ABSTRACT. Many countries in sub-Saharan Africa have areas of significant ecological importance that overlap with pressing development needs and high levels of natural resource dependence. This makes the design of effective natural resource governance and management systems both challenging and critical. In Ghana, this challenge is made more complex by the necessity of connecting formal, state-led systems of governance with Ghana's informal governance systems through which customary authorities exert considerable control over land and resources. We present findings from two multimethod research projects in two regions of Ghana that have significant issues related to resource exploitation and that have experienced extensive management interventions. The goals of the research were to characterize the social-ecological traps from a local perspective, to describe how governance and management structures interact with and relate to those traps, and to discuss the strategies used and challenges encountered when community-based natural resource management initiatives seek to reverse persistent social-ecological traps. In both case studies, participants described persistent cycles of resource dependence, overexploitation, and unsustainable land-use practices, which are exacerbated by illegal logging, intensive agricultural development, and population growth. Findings highlight how natural resource management is constrained by a lack of capacity to implement and enforce state policies, ongoing tension between customary and state institutions, and ambiguity regarding management responsibility and resource tenure. Interventions included targeted governance reform that centred on improving linkages between customary and state institutions, new and nonlocal actors, and complementary investments in capacity building and training. We conclude with a discussion of implications for the design of effective natural resource governance regimes in Ghana and beyond.

This chapter describes the application and optimization of the recirculating aquaculture systems (RAS) technology in the marine sector, in particular the development of urban recirculating mariculture for high-value marine fish. The system's performance and economic feasibility were tested in a pilot urban mariculture programme in the city of Baltimore (Maryland, USA), studying the Mediterranean gilthead seabream (Sparus aurata [Pagrus aurata]) as its candidate species. This fish, a non-native species in North America, commands a local retail price of up to US$20/kg. The Baltimore Urban Recirculating Mariculture System was designed to produce high-value marine fishes that cannot be farmed in net-pens or ponds, to use municipal pre-existing infrastructure and services, to have the ability to locate anywhere and to maximize the re-use of water. The life support system consisted of a particle removal microscreen drum filter, a moving bed nitrifying reactor, an ozone-based protein skimmer and a low head oxygenation unit. Conditioned artificial seawater was automatically delivered to provide the desired salinity and temperature. pH, ozone levels and photoperiod were continuously monitored and adjusted. Strict biosecurity was achieved by disinfecting all waste effluents before their discharge to the municipal sanitary sewer. Using this system, gilthead seabream of two strains were grown from 0.5 to 400 g commercial size in 268 days (first strain) and to 410 g in 232 days (second strain). Survival rates exceeded 90% and food conversion rates varied from 0.87 to 1.89, depending on fish growth. Growing densities ranged from 44 to 47 kg/m3 at 7-10% daily water exchange rates. Total ammonia and nitrite levels remained significantly below stressful concentrations. To increase the economic feasibility of the system, microbial communities associated with biofiltration were studied in an effort to improve nitrogen removal and thus maximize re-use of the saltwater. New bacterial-mediated nitrogen removal processes are described herein and addition of an anaerobic denitrification unit was also studied, both of which enhanced the ability to minimize saltwater discharge. The environmentally compatible recirculating mariculture pilot system described here can be scaled up to cost-effectively produce high-value marine fish in an urban setting.

The development and expansion of a viable marine shrimp-farming industry in the USA has been a goal of the US Marine Shrimp Farming Program research consortium for many years. Production research has focused on the development of systems for open pond culture, and a small but stable industry has developed based on these technologies. New advances have facilitated the intensification of production, reduction or elimination of water exchange, application of biosecurity protocols and stocking of high-health and genetically improved shrimp, all of which currently serve as the foundation for the US shrimp-farming industry. Based on these research advances, consortium scientists have shifted resources over the past few years to re-evaluate super-intensive raceway production technologies. At the Waddell Mariculture Center (WMC) in South Carolina, and the Oceanic Institute (OI) in Hawaii, prototype and pilot-scale systems have been operated over the past 3 years. In recent WMC trials, production of up to 3 kg/m2 was demonstrated with survival ranging from 55 to 71%, and harvest sizes from 14.6 to 17.1 g in 137 days. At harvest, production results for the latest trial based on the stocking of nursed 1 g juveniles were: survival=91%; mean weight=16.6 g; FCR=1.54; mean growth/week=1.44 g; and yield=4.50 kg/m2. At OI, three trials have been conducted with increasing stocking densities ranging from 100 to 300/m2. In the most recent 85-day trial, juvenile shrimp (∼2 g) grew to a harvest weight of 19.9 g with a mean growth rate of 1.47 g/week. Productivity of the system reached 5.2 kg/m2 and survival was 86.3%. All of these trials are based on high-output, minimal water usage, enclosed raceway designs that assure biosecurity and provide excellent potential for application in non-traditional, urban and/or contaminated environments. The demonstration trials described in this chapter, along with supporting research on breeding, microbial dynamics, feeds, engineering, financial feasibility and marketing, have brought these technologies to the point of commercialization. Urban and peri-urban application of these technologies in the USA could offer opportunities for the development of integrated marketing initiatives to improve the outlook for financial viability.

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