Francis K. E. Nunoo

A multi-gene dataset reveals a tropical New World origin and Early Miocene diversification of croakers (Perciformes: Sciaenidae)

Widely distributed groups of living animals, such as the predominantly marine fish family Sciaenidae, have always attracted the attention of biogeographers to document the origins and patterns of diversification in time and space. In this study, the historical biogeography of the global Sciaenidae is reconstructed within a molecular phylogenetic framework to investigate their origin and to test the hypotheses explaining the present-day biogeographic patterns. Our data matrix comprises six mitochondrial and nuclear genes in 93 globally sampled sciaenid species from 52 genera. Within the inferred phylogenetic tree of the Sciaenidae, we identify 15 main and well-supported lineages; some of which have not been recognized previously. Reconstruction of habitat preferences shows repeated habitat transitions between marine and euryhaline environments. This implies that sciaenids can easily adapt to some variations in salinity, possibly as the consequence of their nearshore habitats and migratory life history. Conversely, complete marine/euryhaline to freshwater transitions occurred only three times, in South America, North America and South Asia. Ancestral range reconstruction analysis concomitant with fossil evidence indicates that sciaenids first originated and diversified in the tropical America during the Oligocene to Early Miocene before undergoing two range expansions, to Eastern Atlantic and to the Indo-West Pacific where a maximum species richness is observed. The uncommon biogeographic pattern identified is discussed in relation to current knowledge on origin of gradients of marine biodiversity toward the center of origin hypothesis in the Indo-West Pacific.

Marine Fisheries Catches in Ghana: Historic Reconstruction for 1950 to 2010 and Current Economic Impacts

Ghana has a long fishing tradition, including industrial fishing. After many of the countries where Ghanaian fleets were actively fishing declared an Exclusive Economic Zone in the 1980s, the distant-water fleet of Ghana returned to its home waters, precipitating a collapse of some local stocks. While official catches reported to the FAO document this decline, the catches of other sectors (artisanal, subsistence, and recreational fishing) were not reported, their contribution to the livelihoods of Ghanaians was simply not documented, and their impact on fish stocks overlooked. Herein, total catches were estimated at 20.8 million tonnes between 1950 and 2010 compared to 11.8 million tonnes reported to the FAO. Subsistence catches, notably from coastal lagoons represented the bulk of unreported catches and seemed to have increased overall during this period, while the artisanal and large-scale sector catches decreased. Furthermore, the economic contribution of artisanal fisheries to Ghana is declining mainly due to use of non-sophisticated technology and activities of industrial fisheries making already poor communities poorer while industrial (particularly tuna) fisheries are increasing their profitability margin due to high technology being adopted and operating in less exploited parts of the continental shelf of Ghana. Accurate catch statistics and a better understanding of the contribution of the marine fisheries sector are needed for sustainable management of the fishing industry in Ghana and its contribution to the Ghanaian economy.

A PRODUCTION FUNCTION ANALYSIS OF POND AQUACULTURE IN SOUTHERN GHANA

Aquaculture is considered an alternative to making up the shortfall in supply of fish in Ghana. The Cobb-Douglas production function, which relates production output to several independent input variables, was used to determine the inputs that affect productivity. A survey was conducted on pond farmers selected from four regions of Ghana. Empirical results show stocking rate as the most significant input that affected production. Aquaculture exhibited increasing returns to scale over the period of the study, meaning an increase in inputs will more than proportionately increase the output. Estimates of the marginal physical productivity of the inputs indicated stocking rate should be increased while decreasing feed and labor use in order to increase productivity.

Schoolchildren's Use of Poetry and Paintings in Conveying Environmental Messages.

Pupils aged 12–14 from the University of Ghana Primary and Junior High School conducted studies off the coast adjacent to Accra, including a field visit to explore the effects of climate change on the country’s biology, ecology and physical environment. They composed poems and made paintings about the coast and sea as means of conveying their views about climate change. Content analysis of these compositions using a count of word descriptors revealed that particular themes or messages tended to recur in both poems and paintings. Both of them depicted Ghana as a beautiful place that was suffering from the negative impacts of climate change. There were, nevertheless, differences in the ways in which these two art forms were used to convey messages. For example, poems used words to stress the national importance of the seas, their value as assets of God’s creation and the need for everyone to work together in order to manage them at sustainable levels. Paintings, on the other hand, used images to identify specific causes of pollution and climate change and to illustrate the uses of the seas. It is argued that the creative arts should play a more significant part in the science curriculum. Not only could they bring science to life in the classroom, but they could provide powerful mechanisms whereby young people communicate their own views on environmental issues to other members of society, especially non-specialists.

Towards municipal solid waste source separation at the household level in Accra, Ghana

Municipal solid waste source separation at the household level has been endorsed as the way forward by all stakeholders in the waste management sector in Ghana. The study using waste stream analyses and laboratory investigations assesses the feasibility of this intervention in the Accra Metropolitan Area which has been divided into three income zones. The mean waste percentage composition was dominated by 75% organic and 8% plastic waste. Mean values for total carbon, available carbon, nitrogen, C/N and moisture values were 90.2, 45.1, 1.83, 27.6 and 51.7% respectively. The low income high density zone recorded higher separation levels followed by high income low density and middle income low density zones. The study recommends that the policies to guide its successful implementation should be supported by public education and the right infrastructure.

Effects of stocking density on growth and survival of young Gulf killifish in recirculating aquaculture systems

ABSTRACT Gulf killifish, Fundulus grandis, is a hardy marine baitfish with established rearing techniques in ponds and static pools, but there is little information about the use of recirculating aquaculture systems (RAS) for growing killifish.The current trial investigated the effects of stocking density on growth and survival of young killifish in RAS. Young fish (28-day posthatch) of 51.6 ± 0.9 mg (mean ± SE) were stocked at 2, 5, 8, and 11 fish/L in 31 L tanks in RAS with triplicate groups for 16 weeks. Cannibalism was a major problem in the study, which increased with increasing initial stocking density, affecting survival negatively. Survival decreased (P < 0.03) with increasing initial stocking density and culture period. At the end of the trial, the 2, 5, 8 and 11 fish/L initial stocking density reduced to 1.66, 1.42, 0.86, and 0.74 fish/L respectively. A significant linear relationship existed between the initial stocking density and weight (y = 0.077x + 2.3; R2 = 0.8; P = 0.003), whereas an inverse relationship occurred between initial stocking density and survival parameters (y = −9.43x + 97.4; R2 = 0.89; P < 0.001). From the trial, the optimum density for culturing young of Gulf killifish in RAS appears to be around two fish/L.

A novel approach in regional tuna fisheries management using low resolution satellite data: A case study for the Gulf of Guinea

The tuna fisheries in the Gulf of Guinea provides huge economic benefits through fish trade and food security. The region, an important spawning site and migratory path for three dominant tuna species i.e. Skipjack (Katsuwonus pelamis), Yellowfin (Thunnus albacares) and Bigeye (Thunnus obesus), has high incidence of illegal fishing practices, in addition to poor surveillance and monitoring of fisheries resources. Adopting conservation methods for effective management of the tuna fisheries requires an understanding of their thermal preference, foraging behaviour and migratory patterns. Using tuna catch data from 2004 to 2006 in the eastern equatorial Atlantic we have described the spatial distribution of tuna catch and thermal range associated with these distribution from low resolution remotely sensed sea surface temperature data. Tuna in the equatorial Atlantic are concentrated at the major upwelling centers off the coast of Ghana and equatorial Atlantic at surface temperatures of 23 to 28°C.