Niger Delta Ecosystems: the ERA Handbook/The Human Ecosystems: Sangana in Akassa


  • Location
  • Topography
  • Soils
  • The Natural Ecosystem
  • Natural and Viable Society
  • Modern Society
  • The Economy
  • Social and Political Status


Sangana is located on the West side of the Sand Barrier island of Akassa, and on the East side of the Sangana estuary, about 30 kms West of Brass, (see Map 10.).

The main geographical features to which the people of Sangana relate themselves are the Sangana Estuary, West, and the island between this Estuary and the Nun Estuary, East. They see themselves as the largest community in the Akassa Clan but rather than looking East towards Akassa, they tend to look West across the Sangana Estuary in the area of which there are Sangana settlements and settlements owing allegiance to Sangana.

Studies of Sangana and Akassa also took into account "Brass" Island (including the towns of Twon and Okpoama) between the Brass and St. Nicholas estuaries.

The Sangana people speak the Akassa dialect of the Ijo sub-group of dialects within the Ijoid language group. The Ijoid language has been defined as a separate group within the Niger-Congo family of languages, by way of the Volta-Congo subfamily and Benue-Congo branch (Professor Kay Williamson, Department of Linguistics, University of Port Harcourt). The Akassa dialect is close to the Nembe dialect (also in the Ijo sub-group).


Like all the Niger Delta Sand Barrier Islands, Akassa is the result of the longshore drift of sand along the coastline (which continues as sandbars across the mouths of the estuaries). Sand is thrown up by the Atlantic to form a high beach in front of a lagoon created by streams running from the island. The beach finally rises above the high tide level and stabilises. The result of this continuing process is a low corrugated plain, no more than 1 or 2m above sea level, with sandy ridges running parallel to the coast line, alternating with swamps and occasionally small rivers or even, on the estuarine edges of the islands, tidal creeks. The pattern repeats itself from the coast Northwards to the lower mangrove swamps and creeks further inland.

Akassa is subject to both deposition and erosion, the balance of which determines whether the island (or various parts of it) is in advance or retreat. Deposition is facilitated by sand brought down the tributaries of the Niger River and spread along the coast by the longshore drift. At Akassa the drift is from West to East (a little further West the movement is from West to East as the Northeast current hits the "nose" of the Niger Delta, splitting East and West along the coast). Sand is also distributed back up the Estuaries.

The balance between deposition and erosion is complicated. On the coast, it is determined by the amount of sand being brought down the rivers. In the estuaries, it is also determined by the volume of fresh water being carried by the rivers and by the source of the water. The Nun, for instance carries more water from the upper Niger, and thus more sand, than the Sangana, whose water comes largely from within the Delta.

Thus there has tended to be more erosion pressure on the Southwest end of Akassa ("Sangana Point" on Map 10.) and deposition at the Southeast end forming the spit of Cape Nun. Nonetheless because of the Easterly current, sand brought down the Sangana Estuary has tended to be swept East, counteracting the erosion.

However within the last 50 years the Sangana Estuary has become wider: within this period the local people could shout across the river and an aerial photograph of 1963 shows a Cape Sangana, that is no more.

19.3 SOILS

The sandy Akassa soils are Catenas (see 4.5.5) showing a repetitive pattern from North to South according to the low corrugated topography described above. Typically they graduate from the relatively well-drained top of the sand ridge, through a rising water table, through seasonal swamp, to permanent swamp. However there are variations on this theme: the swamp may be brackish or fresh-water; there may be no permanent swamp; and the soils are older in the North than in the South. In addition there are mangrove soils and coastal strand soils.

The soils on the highest part of the sand ridges are Oxisols (4.5.5), sandy soils, subject to continual leaching because of the high rainfall and therefore dependant upon the rainforest humus for their fertility. But they are younger than the Botem-Tai Oxisols and having a high water table, more shallow with a dark brown, humus and iron rich, subsoil between 0.5 and 1.5m where the leachates have accumulated.

