The coast of Tanzania is characterized by a wide diversity of biotopes and species, typical of the tropical Indo-west Pacific oceans, and the peoples living there utilize a variety of its natural resources.
Because of the extent of the diversity and variety, several different examples are used by this study to elucidate the complexity of issues and multiplicity of management responses related to use of coastal and marine resources.
It emerges that coastal management requires an integrated cross-sectoral approach to address the wide array of interrelated issues involved.
The study describes the status of selected resources from the principal biotopes (coral reefs, mangroves, seagrass beds and beaches) as well as fish stocks, and it examines various forms of their utilization. Some special cases of endangered species are also examined.
The study attempts to analyze questions of sustainable use in relation to ecosystem dynamics, socio-economic processes, institutions and policies. The characteristics for what we consider as approaching a state of sustainable use are proposed, and the requirements considered necessary for ensuring sustainability are outlined.
Past experience and the current status of coastal and marine resource uses are summarized through the examples chosen in order to explain the main constraints to the attainment of sustainability.
Cross-cutting issues related to the breakdown of traditional management systems for common property resources in the face of increasing commercialization, privatization, and external interventions appear to pose general problems.
The general experiences of community projects, legislation, and mitigation measures are assessed from the examples we have chosen. We present an array of general lessons learned and key factors affecting sustainable use of coastal and marine resources. Amongst these we emphasize:
•Dialogue and linkage between traditional and scientific knowledge systems.
•Mechanisms for interaction between scientists, managers and decision-makers.
•Continued human and technical capacity building of research institutions.
•Essentiality of addressing land and sea tenure and common property rights.
•Genuine involvement and empowerment of local communities and civil society including community-based organizations (CBOs), and local non-governmental organizations (NGOs).
•Credible and equitable arrangements for benefit-sharing with communities.
•Open availability of information for overall transparency and accountability.
•Integration of socio-economic opportunities into conservation programs.
•Recognition of and respect for local and traditional institutions.
•Openness in collaboration between traditional and government institutions.
•Strengthening of relevant institutions providing entry to decision-making.
•Management agreements between institutions for cross-sectoral co-ordination.
•Long-term and broad-based visions in policy thinking.
•Democratic process of public involvement in policy-making and implementation.
Tanzania has a coastline of over 800km stretching from latitude 4º49’S at the border with Kenya to the border with Mozambique at latitude 10º28’S. The continental shelf is narrow with the 200km contour depth about 4km offshore, except at the Zanzibar and Mafia Channels where the shelf extends for up to 80km.
The large islands include Zanzibar (two islands of Unguja and Pemba) and Mafia, and there are also many smaller islands, islets and reefs along the coast. The area of the shelf to the 200m depth contour for both mainland Tanzania and Zanzibar combined is about 30,000km2.
The resources of the shelf area are predominantly utilized by the artisanal fisher folk. Tanzania is renowned for the attractiveness of its coastal and marine environments, high marine biodiversity and rich marine and coastal resources.
The coastal and marine environments include amongst others: Major estuaries, mangrove forests, coral reefs, sandy beaches, cliffs, seagrass beds and muddy tidal flats. Sandy-muddy flats or rocky reef platforms are found in the intertidal zone, while the sublittoral zone consists of extensive seagrass beds and coral reefs.
Rivers including Pangani, Wami, Ruvu, Rufiji, Matandu, Mbemkuru, Lukuledi and Ruvuma all flow to the Indian Ocean and influence the coastal environment through creation of productive brackish water environments in estuaries; maintenance of deltas, tidal flats and shorelines; and nourishment of mangroves and seagrass beds.
These coastal ecosystems interact with each other and together sustain a tremendous diversity of marine life, which is an important source of sustenance for coastal communities. For instance, a wide range of important and valued species are found, including an estimated 150 species of coral in 13 families, 8,000 species of invertebrates, 1,000 species of fish, 5 species of marine turtles, and many seabirds.
There are five administrative regions situated along the mainland coast: Tanga, Coast, Dar es Salaam, Lindi and Mtwara. These regions are further subdivided into districts. The islands of Unguja and Pemba make up Zanzibar, the other part of the Union of Tanzania. The five coastal regions cover about 15 percent of the country’s total land area and are home to approximately 25 percent of the country’s population.
According to the 1988 census, the estimated population of Tanzania was 23 million and this is projected to have risen to 32 million by the year 2000. Based on a land area of883, 749km2, the average population density for the country is 36 persons/km2, while for Dar es Salaam region the density is 1,745 persons/km2. However, in another coastal region, Lindi, it is only 12 persons/km2.
Economic activity is high in some coastal regions. Over the period of 1980-1994, the five coastal regions contributed about one-third of the national Gross Domestic Product (GDP), with Dar es Salaam leading overall with 20 percent of the GDP. However, Lindi and Coast regions are ranked nationally as the poorest. Signs of environmental degradation, as well as a decline in natural resources and biodiversity, are beginning to become more obvious.
