Industrial fishery at sea
In 1963, off the Niger delta, the “Guinean Trawling Survey” had the best catch rates of pink shrimp in the whole of the Gulf of Guinea with a fish trawl (Williams, 1968). In 1964, a Spanish trawler conducted an exploratory fishery for shrimps on Nigeria’s continental shelf with the type of net used in the Gulf of Mexico. The following year, two boats from the Gulf of Mexico operated from Lagos and confirmed the presence of good concentrations of shrimps on the Nigerian continental shelf.
The cruises of the research vessel RV KIARA, owned by the Federal Department of Fisheries, and also the surveys conducted by Nigerian scientists on commercial vessels, confirmed the existence of quantities of shrimps of market value, in particular P. duorarum, P. atlantica and P. longirostris (Bayagbona, 1971), P. duorarum being the most important species. Many inshore trawlers were converted to shrimp trawlers. According to Bayagbona (1976), Nigeria’s shrimp fishery actually started in 1970 with the arrival of specialized shrimp trawlers. In 1974, the following were licensed for the shrimp fishery:
|
2 boats |
(50 - 100 CRT) |
|
30 boats |
(100 - 150 CRT) |
|
6 boats |
(150 - 200 CRT) |
|
Year
|
Catches (tons) |
Average number of boats
|
|
|
Fish |
Shrimp 1/ |
||
|
1970 |
943.2 |
911.8 |
16 |
|
1971 |
1 972.2 |
1 345.0 |
21 |
|
1972 |
1 555.2 |
1 245.1 |
23 |
|
1973 |
2 088.2 |
1 358.8 |
23 |
|
1974 |
2 576.7 |
2 021.5 |
29 |
|
1975 2/ |
- |
2 139.0 |
- |
|
1976 3/ |
- |
2 213.0 |
- |
1/ Mainly P. duorarum (heads-on shrimps)Source: Report of the 3rd session of the CECAF Working Party on Resources Evaluation (CECAF, 1976 (b) except (2) and (3): FAO Yearbook of Fishery Statistics).
2/ and 3/ may include catches of shrimps by non-shrimp trawlers
Costal trawlers also land shrimps caught as an incidental catch. In 1974 these boats, numbering 33, caught 75.6 t of shrimps.
The table below gives the catches per unit effort of the Ivorian fleet on Nigeria’s continental shelf (in kg/h, tails, 250 HP standardized shrimp trawler).
|
|
1971 |
1973 |
|
January |
8.9 |
- |
|
February |
9.6 |
- |
|
March |
7.3 |
- |
|
April |
11.5 |
- |
|
May |
20.4 |
13.6 |
|
June |
13.8 |
16.1 |
|
July |
12.8 |
16.5 |
|
August |
11.5 |
9.0 |
|
September |
12.9 |
11.4 |
|
October |
7.8 |
8.9 |
|
November |
9.8 |
5.7 |
|
December |
8.7 |
13.8 |
An important artisanal shrimp fishery exists in the lagoons. Catches are not known with certainty, but Obakin (1969) estimates 250 t for the Lagos lagoon. According to Bayagbona (1970), the fishing season starts in April and runs through to July.