In the troughs between the ridges the soil type depends upon whether or not they are subject to permanent inundation and if they are, if it is by fresh or brackish water. The soils collect material rather than lose it (thus despite forming on sandy deposits they have a higher silt and clay content than the ridge top soils) leaching is absent, being young they have only a single soil horizon, and because they are regularly or temporarily water-logged they are reduced. Thus technically these soils are Inceptisols-Aquepts (4.5.5).

In fresh-water conditions where there is some drainage, there are grey-blue "gley" soils, because of the reduced iron and other ions, with red-brown mottles of oxidised iron.

Mangrove soils occur where the troughs carry tidal creeks, in the brackish-water ecozone in the North of the island and where mangrove trees have colonised the West side of the Nun Estuary which is protected from the prevailing Southwesterly winds and currents. These are acid sulphate soils formed where sulphate in seawater reacts with iron in the soils to form pyrites which when oxidised forms sulphates (Hydrogen sulphate gives the rotten egg smell of mangrove swamps at low tide) and sulphuric acid. These soils are not extensive on Akassa and are described in more detail in the essay on Okoroba-Nembe.

Finally there are the strand soils on the ridge of sand that has most recently been thrown above the high water mark (seen on Brass beach, not on Akassa). These soils are shallow and (to a high water table) free draining with a pioneer humus surface horizon that may be only a few centimetres deep. They are classified as Inceptisols.


The natural ecosystems of Akassa are alluvial tropical rainforests, youthful in relation to the lowland tropical rainforest beyond the Delta. The Sand Barrier Islands are an ecozone in their own right containing three major sub-ecozones: the brackish-water (mangrove) sub-ecozone, the fresh-water forest sub-ecozone, and the coastal strand sub-ecozone; (and the ecotones between them).

The biodiversity of the Akassa natural ecosystem is lower than the natural ecosystems beyond them and in some parts of the Niger Delta, not only because of its relative youth, but also because of the limitations on plant diversity caused by the high water tables. Low plant diversity limits associated terrestrial animal diversity (arthropods and the lower orders), however, surrounded by tropical waters, both fresh and saline, of high biological productivity, the aquatic biodiversity is high

The ecosystem of Akassa is no longer natural and to understand the natural ecosystem of a Sand Barrier Island we must take an imaginary walk two or three thousand years ago, starting on the beach and walking towards the mangrove swamps. We walk up the beach, over a newly forming sand ridge (like the one at Okpoama on Brass Island but without the casuarina trees) with patches of the Convolvulus, Ipomea pes-carpea and the shrub, Hibiscus tiliaceus, both with their thick waxy leaves to resist the salty Atlantic winds. Then across a small lagoon formed by a stream trying to find its way to the sea, and to the narrow band of strand vegetation (which may, as at Akassa today, directly confront the beach).

The strand vegetation is low littoral scrub on the sea-side getting taller and more tree-like inland (also with tough waxy leaves tolerant of the salty winds) merging into and forming a protective barrier to the catina alluvial tropical rainforest beyond. Then on through another but better developed swamp so thick with palm trees that it takes us an hour to hack our way through the 10 or 20 metres to where stilt rooted trees become more apparent. This gives way to an area dominated by trees with various roots evolved to breath in soil seasonally inundated or subject to high water tables (buttresses, pegroots and knee-roots) such as Mitragyna stipulosa with its knee roots and Alstonia boonei with its fluted base and adventitious surface roots.

Finally at the top of the sand ridge we reach a thin belt of taller trees such as Terminalia superba, Lophira procera (Ironwood), Symphonia globulifera and perhaps Chlorophora excelsa (Iroko). Undergrowth is least here so that we are tempted to turn East or West where the walking is easy.

