AFC#7 Upper Zambezi Discovery | african-fisherman

In 1970 we researchers at Kariba noticed that sardines, introduced from Lake Tanganyika, were surviving passage through the dam wall, either through the gates or turbines. A few years later Dr Jubb and Dale Kenmuir both published observations of fish passing alive through turbines and water pumps.

1989 saw Paul Skelton, Dale Kenmuir and I surprisingly finding weed-loving UZ fishes, the dwarf citharine, copper-striped barb, spot-tail barb, upjaw barb and meshscaled topminnow, all caught by hand-net in the vicinity of Olive Beadle and Msuna camps at the western extremes of the lake. In 1990 I visited the Batoka Gorge below the Falls per kind favour of Operation Raleigh from England and managed to sample the gorge fishes on two separate expeditions. I half-suspected to, and thus was excited to find six UZ species new to the MZ at that time. They were the western bottlenose, hyphen barb, mountain catfish, banded jewel fish, UZ bulldog and ocellated spiny eel. The latter was subsequently found near Chirundu in 2000 and was perhaps overlooked during the ’56 pre-impoundment surveys.

In ’94 Tommy Chatham reported having caught an African pike at the Matetsi/Zambezi junction and this was later followed by others caught in the Deka/Zambezi area and reported in the Zimbabwe Fisherman (as this magazine was known) in ’95 - See side bar for the archive from that issue. In the next decade I identified a UZ Zambezi grunter angled from Olive Beadle camp by a young girl, brought to me by her mother, followed a few months later, by a many-spined climbing perch caught by Brian Macgregor at Msuna camp.

Thus 19 UZ species are known to be in Lake Kariba ,10 of which are known weed-loving species. You can imagine my joy, when Tom Oxden-Willows phoned me on the 21st of June to say he had caught a leopard squeaker in the small flooded bay extending into the trailer parking area behind the front chalets of Olive Beadle camp. When I first examined it the next day I thought it was a different species but after thawing and cleaning I confirmed Tom’s identification. This UZ fish is a beautiful aquarium fish and is now the 20th found below Victoria Falls.

I believe that these fishes are leaking through the Falls by means of the water intake and turbines of the Livingstone power station and that a percentage do survive the drop over the Falls itself, provided they are small fingerlings with a low mass/high surface area ratio. If you look up aerial fish stocking from fixed-wing aircraft in the 50s and waterspouts carrying fishes, on the Internet, you may agree with me.

The survival of UZ fish in Kariba depends on the environmental changes taking place within the riverine stretches and shores of the lake, first mooted many years ago. The weed-beds, to provide food and cover and the many drowned trees in the shallows are very important and I am sure that more UZ fishes are still to be found in suitable areas. Anglers can be very important contributors in this respect and I am appealing to all of you to take an interest in the fishes of your angling areas and report any strange catches to your nearest friendly ichthyologist, plus a frozen or pickled specimen, or photo, if possible.

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Upper Zambezi Discovery

By John Minshull, Environmental Ecologist - Acol Chemical, Bulawayo

The Victoria Falls has always been considered an impassable barrier to fish moving upstream or downstream in the Zambezi River, thus dividing the river fish into two distinct populations and ecosystems known as the Upper (UZ) and Middle (MZ) Zambezi respectively. Some scientists considered that fish might survive the drop but others vehemently denied this possibility as did Rex Jubb, Zimbabwe’s first Ichthyologist, in the 1950’s.

When Lake Kariba was built it was found that the snail–eating UZ green happy was present but scarce in the MZ and proliferating in the dam. By the 70s, the rainbow and pink happy’s were also present. The UZ purpleface largemouth also began to be seen and reports that nembwe (robbies) had been found on Zambian shores reached us, but have never been substantiated in Zimbabwe as yet. It is a possibility that these may have been accidentally introduced when stocking the lake from Chilanga in the 60s.

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African Pike Discovered in Middle Zambezi!

The questionable existence of African pike in the middle Zambezi river has recently been dispelled by the discovery of this species in the Deka region.

Tommy Chatham of Hwange wrote to the Zimbabwe Fisherman confirming the fact. Several bank fishermen in the area were reported to be catching unusual fish on hand lines. The first incident was reported when a fisherman brought in an African pike to Mr Gerry Strickland between Christmas and New Year. We are unable to give any statistics on this fish at present, but Mr Strickland intends submitting his specimen to the Bulawayo Museum for further study. More light was shed on the subject, when a second fish was brought to Mr Ian Russel, by another bank fisherman, Mr Robson Dube on 23 January 1995. According to Mr Dube this fish was caught approximately 2km upstream from Sibankwazi Police Station. Robson was fishing with tiny fillets on a hand line with 35kg line. He hooked the fish between 12 and 15 feet from the bank at about six o’clock in the morning. Once hooked, as Mr Dube explained, the pike “started jumping lots”. When the fish was brought to Ian however, it had already been gutted. Although Robson was unable to give details of the stomach contents, he explained that the eggs (the fish was obviously ready to spawn) and air bags were very similar to that of a tigerfish. Mr Dube’s fish had a gutted weight of 380g and a length of 29.5cm.

The African pike is primarily found in the Okavango delta, Kafue river systems and parts of west Africa and Zaire and until recently was known to occur only above the Victoria Falls in the Zambezi. In the confines of the relatively small Zambezi, the pike, because of its small size, has been forced out of the main stream, into the quiet backwaters by the more predominant tigerfish. These fish are structure orientated and wait in ambush to attack small bream and barbs. Pike travel upstream between January and March to spawn, favouring smaller tributaries and flood plains.

There is a notable absence of this species in the Zambian river system. The pike’s discovery beyond its known parameters is obviously interesting and cause for speculation and debate! Tommy Chataham has quizzed some veteran anglers who have fished the river for twenty years or more, and it seems that these are the first pike to be caught below the Falls.

Tommy Chatham and Sheila Black with the gutted pike caught up-stream from the Sibankwazi police station.

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