Socio-economic implications of the fish export trade on the fishers and fisheries of Lake Victoria in Uganda

The purpose of this study was to investigate the implications of the fish export trade on the fishers and the fisheries resources of Lake Victoria, Uganda with respect to sustainability. Eight fish processing factories and ninety fishers were qualitatively investigated. Socio-economic characteristics of fishers and the economic characteristics of fish factories formed a basis for the analysis. Results of the research indicate that there is a relationship between the growth in fish export trade, particularly the growth in industrial fish processing (for export) and declining fisheries resources of the lake. However, whether or not that impact is positive or negative, and to what extent there is an impact, is highly dependent upon the underlying socio-economic considerations of the fishers to the process. The fish-ban imposed by the European Union countries was particularly decried by fishers and factory owners as the main cause for the present poverty among the fishers. Fundamentally, several conflicting issues: ecological, physical and economic activities are a threat to the sustainability of the Lake Victoria fisheries, and for all that depend on and interact with the lake. There is urgent need to address the immediate issue of the growing riparian population and the global fish trade, to educate and train all the relevant actors in appropriate fisheries management techniques. Attitudes of fishers towards the fish factory developments are positive and this is a way forward for co-management for the sustainability of the fisheries resource.

The ecological impact of different mechanisms of chronic sub-lethal toxicity on feeding and respiratory physiology

Sub-lethal toxicity tests, such as the scope-for-growth test, reveal simple relationships between measures of contaminant concentration and effect on respiratory and feeding physiology. Simple models are presented to investigate the potential impact of different mechanisms of chronic sub-lethal toxicity on these physiological processes. Since environmental quality is variable, even in unimpacted environments, toxicants may have differentially greater impacts in poor compared to higher quality environments. The models illustrate the implications of different degrees and mechanisms of toxicity in response to variability in the quality of the feeding environment, and variability in standard metabolic rate. The models suggest that the relationships between measured degrees of toxic stress, and the maintenance ration required to maintain zero scope-for-growth, may be highly nonlinear. In addition it may be possible to define critical levels of sub-lethal toxic effect above which no environment is of sufficient quality to permit prolonged survival.

Applying systems ecology to the analysis of integrated agriculture-aquaculture farms

The article suggests a preliminary list of properties as a point of departure for quantifying various ecological facets of the integrated agriculture-aquaculture farms.

An ecological characterization of the Stellwagen Bank National Marine Sanctuary Region: oceanographic, biogeographic, and contaminants assessment

The mission of NOAA’s National Marine Sanctuary Program (NMSP) is to serve as the trustee for a system of marine protected areas, to conserve, protect, and enhance their biodiversity, ecological integrity, and cultural legacy while facilitating compatible uses. Since 1972, thirteen National Marine Sanctuaries, representing a wide variety of ocean environments, have been established, each with management goals tuned to their unique diversity. Extending from Cape Ann to Cape Cod across the mouth of Massachusetts Bay, Stellwagen Bank National Marine Sanctuary (NMS) encompasses 2,181 square kilometers of highly productive, diverse, and culturally unique Federal waters. As a result of its varied seafloor topography, oceanographic conditions, and high primary productivity, Stellwagen Bank NMS is utilized by diverse assemblages of seabirds, marine mammals, invertebrates, and fish species, as well as containing a number of maritime heritage resources. Furthermore, it is a region of cultural significance, highlighted by the recent discovery of several historic shipwrecks. Officially designated in 1992, Stellwagen Bank became the Nation’s twelfth National Marine Sanctuary in order to protect these and other unique biological, geological, oceanographic, and cultural features of the region. The Stellwagen Bank NMS is in the midst of its first management plan review since designation. The management plan review process, required by law, is designed to evaluate, enhance, and guide the development of future research efforts, education and outreach, and the management approaches used by Sanctuaries. Given the ecological and physical complexity of Stellwagen Bank NMS, burgeoning anthropogenic impacts to the region, and competing human and biological uses, the review process was challenged to assimilate and analyze the wealth of existing scientific knowledge in a framework which could enhance management decision-making. Unquestionably, the Gulf of Maine, Massachusetts Bay, and Stellwagen Bank-proper are extremely well studied systems, and in many regards, the scientific information available greatly exceeds that which is available for other Sanctuaries. However, the propensity of scientific information reinforces the need to utilize a comprehensive analytical approach to synthesize and explore linkages between disparate information on physical, biological, and chemical processes, while identifying topics needing further study. Given this requirement, a partnership was established between NOAA’s National Marine Sanctuary Program (NMSP) and the National Centers for Coastal Ocean Science (NCCOS) so as to leverage existing NOAA technical expertise to assist the Sanctuary in developing additional ecological assessment products which would benefit the management plan review process.

