Daniel Adjei-Boateng

Assessment of sand and stone mining along the coastline of Cape Coast, Ghana

Mining of sand and stone from the coasts provides an inexpensive source of materials for the construction industry while providing income to contractors. However, these activities come at a cost to the coastal environment and pose a threat to the tourism industry along the Ghanaian coast. This paper identified the various types of coastal sand and stone mining activities, the level at which they are undertaken and covers the trends in coastal erosion along the coast of Cape Coast, Ghana. ArcGIS (ESRI, Redlands, CA, USA) and Digital Shoreline Analysis System (DSAS; ESRI) tools were used to determine short-term (2005–2012) coastline changes using 2005 and 2012 coastlines data. This study estimates that tipper-truck-based beach sand mining activities alone account for the loss of about 285,376 m3/year of sand from the littoral zone in the Cape Coast area. It was also established that the average erosion rate for the Cape Coast area within the seven year period is 0.85 m/year with two areas recording high erosion rates of 4.35 m/year and 4.25 m/year. The study concludes that sand mining is the main cause of erosion along the coastline of Cape Coast.

Coastal Erosion in Ghana: Causes, Policies, and Management

ABSTRACT Coastal erosion is a serious problem that affects the safety and livelihoods of many coastal dwellers along Ghanas coast. Despite the fact that coastal erosion is a natural phenomenon, erosion trends have been largely aggravated by human-induced factors. This study analyzed shoreline change rates for three neighbouring coastal communities in the Central region of Ghana; Elmina, Cape Coast and Moree. Two epochs were analyzed, 1974–2012 (medium-term) and 2005–2012 (short-term), using ArcGIS and Digital Shoreline Analysis System. Overall, the entire study area recorded average shoreline change rates of −1.24 myear−1 and −0.85 myear−1 in the medium-term and short-term period respectively. Less consolidated shoreline segments recorded higher erosion rates in both periods while cliffs and rocky segments experienced very little erosion or high stability. Because shorelines undergoing chronic erosion do not fully recover after short-term erosion events such as storms, facilities located close to such shorelines are threatened. Taking a proactive approach to coastal erosion management, such as coastal sand mining prevention, inter-sectoral land use management and adopting a construction setback approach may be prudent for the long-term management of the coast since this recognizes future shoreline changes and safeguards coastal landscape for other uses.

Sexual strategy in the freshwater bivalve Galatea paradoxa (Donacidae) from the Volta River estuary, Ghana

The reproductive biology, sexual strategy and sex ratio of the freshwater donacid Galatea paradoxa in the Volta River estuary, Ghana, was studied from March 2008 to February 2010. Histological observations of the gonads showed that G. paradoxa is gonochoristic with dominance by females (80%) and a high incidence of hermaphrodites (9.4%) for individuals ranged between 20 and 82 mm in shell length. There was a single spawning event between July and October. Gametogenesis started in December, progressing steadily to a peak in June–July when spawning began, until November when individuals were spent. The dominance of females coupled with the high incidence of hermaphroditism may be a reflection of populations subjected to increasing fishing pressure and over-exploitation.

Processing techniques of selected oilseed by-products of potential use in animal feed: Effects on proximate nutrient composition, amino acid profile and antinutrients

The effects of processing by autoclaving (AC), soaking (SK), short-term fermentation (S-TF, 4 d) and long-term fermentation (L-TF, 14 d) on the nutritional composition, amino acid profile and some antinutrients were determined for cottonseed meal (CSM), groundnut meal (GNM) and groundnut husk (GH) in this study. After processing, crude protein content improved by 11% after L-TF, and crude lipid content 25% after SK for CSM; crude protein content improved by 27% after S-TF and L-TF, and crude lipid content 13% after SK for GNM. Soaking and fermentation were shown to significantly increase essential amino acid contents by 44% (SK, methionine) in CSM and 46% in GNM (L-TF, histidine). Phosphorus content was reduced by 59% in CSM and 57% in GNM by L-TF. All processing techniques, with the exception of AC, reduced phytic acid and gossypol contents in CSM and GNM. It was concluded that SK and fermentation were simple, cost-effective, and efficient ways to improve the nutritional value of the selected oilseed by-products.

Evaluation of Locally-available AgroindustrialByproducts as Partial Replacementsto Fishmeal in Diets for Nile Tilapia(Oreochromis niloticus) Production in Ghana

Objective: This study assessed the potential of three widely-available local oilseed byproducts, soybean (SBM), copra (CM) and palm kernel meals (PKM) as partial replacements of fishmeal in Nile tilapia (O. niloticus) diets in terms of their digestibility and effects on growth and nutrient utilization. Methods: Apparent digestibility coefficients (ADCs) were determined using chromic oxide as an inert marker in test diets formulated to contain 30% of each of the test ingredients by weight and 70% of a fishmeal-based reference diet. The 8-week growth trial evaluated the effects of partial replacements of fishmeal by the oilseed byproducts at different dietary inclusions. The soybean meal diets were formulated with the soybean meal contributing 25% (SBM25) and 50% (SBM50) of total dietary protein. Copra and palm kernel meals each contributed 10 (CM10 and PKM10) and 20% (CM20 and PKM20) of total dietary protein in their respective diets. The test diets were compared to a control diet with fishmeal as the sole protein source. Results: Nutrient digestibilities of the test ingredients were generally significantly higher for the soybean meal than the copra and palm kernel meals. The ADCs of the soybean, copra and palm kernel meals were; protein, 90.57%, 69.36% and 61.12; lipid, 96.14%, 95.64% and 95.85%; fibre, 96.74%, 77.61% and 55.07% and energy, 91.99%, 73.61% and 75.14% respectively. All the dietary treatment groups recorded significant growth at the end of the trials with the fish in the control and SBM25 groups more than tripling their respective mean initial weights. All the other treatment groups more than doubled their mean initial body weights. Daily growth rates ranged from 1.40% day-1 for the PKM20 group to 2.26% day-1 for the control group. Conclusion: The study has shown that the test ingredients can partially replace fishmeal in Nile tilapia diets without considerably compromising diet digestibility and carcass traits although higher dietary levels of the oilseed byproducts negatively affects growth.