We move on to swamp forest again and see the pattern repeating itself, but with variations: the further North, the older the forest and therefore the more diverse. In some places the swamps are wide enough and deep enough to form a lake or swamp, and in others a salt-water creek might intrude with mangrove forest. The sand ridge is so wide that there is a substantial forest with a range of high trees, whilst in others it is so narrow that it is barely distinguishable from the neighbouring swamp.

Quite suddenly, after a swamp dominated by raffia palms, we are in mangrove forest which has formed on the brackish waterlogged alluvial deposits, between the high and low tide marks, in the protected lagoon behind the island. This is an ecosystem where alluvium and organic matter caught by the mangrove roots, in addition to the biomass created by the mangrove trees themselves, create their own medium. The dominant mangrove species is the Red Mangrove, Rhizophora racemosa, with its characteristic stilt and aerial roots, growing in such a tangle that none of the trees can grow taller than 10m, substantially below their maximum potential of 40m. Also, where the high tide is at its most shallow, we see the mangrove species Avicennia which does not have stilt roots but throws upon a carpet of breathing peg-roots around its base.

The animals of the natural ecosystem will have included many of the large mammals and reptiles still found in refuges in Southern Nigeria. There will have been a wide range of bird species because of the proximity of the rivers and the sea. Also a profusion of insects, and other arthropods including a wide range of crabs, and molluscs but, mirroring the plants, with a lower species diversity than in the rainforest further North.


We assume that at some very early date, there were humans on the relatively accessible Sand Barrier Islands and like Botem-Tai it was with the advent of viable society in the area, at least 5000 years ago, that the natural ecosystem of Akassa would have begun to be substantially altered: the very accessibility of the Niger Delta estuaries and their abundance of fish would have made them especially attractive to human activity.

Akassa will have been influenced by early groups of people moving through the numerous protected and interlinked creeks and lagoons inland that stretch from the Volta Delta to the Bonny Estuary. Today, Akassa is settled by Ijo people who separated from other Ijo groups about 1000 years ago and moved Westwards from the Brass Estuary, so that Otuo Island (Map 10), in the Sangana Estuary, is the most Westerly point of the Akassa dialect of the Nembe-Ijo language. Settlements favoured the East sides of the estuaries because the West sides have mangrove forest and the Atlantic coast is too windy.

The Sangana and other Akassa people have always been fishermen as opposed to farmers or even hunters. Moreover they would have been involved in fish and salt trade North and into the interior of Africa. This trade will have been extended by their inevitable contact first with European traders from the 15th and 16th centuries onwards, although the Sangana River is too shallow to have been a major trading centre. The impact of the slave trade was felt throughout the region and although there was a small slave loading point at Kongho on the Nun Estuary, the major slave-trading corridors were to the West (Benin and Warri) and the East (the Bonny River).

The palm oil trade, which grew strongly after the middle of the 19th century, had the greatest long-term influence on Akassa and a large part of the population concentrated on the production of palm oil and palm kernel, at first for local traders, and later for the Royal Niger Company (later the United Africa Company - U.A.C.) which established as a major trading centre at Akassa (Bekekiri) towards the end of the century. This lasted until U.A.C. closed in 1960 when production stopped immediately, for lack of a market, and fishing became the primary occupation once more.

The high demand for oil palm products up to 1960 was probably the greatest incentive that the Akassa people had ever had for changing their environment, but this was mitigated by the fact that the palm was growing naturally and because Akassa is not suitable for large-scale plantation agriculture. The present pattern of land-use is less intensive, now that people have returned to fishing, than it was in the 1950s.

As soon as viable people appeared, paths developed and useful canoe and building timber was removed. Settlements of convenience were established on the sandridges, and abandoned (and established again) leaving behind them the plants that humans find useful and which they favour.

Contact with European traders would have brought in exotic seeds from South America, Southeast Asia and India, such as the mango and the breadfruit. As trade developed more timber trees would have been removed to sell for planks, and later, when iron (and then steel) saws became available the Akassa people would have produced the planks themselves. Casuarina trees probably began to appear in the early part of the 20th century (they are native to the South Pacific).

