The Tanganyika sardine, is known as Kapenta in Zambia. The Kapenta fish is really two species (Lake Tanganyika sardine, Limnothrissa miodon and Lake Tanganyika sprat, Stolothrissa tanganicae), both of which are small, planktivorous, pelagic, freshwater fish originating from Lake Tanganyika in Zambia.
This little fish from Lake Tanganyika is usually around 7cm long, its maximum length is 10 cm.
They form the major biomass of pelagic fish in Lake Tanganyika, swimming in large schools in the open lake, feeding on copepods (small crustaceans) and potentially jellyfish. Their major predators are four species of the Lates fish (related to the perch).
The Lake Tanganyika sardine is endemic to Lake Tanganyika extending into the lower reaches of the Malagarasi River. It has been introduced to Lake Kivu in Rwanda and the man-made Lake Kariba in the Zambezi valley between Zambia and Zimbabwe and more recently into the Itezhi-Tezhi Dam in Zambia. It has colonised Cahora Bassa lake in Mozambique from Lake Kariba, the fish have survived transit through the hyro-electric turbines in the Kariba Dam and made their way downstream to colonise Cahora Bassa.
The depth used by Lake Tanganyika sardines is determined by the depth of the thermocline and the amount of dissolved oxygen. Below the thermocline the water is normally anoxic (water with no oxygen) and from November to April the fish are found no deeper than 20 m. Adults migrate into deeper water as they grow larger, with the smaller, young fish preferring clear water of around 1.5 m deep with a rocky or sandy bottom and also occur in areas with steep shores . The adults move into the shallows to breed, this is usually during the rainy season and peaks in May and June and again in December and January but has been recorded throughout the year.
Kapenta is normally caught at night using parrafin pump lamps to attract them into the nets. There is normally one large boat which has a large ring net that closes on the bottom and several light boats that stay out for a few hours first to entice the fish into the area.
Kapenta is usually dried in the sun on a clean surface such as concrete slabs, rocks or netting. Drying on racks gives the best results. Drying takes one day or more, depending on the weather. Unfortunately the kapenta season coincides with the rainy season when the fish congregates and sundrying may not always be possible causing postharvest losses. These losses are mostly economical as the lower quality dried fish fetches a lower price. In the worst case the dried fish is used as chicken feed. Salting before drying is a solution: kapenta is salted at a ratio normally of 2.5 kg per 30 kg of fish, and dried in the hot Tanganyika sun. It is a hugely important staple, providing refrigeration-free protein to people of Africa. A cup of dried kapenta will feed a family.
A recent chemical composition analysis of kapenta by the National Food and Nutrition Commission (NFNC) shows a great variation in the nutrient composition for the dry and fresh fish.
NFNC principal nutritionist Mr Musonda Mofu says dry kapenta contains 209 calories of food energy compared with 85 calories of food energy in fresh Kapenta. In addition, dry Kapenta contains 63 grammes of protein and only 16 grammes in fresh Kapenta.
The nutrition problems of iron deficiency and vitamin A deficiency can also be addressed by consuming kapenta as it has a high content of these minerals.
In general, Kapenta is a healthy food and very rich in protein. It also has low levels of saturated fat and is a rich source for omega 3 and omega 6 fatty acids.
As a result of this chemical composition, Kapenta, like other fish, may reduce the risk of disease including prostate cancer, depending on the frequency of consumption. Kapenta is also rich in Vitamin B12, which is important in the promotion of cardiovascular well being.
Kapenta is key on the menus of many Zambians. It can be used to promote protein consumption especially among the poor.