Fishery Managementby Jonathan Boulton The Flyfishing industry is becoming very competitive, its inevitable I guess, as the fastest growing participant sport in the country there are a lot of people looking for a perfect piece of water on which to cast that perfect line. Supply and demand kicks in and that means two things, some are going to make money, while others aren't. The classifieds in the local publications are migraine material when it comes to choosing a weekend getaway or where to buy the equipment you are going to need.. And its all out there on offer, farmer Giles chucked a barrel of moth eaten stockies he got from his brother in law Frik, into his muddy farm dam, fixed up his laborers cottage and is marketing a superb flyfishing experience! Some are very lucky, they have chosen to play recluse up in the mountains somewhere and found themselves situated on some pristine water. They can afford to be eccentric, somewhat abrasive, and find that the low rod pressures on their expansive waters result in some excellent flyfishing, hell they might even take the credit themselves! Others who have chosen to make their living from the fly game rely on hard work and perseverance to produce consistent quality fishing on heavily fished waters, if they are going to make the car payments and feed the Labrador. I think it is important to see just how intensively a fishery can be developed and managed, and to do this we should look at the fishery management in Europe and the States so as to realise just how much we still have to learn in South Africa. A recent sabbatical to Montana, Utah and Wyoming proved very enlightening. There are apparently 35 million flyfisherman in the States and when they concentrate on the countries top rivers such as the Green, Snake and The Fork, you can imagine the rod pressures; suddenly your syndicate waters on a Saturday morning don’t look so hectic! I had heard the term the 'Aluminum hatch' before, but it was only when I drift boat fished the Green that I realised exactly what it meant. You would have to stop casting sometimes as a flotilla of fishing and pleasure craft would swarm past, incredibly so, the fish are conditioned to it, and as soon as they had passed they would commence rising for naturals. These waters obviously need serious management, and previously, massive budgets were spent on huge hatchery facilities and stocking, by the local State Game and Fisheries Departments. This form of management along with stream channelization to prevent flooding turned some of the countries best wild fish rivers into degenerated 'put and take' fisheries such as the renowned Battenkill in up state Vermont. Now things are changing and funds such as the 20 million Dollars allocated to the Utah Game and Fisheries Department are now spent on habitat enhancement of the Provo River for instance. This, as well as strict catch restrictions such as the permitted removal of smaller fish but the compulsory return of larger, mature breeding stock leads an increase in wild fish populations, with densities as high as 12000 fish per mile. On a microcosmic scale I think we can learn a lot from this. Surely we should strive to rehabilitate degraded rivers and enhance the habitat so that the fish reproduce resulting in a self-sustaining population of, although smaller, but better quality angling fish. For years landowners in the trout producing parts of this country have seen streams and said 'brilliant - weir it up'. Whether the old fashioned concrete and stone weirs or the slightly better looking loose stone and bidum structures, the results are essentially the same. The water backs up, slows and deposits any material it might be carrying creating essentially stillwater fishing in a series of biologically barren ponds. Aquatic insect life needs flowing, well-oxygenated water gurgling through stones to complete their life cycle. Lift any stone in a healthy unadulterated stream and look at the mayfly nymphs scurrying for safety, they aren't going to be there if those same rocks are submerged. In addition, a barrier such as those mentioned obviously prevents any movement, necessary for fish searching for suitable spawning habitat (once more shallow water flowing quickly, over clean, silt free gravel). South African rivers are high-energy systems, in other words with a downpour of heavy rain a tranquil trout stream looks like the Zambezi River in January. This means that it is not as easy as getting some overseas literature on trout habitat enhancement and thinking you can apply them to our rivers, because you can't. Most of the case studies sited on the internet or in books are the chalkstreams of Britain or the Spring Creeks of the US, these receive a consistent flow of aquifer water and their levels fluctuate very little. Try and place cover points in our rivers and most will be left high and dry in the winter. Bank protection using wooden stake revetment or log current deflectors will be ripped out and deposited on some beach in Mozambique by the end of a rainy summer. Undoubtedly, these basic principles of habitat enhancement are useful but we have to pick and chose them carefully and adapt them to our conditions. A major problem is lack of water in the winter months, a critical period when predation can take heavy tolls, and mature fish are hopefully going to pair off and spawn. It is therefore important to try and make the most of the low water by concentrating and speeding up flows; constricting