Feature

Debate on the Trout Controversy

Response from Dr Ian Cowx, UK

The issue that you are dealing with is a very sensitive one indeed. I am fully acquainted with the issues in SA and know many of the arguments from both sides.

From the positive side, introduction of trout has improved the quality of fisheries and brought much need income to rural economies. Fish farms similarly have improve the livelihoods of many. The introduction of trout, I feel can be justified IF the habitat it is introduced is isolated and holds no endemic or endangered species and it can be proven that trout will have no impact. The latter is almost impossible to achieve and I believe the precautionary approach sholud be adopted in ALL cases. It is possible that new man-made environments like reservoirs can be stocked with trout to give a boost to the local economy through tourism etc, and this is often the
justification. However, if the fish can escape up or downstream and potentially harm the ecosystems then the precautionary principle should prevail.

The problem with introduction of trout, and especially rainbow trout in SA, are the harmful effects. It has definitely resulted in a huge impacts on endemic fishes through competition and predation. In Europe the introduction of rainbow trout has been implicated in the reduction of native salmonid populations in Lake Ohrid, Macedonia. There are also many reports of rainbow trout escaping from farms into rivers and decimating the endemic
fish stocks, particularly through predation of the juveniles. Other cases suggest that Oncorhyncus mykiss displaces endemic species through aggressive behaviour and alters the fish community structure. In SA I am aware of the many problems on rivers where trout have been introduced and have resulted in degradation of the endemic species communities. In any society this is not acceptable. Furthermore Agenda 21, and presumably the output of Rio +10 in Cape Town next month, stresses the need to conserve biodiversity. The introduction of trout into a new habitat does not conform to the spirit of this protocol.

Whilst I do believe there is a place for introductions of fish to create new fisheries, this must not be at the expense of biodiversity or environmental degradation. There are a number of guidelines (FAO/EIFAC + ICES) available to aid society in making the correct decision over stocking and introductions but rarely have these been followed. I believe that the guidelines should be followed to the strict letter of the law and we would prevent many of the catastrophes that commonly associated with this practise. Furthermore, the final call on whether the introduction should take place should be made by independent person(s).

Irrespective of the above, in the first place the person proposing the introduction should assess whether there is an endemic or indigenous species that would achieve the same objectives (usually to enhance the fishery). In most cases this is the situation, but cavalier attitudes towards a new and supposedly exciting fish, often prevail.

This whole issue is a hotly debated one across the world and as Chairman of the FAO/EIFAC Working group on Stocking and Introductions I have always take the bottom line that if the introduction is not necessary or justified it should not be sanctioned.

Dr Ian Cowx

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Response from Dr Phil Pister, USA

Thank you for providing this opportunity to comment on the introduction of
alien species, especially trout. Whether or not this is advisable depends upon the viewpoint of the individual involved. Anglers are usually in favor of such things as introductions of game species, unless they are "ecologically aware" of the inevitable negative impacts to the biota into which they have been placed.

Thoughtful biologists, on the other hand, keenly aware of the need to preserve natural biodiversity, will be almost universally opposed to introductions of foreign organisms, because they are aware of the adverse and frequently irreversible impacts of such things. In a career that now spans more than 50 years working as a fishery research and management biologist in California in the U.S., I have never observed an instance in which biological integrity has benefitted in any way from such introductions. Ecosystems harbor no vacuums, and when a foreign organism is introduced into them, something has to "give," and inevitably this is a native organism of some sort, and most often a native fish species.

Most of my career has been spent in trying to eliminate alien fishes from the
habitats of our native fauna here in this part of California. In one instance
an invasion of brown trout came very close to rendering extinct the entire
world population of the California golden trout (Oncorhynchus mykiss
aguabonita), California's state fish. I began this project in 1965, and it is
still in progress. It will take awhile, but we expect to win within the next
few years. There are no easy or quick answers to such problems.

Other instances involve invasions of introduced largemouth black bass
(Micropterus salmoides) into the small springs that harbor small populations of native pupfishes and other small fishes. Having evolved in the absence of
predators, these little fellows are easily eradicated by a much larger and
aggressive predator, fishes that I have come to consider as chainsaws with
fins.

