Life History of a Fish: Nile Perch

by Scotty Kyle

I am a Nile perch, not to be mistaken for my miserable little European cousin that’s found in canals and ponds in England, or one of the other small fish given my name by uninformed humans. I am Lates niloticus, the true Nile perch of northern Africa. Given a chance I will probably grow to over two meters – that’s six feet seven inches – and could attain a mass of over 200 kilograms, a massive 440 lbs. Scientists and recreational fishermen call me the Nile perch or goliath perch, but locals call me “king of the river” in some local dialects. The Hausas call me “giwan ruwa” meaning “water elephant” and all hold me in great awe and wonder, tinged with a little bit of fear and respect – particularly when their children are swimming in the water. I have been known to eat crocodiles, mostly small ones, snakes and unwary waterbirds.

I can be various colours, depending on water clarity and other factors, but I am usually darker above, often brown or greenish, graduating to a silver belly below. I have large, shiny scales all over my body and massive pectoral fins with a very large tail fin. My mouth, situated below the front of my head, is very big and wide and, while my teeth may be small, they are many and can be deadly and dangerous. They are arranged in patches on both jaws plus inside the mouth and gently curve backwards which means that, if I bite or simply engulf something, it will have great difficulty getting back out. As it wriggles it inexorably moves itself progressively down my throat.

It is a little embarrassing, but reports of us reaching three meters, that’s over nine feet and half a ton, that’s 500 kilograms or 1 102 lbs., are probably exaggerations. The reality is that most Nile perch are caught in remote African areas by rural people for food and measuring and weighing us is not important to them. “Sport” angling is still very limited and the best estimates available to man suggest that, as I said before, we currently “top out” at about 2 meters. There probably were much larger fish in past decades and centuries, but fishing pressure everywhere is growing and our average size is, thus, generally decreasing. 

Being top predators, we tend to eat almost anything we come across and simply spit it out if it is too big or unsuitable. As a rule, we eat mostly small insects and invertebrates and even plankton, when very small, but we grow quite rapidly and soon only large prey items including fish, mammals, birds and reptiles, can supply the amount of food that we require. We reach about 30 centimeters, that’s about 9 inches, by the end of our first year and are mature by about three years old – with boys growing faster than the ladies and also maturing earlier. Our largest ladies, despite still being generally smaller than males, can produce over 9 000 000 eggs per spawning. That is a lot of eggs and a lot of babies. 

While our breeding capacity is very good for us and our survival as a species, it causes massive problems when we are introduced to new areas. If a human “googles” my kind they will quickly learn of the troubles we have caused in places such as Lake Victoria and Lake Malawi in Africa and in parts of Australia. We can have a devastating impact on indigenous fish species and ecosystems where we can simply eat much of the fish biomass, cause local fish species to become extinct and outbreed other fish species. It is not our fault, it is the fault of the people who went to great lengths to move us around, usually hoping to boost their fisheries, to eat us.

We were taken to Lake Victoria in central Africa in the 1950’s and, as many small species had developed and thrived without large predators, we thrived on them. Even worse, after the disaster in Lake Victoria some well-intentioned, but extremely silly and unthinking, people later put us into Lake Malawi. These unfortunate introductions are now being used as examples of the worst case scenarios that can occur when alien fish are brought into new ecosystems. One human authority, the “World Conservation Union”, places us among the “world’s 100 most invasive species”. We are not “bad” we are just extremely efficient at surviving. 

While I am distantly related to the European perch and similar species (they are placed in the same order: Perciformes), my family is the Latidae and our closest relatives are in the Centropomidae family that contains the barramundi in Australia and snooks in USA. Whatever, I am by far the largest, most impressive and important member of my clan and, wherever I am, I am the top predator and dominate the ecosystem.

Two anglers and a Nile perch
A large Nile perch caught on a fly at night in Cameroon. Image credit: Ewan Kyle.

My family has been a favourite target of fishermen since well before Biblical times. Ancient Egyptian Pharoahs feasted on my species while we were also a staple protein to the “common people” at that time. Because of our rapid growth and ability to survive we were one of the first fish species “farmed” and have sustained enormous and ever increasing and more efficient fishing pressure for over 3 000 years in some areas. Africa, with its often extremely fast-growing population, is always on the look out for new food sources and this has driven our being spread to new areas. Food essentials simply make any other considerations inconsequential and so actions like our recent introduction to Lake Malawi are undertaken despite the known risks involved. In Lakes Victoria and Malawi, although the total amount of fish “produced” may have risen slightly, instead of thousands of small boats catching many small fish, there are now only hundreds of larger boats targeting us. This creates unemployment, confusion and conflict in some desperately poor areas. 

