The Mozambique Tilapia, commonly referred to as the Blue Kurper or just the “Blue”, is one of South Africa's most common inland freshwater fish species. It thrives in South African freshwater systems and is widely distributed and I don’t know of any bass water in Southern Africa where this bait fish is not present. The Blue Kurper is a beautiful fish that rarely grows to more than 3 kilograms in South African waters, although the South African record for this fish is 3,64kg and the IGFA World record is 3,11kg, both caught at Loskop Dam, which is widely regarded as one of the best places in South Africa to fish for trophy size Blue Kurper.
They can be found from the northern part of Mozambique all the way to the Bushman's River system in the Eastern Cape. They are scattered all the way down the east coast past Cape Town and into the west coast region and up into Namibia. The Blue Kurper is farmed extensively and many dams, streams, rivers and freshwater lakes serve as a home for this fish species.
The favoured habitat of the Blue Kurper includes standing waters; they thrive and breed profusely in all water types except very fast moving streams and rivers. They can be found in brackish, fresh and salt waters and can tolerate water temperatures from as low as 13° C to about 43°C. They feed on algae and other plant material but large specimens will feed on insects and invertebrates.
Blue Kurper can be easily caught using earthworm, or with a small curly tail grub or a small spinner. Larger specimens are sometimes caught on crankbaits or soft plastic baits intended for bass. On light tackle a big Blue can give you a fantastic fight, and there are many anglers that target them as a species. Catching large Blues on spinners in late summer is sometimes almost better than bass fishing. Most bass fisherman know how a Blue Kurper looks, but have not studied them to understand their behaviour and how we need to fish imitations of them to attract the attentions of trophy bass. This article is aimed at providing a deeper insight into the Blue Kurper as a bass prey fish specie.
The Blue Kurper has a deep, elongated, laterally compressed body and a bluntly pointed snout with a slightly oblique mouth that extends past the outer margins of the eye. Females and non-breeding males normally have a pale grey to washed-out yellow belly with 3 dark spots on their sides. As a bass fodder fish these are the Blue Kurper we want to imitate.
Normal coloration also includes a caudal fin with distinctive stripes, and a dorsal fin with a grey to black margin often suffused with red. Spawning males have enlarged mouths and blue, thickened upper lips and black bodies but are of no real interest to bass due to their size.
The Blue Kurper is like the Red Breast, but slightly more slender than the Vlei. The Vlei and Redbreast have bands while the Blues have the 3 dots, which makes it easy to tell them apart. The front part of the dorsal fin is the most inconvenient to handle because it has spines on it, and for this reason, like with the Red Breast, bass always hit a Blue from the front and swallows it head first. Blue Kurper are schooling fish and in summer you will often see big schools moving into the swallows. They have a strange habit of lying just under the surface with their mouths sticking out. I always thought they do this due to a lack of oxygen, but I have seen them do this in water with a high oxygen level. Whatever the reason is, they are the only kurper specie that does this and makes it easy for us to identify them from a distance. When they school in the shallows and feed on the bottom, they also have the tendency to turn and flash, just like the Three Spot Ghielemientjie. The flash is not as bright but clearly visible on the bottom.
Blue Kurper are omnivorous and feed mainly on algae and phytoplankton, but also take some zooplankton, small insects and their larvae, shrimps, earthworms and aquatic macrophytes. Their food source includes plankton, aquatic invertebrates and decomposing organic matter. They are considered filter feeders because they can literally filter plankton out of the water. This is accomplished by the mucus secreted by the tilapias which traps the plankton. Digestion of the plankton is started by grinding the food between two pharyngeal plates. The pH level of this fish’s stomach is around 2, which bursts the cells of the plankton. Juvenile Blue Kurper are omnivorous and feed largely on detritus. For the bass fisherman this means that in open water the Blue Kurper will feed on the bottom far more than any of the other bait fish species. Another interesting fact is that they seem to like getting into a habit. If conditions remain the same, a school of Blue Kurper will feed in the same areas as the day before, which can make it easy to locate them again the next time you are on the water.
The maximum size of the Blue Kurper tends to vary based on its geographical location, but specimens of over 4kg have been caught in South Africa. The Blue Kurper can live as long as 11 years. It has an average length of around 20cm and can grow to 45cm. For the purposes of using it as a bass prey fish, we would mainly focus on sizes between 10 and 13 cm (4 and 5 inches). In most dams they actively start breeding at around 14 cm and this means that when we imitate them, we are not really going to focus on their spawning behaviour.