I could go on and on at this point, but it would be repetitious for me to do
so. In summary, humankind's penchant to introduce gamefishes into virtually
everything that is wet throughout the world has constituted a great tragedy, as we have witnessed in Africa's Lake Victoria, where the Nile perch (Lates nilotica), introduced to provide both sport and food, has resulted in the virtual elimination of native Cichlid flocks of great and irreplaceable scientific value. Further, to cook Nile perch and render them palatable, native human populations have virtually eradicated much of the area's vegetation.

Let me end by pointing out a trend we have noted in California and other parts of the U.S. It appears that sport angling is losing its popularity and that it may prove to be a diminishing social phenomenon. In 1965, California sold more angling licenses than it did in 2000, although the human population increased by nearly three times during the same time period. So governmental agencies may actually be supporting a dying activity in their efforts to provide sport angling utilizing alien species. Things may be different in South Africa, but likely not. Sport angling will likely always remain a popular pastime for many, but it indeed seems to be waning, at least in the U.S.

California has a great variety of trout farms, operated by state and federal
agencies and the private sector. Their entire purpose is to provide sport
angling, mainly by the rearing and planting of ranbow trout. This practice
began about 100 years ago, and most of the damage was done before the
scientific community became even minimally aware of the biological injury that was being effected by planting trout into pristine ecosystems. So most of the damage is now well in place and is essentially irreversible, Those few waters that we have (we have about 1,000 waters in this immediate area) that have not been planted with trout are now guarded zealously to keep this from happening. This surely best serves the yet undetermined needs of future generations. We have found that it is very difficult politically to reverse these planting procedures once they have been started. Angling pressure in this area is enormous. Trout are not native here, but they are firmly entrenched.

Dr Edwin Phil Pister

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Response from Roger Bills, South African Institute for Aquatic Biodiversity

Biologically no alien introductions can be beneficial - there are going to be impacts. Trout are predators and if conditions are right can do very well in parts of Southern Africa. Even if they don't do well their numbers can be artificially enhanced every year with stocking programmes.

In many instances the areas where trout enthusiasts wish to develop syndicates or individual trout waters are cool upper catchments. These areas are typically inhabited by few fish (species and numbers) and these often have very poor abilities to cope with predators. The consequences are that often trout eradicate indigenous species - not just fishes either - frogs are probably heavily impacted too although there is probably even less
data for this group than fishes. Most of Lesotho has been reduced to trout waters - only six populations of the Maloti minnow exist and this is mainly due to rainbow trout.

In other regions other species are responsible for similar problems - much of the western cape is dominated by small mouth bass. However, species indigenous to South Africa such as Clarias gariepinus and Sandelia capensis, once moved outside of their natural limits, have had similarly devastating effects.

So - I think it is a bit unfair to simply target trout. It is a bigger problem which needs to be addressed as a whole. Secondly it is not simply a biological problem. Trout and bass is reasonably big business and we aren't about to remove all the oak tree in Grahamstown so I would not advocate removing all trout either. I think what should be done, and it should be spear headed by conservation organisations (WCNC/National Parks), is that areas should be identified as high conservation value and aliens should be removed or not stocked in these. Other areas should be allowed as legitimate trout, bass whatever rivers and managed by angling associations with guidance/collaboration with nature conservation organisations. There should be a lot more positive communication between these groups - slanging matches  do little to move the situation along, in my opinion.

Roger Bills,
South African Institute for Aquatic Biodiversity,
(formerly the JLB Smith Institute of Ichthyology)

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The third issue centres on the entirely un-coincidental relationship between the fact of the presence of trout and the effectual preservation of the stream by way of prudent husbandry of the entire ecology of its fragile catchment.

Giants Cup Wilderness is a case in point - remarkable, not so much in itself, but as a representation of the microcosmic scenario that is repeated, not once, not twice, but endlessly throughout South Africa’s "trout zones". The scenario sees a block of land abutting on, or near to wilderness, high in the catchment. The land is entirely unsuitable for farming, or for any other intensive development. The owners must earn a living and their commercial options are limited. They might subdivide the land and allow each parcel to be mismanaged and exploited according to the whim of each owner. Or they might profitably commit it to forestry, or perhaps develop it as an intensive recreational destination. From an environmental perspective, each and every one of these options would result in rapid and far reaching degradation of the entire catchment. Were it not for the trout, those would be just about the only options.

