February 17, 2006
After seeing the documentary Darwin's Nightmare currently out in LA (Feb 2006), I googled 'nile perch' and downloaded the main column here (first half). I cannot strongly enough recommend seeing the film if at all possible -
waiting for the DVD if necessary and ever comes out -complete story and photos
NILE PERCH - marketing success or ecological disaster?
(This article first appeared in Seafood International, May 1997. The author wishes to thank the publishers for permission to reproduce the material here. Megapesca also acknowledges Centre for Development of Industry for permission to reproduce the
Introduction: Lake Victoria and the Nile perch fishery
The Nile perch Lates niloticus is a large freshwater fish found extensively in the rivers and lakes of Africa. Also known as capitaine, mputa or sangara, it can grow up to 200 kg and two metres in length. It is a predator, and lives and feeds throughout
the water column. Its main attractions as a food fish are its abundance, ease of catching with a variety of artisanal and industrial techniques, its large size and very palatable bone-free white flesh.
Nile perch landing site near Kisumu, KenyaA substantial fishery based on Lake Victoria supplies export markets worth an estimated US$140 million to the three bordering countries - Tanzania, Kenya and Uganda, providing a major source of
revenue for fisherfolk, processors and exporters.
Lake Victoria is the second largest freshwater lake in the World, with an area of 68,000km2. However, the lake is relatively shallow, with a maximum depth of 84m and mean depth of just 40m. The area of the lake is divided into the
national waters of the bordering countries, with Kenya owning 6%, Uganda 45% and Tanzania 49% of the area.
Nile perch first appeared in Lake Victoria in the late 1950s, when it may have have been introduced deliberately. The ecology of the Lake has been significantly affected by this action. By 1980 catches started to increase substantially
to the present level estimated at 500,000 tonnes per annum.
Most of the fishing in the three countries is undertaken from small canoes, using either paddle or outboard power. Typically fishermen will use will use drift nets, set overnight, although some fish is also caught with baited longlines.
In Uganda, industrial fishing techniques are banned, but in Kenyan and Tanzanian waters there is some limited use of pair trawling from industrial scale vessels.
Catch recording is difficult given the disperse nature of the fishery and landings. Official statistics (without doubt under-recorded) from the three countries suggest a production of around 363,000 tonnes in 1994, with 29% landed in
Kenya, 27% in Uganda and 44% in Tanzania.
The fish are landed at numerous small landing sites on the shore or off-lying islands, where they are bought by traders or directly by processors for onward road transport to the factory or market. Only the best quality fish are
selected for export processing.
There is only a limited use of ice by fishermen. Most often the fish are iced by the merchant or processor after purchase at the landing site. Conditions at beach landing sites are poor, lacking potable water supply, clean auction areas
and toilets. However, there is a now a trend to improved control of the distribution chain, with some of the main buyers operating collection vessels to receive and ice fish directly on the lake. Along with extension of line fishing, this should result
in a definite improvements in product quality.
Although Kenya owns the smallest part of the lake, the country has been instrumental in developing the processing and export activity, and both Ugandan and Tanzanian fishermen have historically landed their catches in and around Kisumu, which is the
Kenyan centre of the Nile perch industry. Here there are 12 operating factories (although some fish is also processed in Nairobi and even Mombasa). Now however, both Uganda (with 12 factories at Entebbe, Kampala and Jinja) and Tanzania (with 10 factories
around Mwanza) have both developed a processing capability. The processors have formed strong national associations to represent their members.
Uganda is the only country to impose and reasonably enforce official controls on exploitation, and each factory is given an export quota, based on a nominal total supply of 100,000 tonnes from Lake Victoria and about 20,000 tonnes from
other sources (eg.Lake Kyoga to the north of Kampala). Official policy dictates that about 50% of the catch should be available to the domestic market, leaving 60,000 tonnes for export. However, processing capacity is presently estimated at over 73,000
tonnes per annum.
Trimming of nile perch fillets, Mwanza, TanzaniaAt the processing factories, most of which meet standards of design and construction specified in the EU hygiene directive (91/493/EEC), the fish are washed and sorted. They are chilled
and kept in ice until ready for processing (up to one day). The fish are then filleted by hand without gutting, and the fillets then skinned and trimmed. The skinning is usually done by hand as well, although some processors have installed mechanical
The skinning process adopted depends on the market. The Northern European, American and Australian markets require a deep skinned fillet (30% yield), so as to remove completely the layer of subcutaneous fat. All dark flesh and pin-bones
are also removed. Southern European markets (Spain and Greece) prefer a higher yield (35%) fillet, which is not so heavily trimmed (with pin-bone in) and has a lower price. The Israeli market allows for a much higher yield (40%), which leaves a portion
of the skin attached. The Japanese market demands a skin-on scaled fillet (in which case the yield is 42%).
Fillet sizes vary, from 300g to 1500g. Large fillets above 1500g are portioned and are always frozen, since the premium fresh markets do not accept very high oil content. The oil content of the flesh increases with size of fish, and
ranges from 4 up to 20% in fish over 50kg.
Individual fillets and portions are packed in polythene. If the fish is to be frozen it is packed immediately into waxed cartons of 6kg. or 10kg depending on the market and then blast frozen. Some factories have recently installed plate
freezers to achieve a more rapid freezing of fillets. There is some production of headed and gutted fish and steaks, but these form only a small proportion of the total. Frozen fish is transported to Mombasa in refrigerated trucks (including all frozen
fish from Uganda and some from Tanzania), and exports by sea are exclusively by container.
Exports of fresh nile perch have developed over the last five years. As with most fish from tropical waters, if well handled, it has a long shelf-life - up to 27 days on ice. For exports of fresh fillets, the cartons are held in a chill
store until the consignment is ready for despatch, then packed into polystyrene boxes. These are transported to Nairobi or Entebbe in time for late evening flights to Europe. In addition, there are direct charter flights (for example from twice weekly
from Mwanza to EU destinations, carrying 50 tonnes of fish each time)
The cost of air freight to the European market is in the range of US$1.50 to 2.0, which is more than recovered in the premium over frozen fish (where the freight cost is in the region of US$0.50).
Many of the by-products of processing are also utilised. The swim-bladders (maws) are sun-dried and find ready export markets in the Far East. Belly flaps (with their high oil content) and visceral fat can be rendered to produce a high
quality fish oil. In the last five years, a small tanning industry has developed in Uganda and Kenya, producing high quality leather goods from the skins. Fillet frames are sold on the local market, where they are fried and sold for consumption by street
traders. There is also some artisanal processing of Nile perch employing smoke-drying over wood fires to confer a degree of preservation for distribution to interior markets.
complete story and photos