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Collecting the Blue Zaire Frontosa
by René Kruter

Cypholtilapia frontosa is one of the most commonly occurring cichlids in Lake Tanganyika. Were it not for their existence in very deep water, this type of fish would be just as simple to catch and export as, for example, Tropheus moori. Catching frontosa at great depths comes with many problems which is difficult, time-consuming and expensive. The biggest problem is decompressing the fish. Most fish have a closed swim bladder that controls the specific gravity of the fish which allows it to remain at certain depths without using up energy. The pressure in the swim bladder is regulated by a gas gland. This gland ensures that the pressure remains stable when the fish swims up or down. If the difference in depth increases to several meters, the gas gland requires relatively more time to do its job. The decompression time between catching and bringing fish to the surface differs among species. For example, shell dwelling cichlids can be brought to the surface within an hour from a depth of 10 meters without a problem. The most difficult species of fish is Neolamprologus furcifer; under stress, it cannot tolerate a single meter of difference in pressure without suffering permanent damage to the swimbladder. After being caught at depths of 15 to 20 meters, frontosas need two to three days to be able to reach the surface without consequence. By remarkable coincidence the most beautiful and thus most desired color variant of C. frontosa, the Blue Zaire, actually lives deeper than the other sorts at 40 meters depth. For this reason it takes 4 to 5 days to bring a Blue Zaire to the surface.

My explanation for the fact that these fish live at such great depths is the absence of human settlements in this region. This became obvious to me in a whole other part of Lake Tanganyika, the Kavalla islands. In this location frontosas occur at very shallow depths. Frontosas are particularly intelligent fish and adapt very quickly according to the local circumstances and availability of food.

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Around the Kavalla islands there is a high frequency of fishing by the locals for kapenta, a sort of anchovy. The boats and nets are cleaned on these islands which causes a great deal of fish waste to end up in the water. The Kavalla frontosa lies there in wait of his daily meal, and has thus come to live at a much more shallow depth. The Zaire frontosas are not as lucky, and must really hunt for their food. They are specialized in hunting in groups and at greater depths. Frontosas have a special ability to perform better than other fish at depths where oxygen is scarcer, giving them an advantage over their prey. Through organized hunting practices, they are able to rapidly exhaust and overcome their prey. The Zaire frontosa lives thus, the most naturally and also possesses the best predatorial characteristics. This is also easy to observe in the aquarium. They are harder to keep together with smaller fish, and much more difficult to get to breed. This is all a result of their being less domesticated than, for example, the Kavalla frontosa.

The high price of the Zaire blue is determined by a series of factors. First and foremost is the fact that a great distance must be covered to reach the closest airport. The fish must be caught twice as deep and are much wilder and thus more vulnerable to stress.

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Moreover the geographic region in which they occur is politically very unstable. Catching and thus diving to depths of 40 meters carries with it much greater risks for the divers and the bottom time is much shorter. For this reason, twice as many people are involved in this effort. When you add all these factors up, it surprises me every time when wild-caught Zaire blue frontosas are available for sale. At one point I calculated what it would cost if a fish such as this were to be caught in Europe under these conditions, including personnel costs, insurance, fuel, and costs of the risk involved, and it worked out to NLG 1700 to 2000 (approx. US $740 to $865 at the current exchange rate) per fish!

Frontosas are caught in the following manner: A team of experienced divers goes to the assigned catching location, and the boat goes to the right spot with the assistance of a depth gauge. Then a bag of fish waste (chum) is thrown overboard to
attract the frontosas.

Water Watercraft Underwater Organism Vehicle

About three hours later, the first dive team is allowed to descend. They then place a 20 x 3 meter net weighed down with lead to the place where they observed the first frontosas. A large cage measuring 1x1x1 meter is placed in this area. The frontosas are then chased into the net and are then caught one by one with a hand net and brought to the cage. The greater the depth at which they must be caught, the shorter the bottom time, and the longer the decompression time for the diver. After several teams have caught fish, the cage is moved upwards to a shallower depth. At this point the fish are closely observed. When one of the fish begins to float, in other words, to continuously swim in a downwards direction in order to maintain a constant depth, then it is determined that maximum ascension has been reached for the day.

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Water Scuba diving Underwater diving Divemaster Underwater
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The next day a new cage is brought to the site and the procedure is repeated. However, at the end of the day the new cage is placed in the location occupied by the old cage, and the old cage is brought up several meters. In this way, the divers can fish several days at the same location, and at the end of the week, the divers return with a certain amount of frontosas, dependent upon their success. The frontosa must remain in roomy tanks at the catching station for at least a week before they may be shipped to Europe or the U.S.

Photos reproduced courtesy of African Diving Ltd.
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