Instead, by avoiding intensive and unsustainable utilisation of the natural asset at any specific point, in favour of low intensity utilisation across the entire resource base, it has created itself as a viable and successful trout fishery. It is a registered site of Conservation Significance. The wetlands, its seeps and its marshes are jealousy maintained and protected from all disturbance. Seasonal overgrazing has been abolished and the steep grass slopes recover a little more every year. The untrampled river banks are carpeted with all the bulbs, lilies, ferns, and pioneer shrubs of the Drakensberg’s unique flora. The river profile and the integrity of the stream channel are not besmirched by watering stock, gravel mining or indiscriminate recreational use. Wattle, American bramble, Scotch thistle and other noxious alien plants are vigorously controlled - not just on the property but in the wilderness drainage lines abutting its boundaries.

Biomonitoring stations have been established as part of the Dept. of Water Affairs catchment improvement programme - and incidentally, return some of the highest scores ever recorded by the programme. Nothing could give clearer indication of the health of the river’s invertebrate communities. The river and lake are home to a rich tapestry made up of vibrant communities of endemic creatures, from cranes nesting in the wetlands, to the cryptic and extremely rare semi-burrowing tree frog, Leptopelis xenodactylus. Grass owls, Cape clawless & spotted neck otters, fish eagles, and dare I say it, two species of indigenous minnow, all thrive. Cormorants, bitterns, herons and kingfishers abound. Every day the sun sets behind blurred clouds of stonefly, caddis, midge or mayfly dancing against the horizon. The hierarchy of aboriginal species that find sanctuary in its folds is utterly amazing - from Rhagionid flies to the great raptors like lammergeyer and black eagle.

In short, the habitat is conserved, repaired and preserved - and it ensues while providing full and honourable employment for the breadwinners of eight families. It happens, not in spite of, but because of the trout! Trout-fishing is the single imperative underpinning the commercial viability of the business construct. It is income generated by trout that funds its land management strategies - and that drives a management model striving to maintain the natural ecology.

It is a clear model of the practical application of the concept of "Sustainable Utilisation". Its implementation - not just as a buzzword in promotional material, or a notion to be batted back and forth by cobweb-covered academics, but rather, as a reality around which real people and communities build their lives - is an ideal towards which global humanity looks for salvation.

The authors of this anti-trout crusade publish under a cloak of authority, representing formal academia. From behind a screen of academic credibility, their summations go a great deal further than one might expect from an open mind presenting objective data. And it is done it in the name of "The Champion of Dealing with Threats to Biodiversity". Yet their arguments, too often, avoid confronting too many of the real issues - or engaging in the debate in a way that allows this thing to be taken forward with any objectivity -choosing instead to present trout as the foremost threat - more by implication than through honest review of all the available data. The anti-trout lobby disregards any data that does not affirm its position - but then includes data which is barely more credible or relevant than my own ranting.

Wolf Avni - Trout Farmer

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Response from Dr Neels Kleyhans, 
Department of Water Affairs and Forestry 

Information on the policy related to trout farming was provided by Dr Suzan Oelofse (DWAF Directorate: Water Quality Management). Information on the impact of trout on macro-invertebrates was provided by Ms Christa Thirion of the IWQS.

I. Impacts of trout on indigenous fish

The impact of trout on indigenous species vary from species to species and from stream to stream. Generally, however, the experience that I have had with trout through many years indicate that they most often do have a highly detrimental impact on indigenous species. This includes some stomach contents analysis. The abundances of small species such as several minnow (Barbus) species, shell-ear (Southern Kneria), suckermouths (Chiloglanis) and mountain catfish (Amphilius spp.) are often severely reduced by trout in the rivers of Mpumalanga and the Limpopo provinces. These observations can be considered as incidental but can not be ignored.

Controlled experiments have been suggested to properly quantify the impact of trout. Although such experiments may have some value it seems to me that available (including specialist knowledge) information on the known impacts on indigenous fish should be collated to provide an overall picture of the impact of trout in South Africa.

