The world’s fishing grounds have leveled off in the last decade with the majority of wild stocks being fully exploited due to an increase in the demand for fish.

Aquaculture production offers great potential in responding to the increased fish demand and has exclusively increased world’s fish production by 20 million tonnes (mt) over the past decade.

By the year 2010, the world fish food is set to increase to about 105 mt and the said increase from the current levels would again have to come from aquaculture.

Fishery Activities

Two main sub-sectors contribute to fish production. They include capture fisheries and aquaculture.

1. Capture Fisheries

Artisanal fisheries constitute the most significant fishery sector in terms of people engaged in or dependent upon it and the very high percentage (66%) in this sector contributes to the country’s fish production. Yet, this sector is the poorest in terms of its standard of living, with the fishermen generally making a subsistence living.

Small-scale fisheries can be categorized into coastal mechanized and canoe fisheries, brackish water/ lagoon subsistence fisheries, and the capture fishery of man-made, natural lakes, rivers, and flood plains. Artisanal and industrial fishing activities are of great importance in our coastal and marine waters.

The artisanal sector consists of small sub-sectors such as lagoon, estuarine, and inshore canoe fisheries, which are characterized by low capital outlay but remain the backbone of fish production.

The industrial sector is characterized by a high capital outlay on vessels, cold storage, advanced technology, and foreign exchange generation as its major attribute.

The brackish water canoe fishery operates from small traditional dug-out canoes of about 6m LOA using gears such as set nets, cast nets, Bonga drift nets, as well as lift and scoop nets, and hooks. The Coastal canoe fishery operates up to and sometimes beyond seven nautical miles of the inshore waters.

2. Aquaculture

Fish farming (Fresh water and mariculture) is presently making a significant contribution as well to the world food fish supply. Aquaculture ranges from simple ponds using naturally occurring food sources to highly intensive systems with water control, aeration, and supplemental feeding.

It could be practiced in many forms including inland fish farming, brackish water systems along the coast, and marine cages and net pens. Farm size can range from thousands of hectares down to the size of a backyard.

The majority of global production comes from freshwater aquaculture (58% in 1999), followed by mariculture (36%) and brackish water (6%). Aquaculture now represents more than 30 % of total food fish production, compared with just 7 % in 1973, and presently now, world food fish production is around 72 million metric tonnes.

However, Nigeria’s aquaculture production at 15,000 tonnes is second in Africa after Egypt with Nigeria and Egypt jointly pulling a total of 84% while the rest of the Africa countries contribute the remaining 16% at an annual growth rate of 3% from 1985-1997. Based on a current per caput fish consumption of about 13.0kg per year approximately a 91million metric tonnes would be required to meet up the food fish demand by year 2010.

In the coming decades, aquaculture will likely be the greatest source of increased fish production towards meeting the challenge of food fish demand in the country and world over. The public and private investment sector would have to play a major role in the area of fish disease, water pollution control, fish seed propagation and fish feed production and nutrition.

Fishery Resources

Economic Importance of Fishes and Fish Farming Business

1. Shrimp Resources

Shrimp resources are abundant in river mouths and lagoon entrances. Among important species are the pink shrimp (Penaeus notalis), the tiger shrimp (P. kerathurus). Parapeneopsis atlantica occurs in abundant quantity in coastal shallow water, 0-20m depth and commands a local economic importance.

The royal shrimp (Parapenaeus longirostris) occurs in deep waters, 60-400m depth but its distribution of abundance with depth varies between 60 and 120m in Nigerian water.

2. Pelagic Fish Resources

The major pelagic resources include the Bonga fish (Ethmalosa fimbricata) Sardinella aurita and Sardinella mandarensis. Others are theanchovy and the horse mackerel. The Bonga is the most valuable and abundant fish in the artisanal fisheries in the country while the sardinella are less abundant but also of economic importance.

The bonga fish occurs along the whole length of tropical West African coastline with concentrations in Sierra Leone to Senegal and Nigeria to Cameroun. Sardinella aurita is considered the most valuable clupeid is the Gulf of Guinea supporting large canoe fishing in Ghana, Sierra Leone and Cote d’Ivoire.

3 Off-Shore Pelagic Resources

This include tuna and other related fish species and perhaps the most commercially important fish species of all fisheries resources in West Africa. The prevalent species include the skipjack (Katsuwonus pelamis), the yellow fin tuna (Thunnus albacares), the big eye tuna (Thunnus obesus) and the frigate tuna (Euthynnus alletteratus).

The skipjack and the yellow fin tuna are the most abundant and constitute about 75% and 18% respectively by weight of pole-and-line catches. Other countries rich in tuna fish resources are Senegal, Sierra Leone, Ghana and Sao Tome and Principe.

4 Fauna Resources of the Equatorial Zone

The resources in the equatorial zone are characterized by their heterogeneity in the size and variety of fish species. Longhurst (1961) classified the dermersal fish resources into three main faunistic groups:

(i) Croaker fauna- This consists of the silver to grey fish including croakers Pseudolithus senegalis, P. typus, P. elongates and P. brachygnathus, the thread fins (Galeoides decadctylus), Pentanemus quinrifilis and Polydactylus quadrifilis and Polydactylus quadrifilis, the Arid catfishes and spade fish (Drepane africana). The croaker fauna live mostly above the thermocline on mud and muddy sand deposits and hardly penetrate the cold watermass of the South Atlantic Central water below the thermocline.

(ii) Snapper fauna- This consists mainly of red fish including the breams (Pagrus spp.), Lutjanus spp., Epinephelus spp. and the gurnards (Trigla spp.). They are found on clean sand with shell and oral above and below the thermocline to a depth of over 100m. However, some species are found to occur above and below the thermoclines which are known as the eurybathic species

Table 1: Distribution into Zones of the Continental Shelf Area (0-200Km²) of the Gulf of Guinea

Coastal Country	Surface of continental shelf (Km²)	Total surface area (Km²)
0-10m	10-50m	50-200m
Senegal	3,600	11,600	8,400	23,600
The Gambia	1,100	2,600	1,400	5,100
Guinea Bissau	16,300	14,000	6,800	37,100
Guinea	5,600	28,700	7,900	42,200
Sierra Leone	5,000	16,200	6,300	27,500
Liberia	1,500	5,300	11,600	18,400
Ivory Coast	–	4,700	7,600	12,300
Ghana	–	11,700	8,500	20,200
Togo	–	1,100	500	1,600
Benin	–	2,100	900	3,000
Nigeria	5,100	21,600	14,300	41,000
Cameroun	3,400	5,700	6,300	15,400
Equitorial Guinea	–	2,000	1,700	3,700

Source: Domain (1980)

(iii) Semi-abysal fauna- This occur between 100m and 400m andconsists of small, red to black fishes such as Antigonia spp., Capros spp., Peristedion spp., Penthereroscion mbizi, Ariomma melanum and a variety of deep sea crabs of Geryon maritae.

The two species of Ariomma found in Nigeria waters are very good raw materials for canning. Off the Nigerian coast, the croaker fauna is the main stay of the industrial inshore demersal fishery with catch rate per unit efforts decreasing with depth.