The growth of the palm-oil trade would have seen oil palms beginning to dominate the forest more and more as they were either planted or, more likely, merely favoured. The removal of the taller trees for timber would have further favoured the natural spread of palm trees that are shaded out in the high forest (A process that continues despite the loss of the palm oil market in 1960 because the taller trees continue to be removed). A similar process is apparent in the wetter parts of the swamps where raffia palms are protected and encouraged for palm-wine, much of which is distilled into gin (kai-kai). This tendency of the palm trees to dominate the forest will have favoured animals that are attracted to palm trees, such as certain tree snakes, palm-nut civets, rats, the palm-nut vulture and harrier hawks.

The exploitation of the ecosystem (which included limited hunting, and collection of periwinkles, oysters and crabs from the mangroves) in the interior will have intensified as the population increased. First with the decline of the slave trade and much later with the introduction of modern health services, although settlement has largely remained confined to the estuaries.

The result of the activities of a viable society on Akassa has been to create what can best be described as a cultured forest. That is highly depleted from the forester's point of view but not technically secondary forest since it has never been entirely cleared for farming; reduced somewhat in its biodiversity, but nonetheless remaining a viable ecosystem, able to withstand such shocks as the Texaco oil spill in 1980. Our walk today sees coconut palms in the littoral and strand sub-ecozones, far fewer big trees (and thus more undergrowth, although foot paths would have made the going easier), many more palms, (the palm swamps that would have been more open before 1960 are again hard to get through) and on the sand ridges, a predominance in places of exotic economic trees such as bread-fruit and mango. On the wider sections of the sand ridges (on Brass) we pass unimpressive cassava farms and sandy scrub where farming has been tried and abandoned. The mangroves do not look a lot different although we notice the stilt roots on the creek sides cut back to facilitate canoes and from harvesting oysters; also we see small canals cutting off some of the bends in the rivers.


The Akassa ecosystem remains, for the time being, viable and the Akassa people are not a threat to it. The modern threats are (not necessarily in order of importance) the oil industry, fishing, erosion and population growth.

The oil industry does not affect the Akassa people as much as it does people elsewhere in the Niger Delta. The Texaco oil-spill of 1980 was classed as the worst ever in Africa: it was devastating in the short term but there is no evidence of longterm damage.

The local fishermen of Akassa are not a threat to fish stocks on the area: their technology has barely changed in the last 100 years, although they now sometimes use nylon nets. The threat comes from deep- sea fishing boats that are able, in Nigerian conditions, to ignore national or international standards and legislation. The losers, if stocks do start to decline, will be the local people who have no economic alternative. There is no local hard evidence of a decline, and although some fishermen complained that it was harder to get fish (this may be due to the increased number of fishermen as unemployed Sangana men return from Port Harcourt) and we saw the landing of some very impressive catches.

Erosion of the Akassa coastline is a natural hazard. However, the construction of the Kainji Dam in 1967/68, by reducing flood discharge, has added to the erosion problems down-stream: there is evidence that at Onitcha the Niger River carries 20% less load than it did before the Kainji Dam was built which could tip the scales in favour of erosion along the whole Nigerian coastline. In addition to the Sangana Estuary, there is severe erosion on the Southeast point of the Brass Estuary and on the coastline between the Sangana and Fishtown estuaries.

Human population growth on Akassa is unlikely to be lower than other areas in the Niger Delta. However there appears to be substantial outward migration from the area as young men and increasingly young women go in search for employment, which reduces population pressure locally (but, of course, can only make matters worse in places like Port Harcourt). Twon (Brass) is a good example of a once important town on the Niger Delta coast that has not grown at all and possibly shrunk since 1960, despite the Agip terminal. (The only obvious urban growth, the large shanty town encouraged by Agip employment, was sacked by the local people in October 1993 and the occupants sent home).