Males are usually found in soft- bottomed areas that are ideal for nest construction, while females and immature fish tend to remain in areas with harder bottoms and more food. This is important as we want to imitate the juveniles that will relate to hard bottom areas. Schools of juvenile Blues can often be seen on concrete slipways and jetties where they feed on the bottom. A very good example of this is the sunken jetty at Hartbeespoort Dam. When the water is high enough to cover the jetty by a few centimetres, schools of juvenile Blues will feed on top of the concrete slabs and bass will be waiting underneath for a Blue to venture off the slab into open water. I specifically remember one afternoon watching a 2 kg bass swim sideways in a few centimetres of water over the slab chasing these Blues. The Blue Kurper does not tolerate temperatures below 10°C. This temperature limits its distributional range. Blue Kurper will migrate to deeper water as cold temperatures set in, but will often move into the shallows on a warm winter’s afternoon to soak up the sun. Bass will often relate to the fist drop off into deeper water from these shallow areas where they wait for the Blues to return to deeper water before the sun sets. Juvenile Blue Kurper form schools where they feed mostly on the bottom but move to the surface on windless, warm afternoons. When this happens we can clearly see the schools moving around as they make small ripples on the water or stick their head and mouth out as previously mentioned.
Blue Kurper are found in depths ranging from 1 - 12m and very often feed on a flat close to a steep drop off to deep water. Whenever you find a shallow flat and a steep drop off you cannot go wrong throwing a Blue Kurper imitation to catch bass. Blue Kurper occur in a widely diverse habitat. They favour shallow bays with a hardish bottom (the juveniles) where plant cover exists. It is perfect if there is a steep drop off close by to deep water. Like the Red Breast they also love to enter newly flooded areas and feed on the vegetation and organisms now covered by the water. Whenever you find a sheltered bay, hard bottom, rocks or any man-made structure, you can be sure their will be Blues around. This is the go to imitation if you fish big bass waters and you see schools of baitfish moving around.
Blue Kurper mature at 14cm in length and can continuously breed in temperatures over 20°C. Spawning occurs when males claim a territory 15-140 cm in diameter and dig a shallow pit for a nest. He then displays in front of the female school convincing a female to follow him back to the nest. The pair will swim in circles before the female first deposits 100-600 eggs onto the nest and then takes them into her mouth. The male responds by releasing his milt, which the female also takes into her mouth to fertilize the eggs. Once this process is complete the male chases that female away and begins displaying for another. The female incubates the eggs in her mouth for 11-12 days at which point she ejects her already free swimming offspring into the water. The young stay with their mother for 4-8 days during which time they can retreat to the safety of her mouth when a predator approaches. At the end of this period the young form massive schools in shallow water while the female returns to the adult school to find another mate. She can spawn again in 10-30 days. The young can grow as fast as 25-61 mm per month and they usually reach 16-18 cm in 3-5 years. They are extremely successful breeders and make up a large part of a bass’ diet in any water where they occur. The breeding months are mostly from November to March but can be longer in the eastern and northern parts of our country, as well in Zimbabwe and Mozambique. The sizes of baitfish that we try and imitate as a bass prey fish is however not sexually mature yet.
Recent Research Findings
The Blue Kurper is a food source for bass from the time they are born to the time they reach about 15 – 20 cm, depending of course on the size of the bass in the dam. A big bass likes a big meal and a Blue Kurper of over 13 cm is a proper meal. They are often responsible for aggressive bass action as schools of bass feed on schools of Blue Kurper.
The Blue has certain markings (the white, yellow belly, the blue/ grey back and the 3 distinctive spots) that act as a trigger for bass. A bass that sees the combinations of these triggers bouncing on the bottom, or flashing near the surface, or close to vegetation or standing timber, or moving quickly down a drop-off will react aggressively. The trick is to enhance the trigger by enhancing the contrast in your imitation. A definite big bass method is to find schools of Blues around standing timber and brush and fish your imitation with a jerking action through the structure and letting it bounce off the structure. The imitation bouncing of the structure duplicates the Blue’s flash of its trigger points as it takes food off the timber or aggressively scratches parasites off its body. Bass often herd schools of blues into bays where they aggressively feed on them. Action can be hectic under these conditions and aggressive fishing with a jerk – stop - jerk style will yield good results. Fishing a drop off into deep water from a shallow flat is another key area where you want to utilise a Blue imitation. When bass are aggressively feeding, a crankbait displaying the right trigger points worked from the swallows over the drop off will work very well. If the bass are not that aggressive, or the crankbait bite stops, switch to a heavy Texas rigged soft plastic imitation and bounce it down the edge of the drop off and on the bottom in the deeper water.
Fish hard bottom structures, standing timber and brush, man-made structures and drop offs using Blue Kurper imitations. Keep your eyes open, especially on windless afternoons and watch for the tell tale signs of schools of juvenile Blues moving close to the surface. If you find them fish close to the surface and try and find some sort of structure you can bounce the lure off. Please remember that when we are trying to imitate baitfish we have to move the lure as a baitfish will move. A baitfish will stand still and then move with a short darting action, or swim around in a school or quickly take cover. A baitfish makes sudden movements so try and imitate that. A Blue Kurper feeding on the bottom turns its body and displays its sides and dots and stands on its head. When it stops feeding it moves to the next spot and does the same.
Remember – a smaller bass is not very fussy, but if you want to trigger a big bite consistently, do everything you can to put the odds in your favour. Don’t only match the hatch with the bait you choose but also by the way you fish it and where you fish it.