in probiotic and biofloc added feeds compared to vegetable waste formulated feed. Feed conversion ratios were shown to be decreased in probiotic (2.15) and biofloc (1.93) added feeds compared to vegetable waste (2.54) formulated feeds in the present investigation. The energy utilization parameters, such as feeding, absorption, conversion, excretory and metabolic rates were significantly (P<0.05) higher compared to vegetable waste incorporated control feed. So, vegetable wastes may be considered as an ideal replacement for fishmeal in the formulation of shrimp feed along with the addition of probiotics and bioflcos for successful promotion of growth potentials for shrimp L. vannamei culture operation.

The feeding habit and diet of Brachydeuterus auritus at Apam in the central region of Ghana was investigated over an 8 months period using the Index of Preponderance. Shrimp was found to be the most preferred food item accounting for 59% occurrence by number, with annelids and blue green algae being the least preferred accounting for 7% each. In the same vain, the most ranked food item using the Index of Preponderance was shrimps followed by fish with annelids recording the least rank. Correlation between food items number and the nutrient rich upwelling season was observed. Continuous study of the feeding preferences of this species is recommended owing to its importance to both the Ghanaian marine catches and as a relatively cheap source of animal protein.

Macro-benthos communities are often threatened by environmental changes which are associated with pollution, erosion and siltation. Since paucity of information was available on Itapaji Reservoir benthic macro-invertebrates composition, a pertinent study to ascertain the quality of the water for its sustainable management becomes crucial. The reservoir was monthly sampled for benthic macro-invertebrates (BMI) from April, 2013 to March, 2015 at five purposively selected stations. Samples were collected using Van-Veen grab (surface area, 0.6m2), sieved (mesh size, 0.5 mm), sorted, identified using standard identification keys, and counted macroscopically. Species diversity was determined with Shannon Weiner’s Index (H). Data were analysed using descriptive statistics, student’s t-test, and ANOVA at ?0.05. Two phyla comprise of seventeen species of BMI were recorded with moderately intolerant benthic macro-invertebrates dominating. Higher macro-benthos organisms were recorded in the rainy season with Chaoborus larvae dominated the assemblages in both seasons. All the encountered benthos differed significantly at p<0.05 across the sampling stations, while sampling station 3 recorded the highest abundance. The order of dominance coupled with Shannon Weiner’s diversity index of less than 3.0 revealed that the habitat is unstable, and perturbed due to run-off of anthropogenic material from the adjourning land.

The present study aims to evaluate the microbiological quality of smoked fish from some lake villages near Lake Ahémé. To do this, samples of smoked fish were taken at different sites, followed by microbiological analyzes. The results obtained after the surveys showed, two technological variants of smoking that the fish is lean or fat. Those resulting from the evaluation of the microbiological quality of the fish reveal the presence of several microorganisms including total mesophilic aerobic flora, total coliforms, staphylococci with maximum values of 320.102 cfu / g for coliforms and 280.102 cfu / g for Staphylococci exceeding the normative criteria. It also showed the presence of the fungal flora, the complete absence of fecal coliforms and sulphite-reducing anaerobes in all the samples studied.

The impacts on habitat and living species (fish, shrimp) related to the disposal of untreated sewage by municipalities and discharges of solid waste was studied by assessing the whole organic matter of the sediments (OM), Chemical Oxygen Demand (COD), Suspended Materials (SM), nitrogen pollution indicators (nitrate-NO3-, nitrite-NO2-, ammonium-NH4-), phosphated (ortho-phosphate ions- PO43-), sulphide (sulphate-SO42-, sulphite SO32-, sulphides S2-) of water and total Pb contents of water and sediments of Lake Nokoué. The organic matter content of sediments (19600 to 17164 mg / kg) and COD (130 to 1880 mg/L) of water are very high and indicate an increase in organic pollution of the lake compared to in previous years (Youssao, 2011, Mama et al., 2011). The strong variations in pH are dependent on the contributions of marine origin (basic to neutral) and the mineralization of the organic matter (pH < 7) in the areas of human occupation resulting in a greater or less mobility of the residues of metals in making sulphur available in its reduced form (sulphide and sulphite). The assessment of pollution indicators in the central part of the lake shows that it is heterogeneous in terms of source and impact of pollution. The sediment Pb concentration (Pbsed) / concentration of Pb in water (Pbw) ratio, represented by Pbsed/Pbw ratio shows that lead is 200 to nearly 1000 tiSM more concentrated in sediments than in the water showing a predominance of the organic form of Pb in the ecosystem of Nokoué lake. Indeed, organic lead residues are massively released into this ecosystem by oil traffickers who use OMorized canoes to transport their products from Nigeria.

The study of mineral contents of fresh and dried tilapia fish (Oreochromis niloticus) from Mcaiver Market, Warri South Local Government Area of Delta State, Nigeria were determined. The tilapia fishes were shared into two parts: one part was used to determine the mineral content of the fresh fish and the other part was oven dried before the analysis of mineral contents of both fishes. The minerals detected were in the order Na>Ca>K>Mg>Zn>Fe. It was observed that dried tilapia fish was more nutritional than the fresh tilapia fish. Dry tilapia fish should be consumed rather than fresh tilapia fish for proper nourishments.

This study established the association between fish farming management practices and fish yield in Kakamega County, Kenya. The results were that fish farmers who record the highest fish harvest of over 400 Kgs of fish output per 300 m2 fishpond are those who check water quality at their ponds and apply corrective measures; and those who get their fingerlings from accredited sources. The success of fish farming as an economic livelihood activity in Kakamega County depends on the proper application and appropriate implementation of fish farming management practices. These include management of water and management of the production units through appropriate stocking, feeding and record keeping.

In this study, histological examination of the testicles and cellular tissue changes of sperm cells in the spermatogenesis phase of zebrafish are aimed. In this respect; the microscopic structure of the testicles, the position and form of the cells belonging to spermatogenic string, tissue-generating structural cells, and these organisms are examined with the light microscope. All the phases of spermatogenesis are classified as spermatocytogenesis, meiosis and spermiogenesis taking all the phases and histological development of the cells into consideration. All the cells belonging to these phases are seen in separate groups in seminiferous tubules. It is found out that there are somatic cells around spermagony. And spermatogenic cells return into spermatogenic string cells respectively (primer spermatocyte, secondary spermatocyte, spermatide and sperm organisms) by meiosis.