Ecological and economic consequences of hypoxia: Topic 2 Report for the Integrated Assessment on Hypoxia in the Gulf of Mexico

In this report we have attempted to evaluate the ecological and economic consequences of hypoxia in the northern Gulf of Mexico. Although our initial approach was to rely on published accounts, we quickly realized that the body of published literature deahng with hypoxia was limited, and we would have to conduct our own exploratory analysis of existing Gulf data, or rely on published accounts from other systems to infer possible or potential effects of hypoxia. For the economic analysis, we developed a conceptual model of how hypoxia-related impacts could affect fisheries. Our model included both supply and demand components. The supply model had two components: (1) a physical production function for fish or shrimp, and (2) the cost of fishing. If hypoxia causes the cost of a unit of fishing effort to change, then this will result in a shift in supply. The demand model considered how hypoxia might affect the quality of landed fish or shrimp. In particular, the market value per pound is lower for small shrimp than for large shrimp. Given the limitations of the ecological assessment, the shallow continental shelf area affected by hypoxia does show signs of hypoxia-related stress. While current ecological conditions are a response to a variety of stressors, the effects of hypoxia are most obvious in the benthos that experience mortality, elimination of larger long-lived species, and a shifting of productivity to nonhypoxic periods (energy pulsing). What is not known is whether hypoxia leads to higher productivity during productive periods, or simply to a reduction of productivity during oxygen-stressed periods. The economic assessment based on fisheries data, however, failed to detect effects attributable to hypoxia. Overall, fisheries landings statistics for at least the last few decades have been relatively constant. The failure to identify clear hypoxic effects in the fisheries statistics does not necessarily mean that they are absent. There are several possibilities: (1) hypoxic effects are small relative to the overall variability in the data sets evaluated; (2) the data and the power of the analyses are not adequate; and (3) currently there are no hypoxic effects on fisheries. Lack of identified hypoxic effects in available fisheries data does not imply that effects would not occur should conditions worsen. Experience with other hypoxic zones around the globe shows that both ecological and fisheries effects become progressively more severe as hypoxia increases. Several large systems around the globe have suffered serious ecological and economic consequences from seasonal summertime hypoxia; most notable are the Kattegat and Black Sea. The consequences range from localized loss of catch and recruitment failure to complete system-wide loss of fishery species. If experiences in other systems are applicable to the Gulf of Mexico, then in the face of worsening hypoxic conditions, at some point fisheries and other species will decline, perhaps precipitously.

Sustainable livelihood approach of prawn production and marketing systems in Mymensingh, Bangladesh

An investigation was carried out in Phulpur upazila, Mymensingh to examine the current production practices of freshwater giant prawn, Macrobrachium rosenbergii and its marketing systems with sustainable livelihood approach. The livelihoods of a considerable number of rural poor are associated with prawn production in Phulpur upazila. Based on a sample of 50 farmers, about 94% farmers were found to culture prawn with fish in their ponds. Only 4% and 2% farmers were found to culture prawn-fish-dike crops and only prawn respectively. Prawn marketing is almost exclusively a preserve of the private sector where the livelihoods of a large number of people are associated with its distribution and marketing systems. The market chain from producers to consumers passes through a number of intermediaries. About 40% of the produced prawns are exported and the rest 60% are sold to local markets. The price of prawn depends on quality, size and weight. The average farm-gate price of prawn varied from Tk. 110 to 160/kg, whereas it's [sic] market price varied from Tk. 150 to 350/kg. Most of the farmers and traders have improved their socio-economic conditions through prawn farming and marketing activities. However, concerns arise about the long-term sustainability of prawn farming and marketing systems due to lack of technical knowledge of prawn farming, poor road and transport facilities, higher transport cost, poor supply of ice, lack of cash and credit facilities. It is therefore essential to provide institutional and organizational support and credit facilities for sustainable prawn production and marketing systems.