This is evidenced by declining yields of fish, deteriorating conditions of coral reefs, and continuing reduction in the area of mangroves and coastal forests. This degradation is attributed to unsustainable use of coastal resources as well as pressures from the growing coastal population.
There are many development considerations that provide strong justification for improving the management of coastal areas in the region, in particular the dependence of the economies of the country on the functional integrity of the coastal ecosystem. Various management responses have been (or are being) undertaken at different governance levels in the attempt to manage coastal and marine resources sustainably.
These responses include traditional management systems, collaborative management arrangements, and enforcement of policies and laws through regulatory mechanisms.
Despite all these efforts, problems of biodiversity loss, pollution, and habitat destruction and degradation continue to increase. This clearly indicates deficiencies in the existing management frameworks.
This paper highlights these deficiencies based on past experiences and the current status of coastal and marine resource uses, and identifies important factors in the attainment of sustainable use of coastal and marine resources. Successful cases of coastal management are also highlighted.
Description of Coastal Resources.
Traditional coastal settlements are generally situated in relation to the availability of natural resources: Correlations can be seen between the location of coastal villages and their proximity to coral reefs, mangrove forests, seagrass beds and fishing grounds.
Beaches provide suitable working places and landing sites. More recent developments are also located according to resources: Port facilities occupy natural harbors, tourist hotels are sited adjacent to beaches and coral reefs, and aquaculture sites are situated according to their various biophysical requirements, whereas industrial enterprises are more mobile.
Corals occur along shallow, tropical coastlines where the marine waters are clean, clear and warm. The complex topography and the high retention of nutrients by coral communities make coral reefs one of the most productive e Due to the narrowness of the continental shelf of most of Tanzania, coral reefs are typically situated close to land.
Coral reefs are common along much of the Tanzanian coastline, and well-developed barrier reefs occur along most of the ocean-facing eastern coastline of the islands.
There are also extensive coral reefs and coral outcrops on the leeward side of the islands, and these vary in species diversity. There are about 700 species of reef-associated corals world-wide, and 150 species of scleractian corals have been reported from Tanzanian reefs (Hamilton and Brakel 1984).The coral reefs provide a range of resources to the adjacent coastal communities and to society as a whole (Bryceson 1981, Richmond 1998). These resources include:
•Food and shelter for animals such as fish, crabs, lobsters, and clams.
•Calcareous sediments that contribute to the substrate and beach formation.
•Natural barriers that protect shoreline against wave action and storms.
•Net sinks for carbon in the form of calcium carbonate.
•Areas for fish breeding and shelter, which support important fisheries. In terms of the total fisheries catch, virtually all of the demersal fish taken are from coral reefs, and a significant part of the other components of the catch are also taken from coral reef areas. The most important fish families among the coral reef catch include the Lethrinidae, Lutjanidae, Siganidae, Scaridae, Labridae, and Mullidae. The other important components of the coral reef catch include octopus, lobsters, squid, various shells for the curio trade, and sea cucumbers (Jiddawi 1998).
•Cultural importance for coastal people.
•Opportunities for education and research.
•Scenic and spectacular sites for tourism, especially for divers and snorkelers.
•Potential for some corals and associated animals to provide products for pharmaceutical and medical purposes. Coral reefs are currently subject to a wide range of natural and anthropogenic disturbances at different intensities and in varying combinations.
The anthropogenic disturbances include direct physical destruction (due to destructive fishing methods and live coral mining), pollution, and over-exploitation (Bryceson 1978).
Leading natural disturbances include crown-of-thorns starfish outbreaks and coral bleaching; however, it is unclear as to whether or how anthropogenic influences have affected these phenomena (Johnstone et al. 1998).
Over-exploitation of key species (predators and herbivores) is causing a decline in certain species and in conditions for ecological shifts, leading to an abundance of undesirable organisms such as sea urchins and alga ecosystems in the world
Mangrove ecosystems play a key ecological role in the coastal environment. Mangroves are trees that flourish in salty, anaerobic and acidic soils. Mangroves grow in sheltered areas of brackish water, where freshwater mixes with seawater.
These areas include estuaries, lagoons, bays, tidal creeks, and inlets (Semesi 1986).The mangrove forests of mainland Tanzania cover about 115,500ha and those in Zanzibar cover 18,000ha(Unguja Island 6,000 and Pemba Island 12,000ha). There are nine species of mangrove trees in Tanzania, though not all are found in every forest (Semesi 1986, Semesi 1991, Shunula 1998).Mangroves serve many functions: They provide shelter for different species; permanent homes for species such as oysters and crabs; nursery areas especially for fish and prawns (shrimps); breeding grounds for fish; and roosting sites for migratory birds (Macnae 1974, Saenger et al. 1983).
Mangroves are also important in the protection and stabilization of shorelines and riverbanks as well as in the enhancement of coastal water quality (Carlton 1974, Wolanski 1985). Additionally, mangroves export nutrients and organic matter to adjacent ecosystems.
