Determination of Trace Metals Quality of Sources of Drinking Water in Some Selected Communities in the Akuapem South District of the Eastern Region, Ghana

The study was undertaken in three communities namely Adamrobe, Aburi and Pokrom-Nsaba, all located in the Akuapim South District of the Eastern Region. These communities depend on streams, wells, and springs for their drinking water requirements. The objective of the study was to assess the trace metals quality of the drinking water sources used by the communities. Water samples from these sources (streams, wells, and springs) were analyzed over a period of twelve months for various water quality parameters including the following trace metals: lead (Pb), cadmium (Cd), zinc (Zn), & arsenic (As), following standard methods designed in APHA, AWWA, and WEF. The results of the study revealed that, most of the mean levels of trace metals registered from the water samples were below the World Health Organization (WHO) and Ghana Water Company Limited (GWCL) recommended critical limits for drinking water standards. The low level of trace metals recorded in the water samples was due to the absence of industrial and mining activities in these communities and their environs. The high level of lead registered in ABSP was as a result of the low pH discovered in the water sample for that station. It is therefore recommended that further study be conducted to track the long term health effects of the trace metals in the drinking water sources used by the study communities. Keywords: Trace Metals Quality, Sources of Drinking Water, Selected Communities, Akuapem South District, Eastern Region, Ghana

Pre-Impoundment Fish Stock Assessment of the Black Volta: A Contribution to Fisheries Management of Bui Reservoir in Ghana

A length-based fish stock assessment of the Black Volta River in Ghana was undertaken prior to its damming at Bui in 2011. The approach involved estimation of the population parameters and exploitation rates of dominant fish stocks using TropFish R. The targeted species were: Alestes baremoze, Hydrocynus forskalii, Hemisynodontis membranaceus and Labeo coubie. The estimated asymptotic length (L∞) ranged from 30.8 – 48.2 cm standard length (SL) with derived longevity of 11 – 27 years for the assessed species. The estimated growth coefficient (K) value ranged from 0.10 – 0.25 yr-1 which suggested slow growth rates. The estimated length at first capture (Lc50) was lower than the length at first maturity (Lm50) for all the assessed fish species which suggests the presence of recruitment overfishing within the fish stocks. The total mortality rate (Z) was relatively high ranging between 0.51 and 1.34 yr-1 suggesting that the stocks were over-exploited during the pre-impoundment period. The exploitation rate (E) for the assessed fish species were lower than the maximum exploitation rate (Emax) which indicates that the species are far from collapse. These estimates are baseline scientific information for designing a Fisheries Management Plan for the Bui reservoir. Meanwhile, alternative livelihood and employment opportunities such as cage fish culture are to be explored to reduce the fishing pressure on the reservoir

Prevalence of parasitic infections on cultured Nile tilapia, Oreochromis niloticus (Linnaeus, 1758) In Bong County, Liberia

This study investigated the prevalence rate, relative abundance and mean intensity of par­asites infecting cultured Nile tilapia Oreochromis niloticus L. in three fish farms, Gbarnga, Warta and CARI in Bong County, Liberia. Organs from thirty fish samples were exam­ined from September 2016 to February 2017, along with water quality parameters. Results showed the occurrence of seven parasites including protozoans, monogeneans, digeneans, cestodes, hirudineans, nematodes and crustaceans which were organ specific in terms of infection. The prevalence of the parasites varied seasonally, with the highest numbers oc­curring in November-January. The low prevalence rate, relative abundance and mean in­tensity of the parasites showed no threat to fish farmers in Liberia. All the water quality parameters were at desirable levels for the culture of the fish except nitrite, which was beyond the threshold for sustainable fish culture. It is therefore concluded that although parasitic infections in the three farms in the Bong County were low, best farm management practices are essential

Indeterminate status of West African populations of inshore common bottlenose dolphins <i>Tursiops truncatus</i> caution against opportunistic live-capture schemes

The limited information available on the status of inshore common bottlenose dolphins Tursiops truncatus along the coasts of West Africa is reviewed. Although reported from at least ten countries, it is unclear whether their distribution is continuous. Population structure and genetics have not been studied, however cranial morphology suggests that the West African dolphins differ from North Sea bottlenose dolphins. Mean group sizes are small (3.19 – 12.91 individuals/group) and are smallest in Guinea-Bissau. There are no estimates of abundance but by analogy with a well-studied population in Sarasota, Gulf of Mexico, the Guinea-Bissau population may number only in the hundreds. It is essential that scientific estimates be obtained through dedicated surveys. In some areas of Guinea-Bissau with a high density of fishing activities, bottlenose dolphins are now less frequently encountered than they were in the recent past. Key parameters besides abundance, including population identity, bycatch levels and other anthropogenic threats need to be documented and quantified before any deliberate exploitation is considered. A small-scale, botched live-capture operation in Senegal in 2003, in which all dolphins died, serves as warning against such opportunistic schemes. In management terms, live-capture operations are equivalent to hunting and multi-year, large-scale removals of bottlenose dolphins in Guinea-Bissau would have the potential to effectively extirpate the wild population from its waters

Observations on the population dynamics of Hemisynodontis membranaceus (pisces: mochokidae) in stratum vii of Lake Volta

The population dynamics of the mochokid, Hemisynodontis membranaceus (Geoffroy St. Hilaire, 1809), a dominant fish species in purse seine or “winchnet” catches in Stratum VII of Lake Volta, were studied using length frequency data. Using the FAO-ICLARM Stock Assessment (FISAT) Software, the von Bertalanffy growth parameters, L¥, K and to were estimated for the fish as 44.0 cm Standard Length, 0.55 per year, and 0.26 year respectively. The natural mortality coefficient, M was found as 1.12 year-1; fishing mortality coefficient, F= 2.91 year-1; and the total mortality coefficient, Z found as 4.03 year-1. The exploitation rate, E = F/Z was thereby found as 0.72 indicating that the species is over-exploited requiring immediate management attention. At least 4 year groups or cohorts were found to occur on the fishing grounds which have a longevity of about 5 years. The average annual yield of H. membranaceus by winchboats (purse seine) is estimated as 4,000 tonnes. Information available from Thompson and Bell analysis suggest that a Maximum Sustainable Yield (MSY) of 4,800 tonnes per annum of H. membranaceus may be achieved when the present fishing effort of winchboats is reduced by about 20%. Any further increase in the effort is not expected to increase the average yield. JOURNAL OF THE GHANA SCIENCE ASSOCIATION Volume 1 Number 2, January (1999) pp. 43-5