the channel using current deflectors of various shape and form accomplishes just this. Size and materials should be carefully considered, as should local water affairs legislation because, although improving habitat and encouraging the movement of both trout and indigenous fish, structure placed into a stream can need approval in triplicate! Cover for fish is important, structure provides protection from predators as well a position from which to efficiently hold and intercept food. Many of our highland watersheds are infested with the despised Wattle, and if clearing programs are underway on the banks (which they certainly should be), young felled trees can be strategically felled and secured, so as to provide cover and deflect erosive currents from an eroded or unstable bank. As the wood decomposes it provides detritus upon which the valuable aquatic invertebrates feed on. Always remember that there are implications when places anything into a stream. The basic principles of hydrodynamics will always apply, when protecting the outside of a bend the erosive force of the current will be deflected at right angles and may upset the balance further downstream. Before any habitat work can be considered it is vital that if cattle graze the banks their effect is carefully considered. Especially in the drier months it is inevitable that there will be heavy grazing of the lush bankside vegetation. Loss or damage of this valuable vegetative cover results in destabilisation of the banks, collapse and gradual widening of the channel. Flow velocities decrease, deposition occurs and ideal trout habitat is lost forever. Cattle prefer crossing on shallow, gravelly riffles. I have witnessed on two stretches of river that I mange, a pair of fish at work on a spawning redd on such a riffle, only to find the bank collapsed, the gravel muddied up an the fish long gone after forty cattle were driven across the river since my previous visit. To put this into perspective, in Britain and the States river rehabilitation work is not permitted until cattle have been removed from the banks. The striking effectiveness of this can be seen on the banks of the Chalkstreams in Southern England. One can walk a stretch of river owned by a farmer who has no vested interest in fishing. His stretch of river will be wide, shallow and featureless. The very neighboring property, with cattle fences running both banks will have stable banks fast flowing pool and riffle systems, thick with aquatic insects and free rising browns! If removal of the cattle is not an option I observed a very effective compromise on Milesnick Ranch in Montana. Owner Tom and Mary Kay Milesnick are not keen anglers, but saw huge potential in the degraded spring creek which meandered through their family ranch. Ingeniously Tom used earth-moving equipment in the low water periods when frost bound the moisture and the soil. He removed silt from the pools, sculpted the banks and used the silt to constrict the channel by creating new point bars. He then hand seeded the new sites with three types of rhizomenous grass, which soon stabilized the new areas. Cattle where kept from the banks using an inexpensive single strand electric wire. The cattle where then allowed in on a carefully monitored cyclical basis. Resting the grass for around 30 days, effectively cropping the grass for his anglers, allowing his cattle controlled access to nutritious vegetation while maintaining bank stability. Another impressive development, I noted, was the construction of gravel cattle crossings and watering sites. When grazing on the banks these sites encouraged the cattle to drink and cross on them exclusively as they felt happier on the stable gravel as opposed to muddy banks, thus eliminating any damage while they were in grazing the banks. Many of our stillwaters in South Africa are wetland fed dams, many are also built on rivers and streams, this has enormous consequence regarding the size of fish these waters can produce. One of the greatest limiting factors on trophy fish locally, is their inability to shed their ripe eggs each season, thus becoming egg bound and eventually dying on waters which are not fed by running water in the winter months. On my trophy water Jurassic pond, I have worked on the feeder stream for two seasons now. I have placed a sequence of stone current deflectors, which constrict the flow, even in the lowest water conditions. This assists the fish when their spawning urge pulls them out of the lake and upstream. I have never found it necessary to add gravel as the newly concentrated flow meandering within the current deflectors cleans and removes sit, exposing the clean gravel beneath. I let the grass grow through out the summer so that it virtually seals off the stream. I then fence or put signs up so as to keep anglers off in the winter. I have been lucky enough to have natural reproduction for several years running with varying degrees of success. However the most important thing is that my large mature hen fish get to drop their eggs and even if they are devoured by the platannas, she will have another season of growth. So with just a spot of TLC Jurassic Pond has that unusual, yet very appealing ability to produce a voracious little wild fish that will throw itself at your dry fly and the next minute a subtle take on your nymph that results in 4.8kgs of pristine conditioned hen fish! Taken from |
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