Coastal communities in the region have traditionally exploited these rich products of the mangrove ecosystems, as well as various parts of the mangrove trees themselves. For example, mangroves supply communities’ with wood suitable for house building, firewood, boat building and poles (Semesi 1986).
In recent years, the rate and variety of human influences on the mangroves have increased to the extent that the trees are threatened with destruction in some areas. One of the most pressing issues in the mangrove forests is the loss of sheltered areas due to conversion for commercial purposes.
These purposes include conversion to agricultural lands; clearing of mangroves for rice farms in Rufiji Delta, Tanzania (Semesi 1991); conversion to salt pans (Semesi 1991); conversion to aquaculture ponds (prawn farming) (Semesi 1998); and clearance for urban and industrial development (Semesi 1991).
Other threats include alteration of the hydrological conditions (dams upstream of rivers) (Semesi 1986); pollution through using mangrove forests as rubbish dumps (Shunula1998); and over-exploitation of resources, mainly through clearing of mangroves for fuel and construction purposes (Banyikwa and Semesi 1986).
Fish Stocks Marine fisheries in the coastal Tanzania area are predominantly subsistence and artisanal and are mainly concentrated in shallow waters (less than 30m).
Subsistence and artisanal fisheries catches are mainly comprised of a few species groups, namely parrot fish, rabbitfish, sardines, and mackerels, which together account for over 50% of the total catch. The biodiversity of catches are very high by global standards. The subsistence and artisanal fisheries use traditional as well as modern boats and gear.
The vessels include outrigger dug-out boat (ngalawa), dug-out canoe (mtumbwi) and planked boats (mashua).The gear includes basket fish-trap (dema), stakes tidal fish-trap (uzio), hand-line (mshipi), gill-net (nyavu au jarife), and seine net (juya) (Bryceson 1985).
Fishing plays an important role as a source of protein-rich food and employment. The number of full-time fisher folk operating in Zanzibar is about 2,300 (Lyimo et al. 1997) and there are about 15,000 fisher folk along the coast of Tanzania (Haule and Kiwia 1999).
The per capita consumption of fish is 25-30kg/person. The contribution of fishery to the GDP varies between 2.1-5% in mainland Tanzania and 2.2-10% in Zanzibar, mostly from export of fishery products (Jiddawi and Ngoile 1999).
Tanzania exports marine fishery products are valued at US$7,652,700 from the mainland and US$598,203 from Zanzibar (Jiddawi and Ngoile 1999).These products include prawn, bêche-de-mer, shells, lobster, crabs, squids, octopus, sardines and aquarium fish.
The fishery industry also supports a significant number of individuals working in associated sectors such as boatbuilding and repair, gear repair, and marketing of fishery products.
Different management responses have been (or are being) undertaken in management of coastal and marine resources in Tanzania. These responses include traditional management systems, enforcement of policies and laws through regulatory mechanisms, and collaborative management arrangements.4.1.
Traditional Management System is now becoming acknowledged by authorities and scientists that fisher folk in Tanzania (and in other parts of the world) know much more about the coastal and marine environment than previously realized.
Surprisingly, it has taken a long time for marine scientists and decision-makers to realize the value of this knowledge and more importantly to begin seriously recognizing it, although this was advocated long ago (Bryceson et al. 1982).There has even been a misconception that fisher folk do not plan their activities. Fishing activities are dependent on seasons, weather conditions and lunar/tidal effects.
All these factors make fishing a very risky undertaking. To spread the risk of fishing, a sharing system based on labor and capital inputs as well as on age and experience is widely used in coastal communities (Mesaki and Maghimbi 1995).
This system brings a sense of ownership and responsibility to the different groups benefiting from the sharing. Table 2 highlights examples of traditional knowledge and management systems. These examples clearly indicate that all three levels of traditional knowledge, i.e., knowledge, management systems, and institutions, are in existence. Identified three levels of traditional knowledge:
Local traditional knowledge of resources and environment;
Traditional management systems based on existing knowledge and imposed restrictions on resource utilization; and
Social organization for co-ordination, rule-making and enforcement. Traditional management systems impose both direct and indirect restrictions upon individuals for the benefit of a larger group. As ‘rules of thumb’, four types of restrictions are provided (Gadgil and Berkes 1991):
Total protection of some ecosystems. Chwaka Bay mangroves in Zanzibar have been managed for many years through traditional and government-coordinated management systems. Michamvi villagers claim exclusive rights over mangrove forest use and they have used the mangroves for subsistence only. However, this is being undermined by the fact that the government authorities are issuing permits for commercial exploitation of resources.
Total protection of selected important species. According to Williams and Basha (1997), villagers of Ukongoroni in Chwaka Bay have a traditional closed season for octopus during the months of June to August.
Protection of critical life history stages. In Chwaka Bay, prawn fishing used to be prohibited for two to three months at the time when prawns were hatching (Tobisson et al. 1998).4. Organisation of resource harvests under supervision of local experts or leadership.