In areas like the Congo River within our natural distribution, we are usually in balance with our fellow ecosystem inhabitants as well as the fishery pressures. In spite of the dense human population who live beside the river and are heavily dependent on fishing to survive, most fish and other species are still present although the fish stocks may be reduced and species compositions distorted. Sadly, the introduction of cheap gill-netting has transformed many fisheries, upset balances and often resulted in greatly reduced numbers of large fish. So, in many areas where we are found there is little real scope for “sport” fishing for “trophy” specimens of Nile perch. 

“Sport fishing” for my species is divided into two main types. The first, and most common, seeks areas where, by some rod and line method, fairly large sized members of my species may be found and caught. There are many suitable destinations where this is being carried out efficiently, safely, fairly easily and cost-effectively. Destinations include large natural water bodies such as Lake Victoria, Lake Chad and Lake Malawi, artificial impoundments (dams) like Lake Nasser and some of the larger rivers of the region including the Nile, Congo, Niger and Volta. Access to these areas is sometimes fairly easy and safe, and well-developed tourist industry exists in countries like Kenya and Tanzania, but local knowledge is essential to get to where fishers can catch us on rod and line. Elsewhere, there might be a “conflict zone” or where fishing rights are fiercely guarded and defended and so simply going to a good sounding area and setting up your rod on a riverbank is unwise. Once again, it is best to check “on line” for a destination and then use a recognized operator to guide your fishing holiday plans. 

One of the best known destinations for catching my species is Lake Nasser in Egypt. There are several reputable operators and charters who can pick people up from airports, take them to the lake, provide or advise on suitable tackle/bait, have appropriate boats and can take them onto the water. They can also advise on fishing approaches and areas depending on whether anglers want simply to “catch a Nile perch” or two, or to “catch a monster Nile perch”. Most of the fishing on Lake Nasser is boat-based and usually consists of trolling with artificial or natural baits. Bank fishing is also sometimes possible, but the lake is vast and we are not evenly distributed.  

Nile perch are found in many regions and, if the aim is just to catch our species, then a casual approach can succeed but, if “good sized” fish are sought, then professional local or international assistance is required. They will help you to find the places where there still are large fish and it is possible and safe to fish. Many anglers would love to catch us on the fly but this is rarely possible as most of the water bodies, particularly the rivers, are large and often very muddy. Apart from clear water lakes such as Lake Malawi, it is usually necessary to fish in the local dry season and this varies markedly from season to season and also often from day to day. 

This has led to the development in the last few years of the second type of Nile perch sport fishing. Several international fishing outfits have spent considerable time and effort seeking out “near pristine” populations of Nile perch in areas where it is safe to camp and fish. Some, in places like the Congo River, target Nile perch on heavy spinning tackle as the water is almost always very high and muddy. Other operators have located places and identified times when water is clear and large members of our family still persist. As the larger lakes and rivers are mostly under heavy fishing pressure, these circumstances only persist in small, isolated areas and often only for short window periods.   

A few angling charter companies have now made available, to the well-resourced sport angler, opportunities to fly fish for giant Nile perch in remote, natural, safe destinations. Most of these are currently in medium sized rivers and, at present, Cameroon is a top destination. The challenge is that the rivers are usually high and muddy and rains are unpredictable. A solution was to identify a short period annually when conditions should be good for fishing. Not only this but, as three species of tiger fish can also be present – and they are voracious feeders – it is only after dark that there is a good chance of hooking a large one of us as tiger fish rarely feed after dusk. So, the really keen, specialist fly anglers can only fish for a short period annually and, as some light is needed, they can only fish during full moon periods. If they do hook one of my larger colleagues, then the fight of a lifetime will ensue and can result in a photograph of a magnificent “trophy” Nile perch followed by its mandatory careful release.

So, while we are not one of the best-known fish species, we “tick several important boxes” and few would argue that we are not an intriguing, potentially spectacular and elusive, opponent. We will continue to play an important role as a source of ever more important protein in some of the most undeveloped and under-resourced areas of Africa. There may also be an increasing role for us in fish-farming but, introducing us to new areas, is not a good idea! It is also very likely that, as time goes on, we will rise quickly in the ranks of the priority targets of sport anglers as information on, and access to us improves. We really are an impressive and unforgettable fish and the capture of a prime specimen will be a lifetime achievement for an angler. 

Main image credit: Daiju Azuma, WikiCommons.

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