Other Sand-Barrier Islands suffer to a greater or lesser extent from the same environmental problems described above. Brass, for instance, has the Agip terminal at Twon that has created pollution, social upheavals and erosion by the construction of a canal, but which has brought electricity to the area, that the people see as a great benefit. Water pollution is a serious problem in the Benin, Forcardos, New Calabar and Bonny Estuaries because of industrial activity.


19.7.1 FISHING

Fishing dominates the life of Sangana and there are six types: deep-sea fishing; in-shore fishing; estuarine fishing; beach fishing; swamp fishing; and mangrove fishing. Much of the fish is dried and sold to Igbo traders who are not allowed to fish; a number of the Sangana women also trade fish.

The deep-sea fishing is primarily undertaken by Ghanaians, who are not allowed to do anything else. This is generally more capital intensive than the fishing of the local people: using large powered dugout canoes or large plank built powered boats with crews of 6 to 8. The larger boats go out for 2 or 3 days at a time, catching Shark, Barracuda, Tuna and other large fish.

Indigenous fishermen fish closer to the shore also using dugout canoes (with sails or manually and mechanically pulled), and plank built boats (much smaller than the Ghanaian boats). Including others, they catch Shiny Nose, two types of Catfish, Barracuda, Tuna, Red Snappers, Rays and Sawfish; and further in shore, Bonga, Mullet and others. Crabs, the Spiny Lobster, and shrimps also come from the inshore waters.

Estuarine fishing tends to be by pulling canoe and the catch is similar to the inshore catch.

Beach fishing is mainly undertaken by young men with throwing nets, catching the smaller fish such as mullet, and includes taking beach crabs. Small boys fish with lines and hooks in the creeks and rivers.

Basket fishing is done in the swamps catching, amongst other fish, Talapia and mangrove fishing includes the collection of periwinkles, oysters and crabs.


Like other Niger Delta communities, although Sangana lies in an oil producing area is gets no benefits from the oil wealth that accrues to Nigeria, but it bears some of the economic costs: the Agip spill in 1980 has had no long-term environment affects, but it has had a strong psychological consequence inasmuch as people constantly fear another spill (this fear was realised by a small spill in February 1993).

Farming is an incidental activity, dominated by fruit trees planted around houses (mangoes, plantains, papaya, and coconuts). There is a little cassava, very small rice plots planted on cleared mangrove soils, and chickens.

Other primary industry comes a long way behind fishing and includes: raffia wine tapping (by visiting Ogonis), oil palm cutting, hunting, and timber felling.

Most secondary industry is related to fishing and includes boat building (dug out canoes and with planks), fish drying and manufacture of nets, baskets and drying racks. Agricultural secondary industry is minor by comparison including palm oil and palmkernel production and gin distilling from raffia palm-wine. Non-agricultural secondary industry includes: tailoring; baking; brick making; basic carpentry; and building. All are dependent partly or wholly on imports


The economic activity of Akassa is entirely dependent upon fishing: all other food is imported. Real incomes are probably above average and unlike many parts of Nigeria, there is no protein shortage. Nonetheless there is a capital shortage and it is difficult for young men to set up as captains of their own boats.

Except for schools, public services are rare: there is no piped water, no electricity and health services are rudimentary. There are no roads.

The society is run by men who make most of the decisions but as fishermen and unlike most rural Nigerian societies, they do not appear to have an easier life than the women who process the fish catches.

There is not the deep frustration, about the lack of facilities, education and opportunity, that is so obvious in many Niger Delta communities, or, despite the Agip spill, anger with the oil industry (although it was a different story in Brass). All the same there are complaints about education, poor drinking water and electricity. As a result of the low level of frustration there is no strong political feeling apart from a pride of independence. There is a high level of self-organisation and discipline, by necessity to some degree, because of the government's apparent ignorance of Akassa and communities like it.