Ecological limits of high-density milkfish farming

In the Philippines at present, milkfish farming in ponds includes a wide range of intensities, systems and practices. To make aquaculture possible, ecosystems are used as sources of energy and resources and as sinks for wastes. The growth of aquaculture is limited by the life-support functions of the ecosystem, and sustainability depends on matching the farming techniques with the processes and functions of the ecosystems, for example, by recycling some degraded resources. The fish farm has many interactions with the external environment. Serious environmental problems may be avoided if high-intensity farms are properly planned in the first place, at the farm level and at the level of the coastal zone where it can be integrated with other uses by other sectors. It is believed that the key to immediate success in the mass production of milkfish for local consumption and for export of value-added forms may be in semi-intensive farming at target yields of 3 tons per ha per year, double the current national average. Intensive milkfish farming will be limited by environmental, resource and market constraints. Integrated intensive farming systems are the appropriate long-term response to the triple needs of the next century: more food, more income, and more jobs for more people, all from less land, less resources, and less non-renewable energy.

Rapid assessment of the fish biodiversity of the Mburo-Nakivali wetland systems and Opeta-Bisina wetland systems, Uganda

There are 46 different fish species in the Lake Kyoga basin with some of them endemic. The Nile Perch (Lates niloticus) was introduced into the main Lake Kyoga, Nakuwa and Bisina in the late 1950s to increase the fish production. The Nile Perch profileration in lakes Kyoga and Nakuwa led to the almost complete elimination of many native fish species such as Orechromis esculentus and variabilis, Mormyrus kanumme, Schilbe mystus and several Haplochromines species. Lakes Mburo, Kachera, Nakivali and Kijjanebalora are part of the complex system of lakes separated from Lake Victoria by extended swamps known as the Koki lakes, some of the satellite lakes in the Lake Victoria basin. The fisheries of these lakes are important as they contribute to government efforts of increasing food security, poverty reduction and conservation of natural resource base. These lakes are important biodiversity areas because some of these lakes have been found to contain the native tilapiine Oreochromis esculentus (Ngege), absent or threatened with extinction in the main Lakes Victoria and Kyoga. It’s also important to note that this species is only unique to the Victoria and Kyoga lake basins (Graham, 1929, Worthington, 1929). The values of some of these lake fisheries are however, threatened by human activities such as over exploitation, introduction of exotics especially water hyacinth that is already present in River Rwizi and habitat degradation among others.

Water quality assessments in the Opeta-Bisina wetland systems and Mburo-Nakivale wetland systems

It is located in eastern Uganda, the wetland system is characterized by open water that is clear with some emergent vegetation mainly of sedges and floating vegetation dominated by the day water lily Nymphaea sp and submerged water weeds. Some patches of Cyperus papyrus exist in areas with minimal agricultural encroachment. The main inflow into the Opeta system is through River Sironko.

Aquatic weeds hotspots in the Lake Victoria basin Uganda and on Lake Kyoga: implications for their management

Proliferation of invasive aquatic weeds has developed into a major ecological and socio economic issue for many regions of the world. As a consequence, inference on where to target control and other management efforts is critical in the management of aquatic weeds (Ibáñez et al., 2009). Notwithstanding, aquatic systems in Uganda in general and in the basins of Lakes Victoria and Kyoga in particular, have fallen victims to aquatic weeds invasion and subsequent infestation. If these aquatic weeds infestations are to be minimized and their impacts mitigated, management decisions ought to be based on up-to-date data and information in relation to location of infestation hotspots. Aquatic systems in the basins of the two production systems are important sources of livelihoods especially from fish production and trade yet they are prone to infestation by aquatic weeds. Thus, the invasion and subsequent infestation of aquatic ecosystems by aquatic weeds pose a major conservation threat to various aquatic resources (Catford et al., 2011; Kayanja, 2002). This paper examines the extent to which aquatic weeds have infested aquatic ecosystems in the basins of Lakes Victoria and Kyoga. The information is expected to guide management of major aquatic weeds through rational allocation of the scarce resources by targeting hotspots.