Of special concern in some areas, are so-called "put-and-take" trout angling systems where trout abundances are kept artificially high (i.e. higher than the "trout carrying capacity" of the stream). This stocking approach put the resilience of the native biotia to disturbance under continuous stress and can hardly considered to be compatible with sustainable use.

It has also happened that species other than trout were considered to be "trash" fish and were treated with contempt and disgust. Cases exist where Incomati Chiselmouth and Large Scale yellowfish were removed in large numbers from streams because they were considered to be in competition with trout.

II. Impacts of trout on macro-invertebrates

Surveys conducted for the River Health Programme during the last 6 years in Mpumalanga indicate a lower abundance of macro-invertebrates in streams where trout were introduced. Macro-invertebrate diversity does not appear to have been impacted.

A reduction in the abundance of macro-invertebrates can have a direct impact on the food source of indigenous fish species.

III. Policy on trout introductions

The Dept of Water Affairs have no policy on trout introduction as this is the domain of the Nature and Environmental Departments of the various Provinces.

IV. Policy on trout farm

In general, two points relating to ecological aspects are important here:

1. Due to the high concentration of trout, intensive feeding and treatment for disease on trout farms, water quality problems may arise from such farming units.
2. Relatively high volumes of good quality water are required for trout farming.

Based on article 21 of the National Water Act (1998), a venture such as aquaculture (including trout farming) may include a number of activities that can be listed as water use:

21. For the purposes of this Act, water use includes -
(a) taking water from a water resource;
(b) storing water;
(c) impeding or diverting the flow of water in a watercourse;
(e) engaging in a controlled activity identified as such in section 37(1) or declared under section 38(1);
(f) discharging waste or water containing waste into a water resource through a pipe, canal, sewer, sea outfall or
other conduit;
(g) disposing of waste in a manner which may detrimentally impact on a water resource;
(h) disposing in any manner of water which contains waste from, or which has been heated in, any industrial or
power generation process;
(i) altering the bed, banks, course or characteristics of a watercourse;

However, this does not automatically imply that licenses are required for trout farming. This will depend on whether the water use is listed in Schedule 1 of the Act, whether it is an existing lawful use or whether it is permissible according to a general authorization.

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Response from Dean Impson, Western Cape Nature Conservation Board

Working policy of the Western Cape Nature Conservation Board on trout
angling and farming

Our attitude to trout in this province from purely a nature conservation
perspective is negative as both rainbow and brown trout have established
invasive populations in mountain streams here at the expense of indigenous
fishes and other fauna.

However, we acknowledge that socio-economically the rainbow trout has been an asset in this province. This species is the backbone of the freshwater flyfishing industry here as well as our freshwater aquaculture industry. Both industries are substantial.

The above factors dictate our approach to trout in this province which can
be itemised as follows:
1. The two trout species enjoy no protection from our nature conservation
Act. We ceased producing trout using nature conservation funding in 1986.
2. Being a nature conservation organisation our focus is the conservation of
natural ecosystems and ecological processes as well as indigenous species.
3. Trout are well established in several rivers on our reserves,
particularly in the Du Toitskloof area of the south-western Cape. We entered into an agreement with the Cape Piscatorial Society in the late 1980's whereby they manage angling for trout in these reserves and provide as with an income for entrance permits to these reserves by visiting anglers.
4. Trout are still produced at our hatchery at Jonkershoek, but this is done
by aquaculture research staff at the University of Stellenbosch using their
funds. This hatchery is over 100 years old and has valuable facilities for
fish culture. We do not have the staff or budgets to do fish culture work
ourselves but allow the university to do this to prevent a national monument facility from falling into disrepair.
5. Our policy regarding fish stockings is to allow fish species including
trout to be stocked by the public via a permit into farm dams in areas where they are legally present and established. Rivers may only be stocked with indigenous species by nature conservation staff as part of an approved
rehabilitation exercise.
6. No catchments without trout (i.e. "new waters") may be stocked with
trout.
7. Our policy with regard to trout farming is to support this in
non-sensitive areas where trout are legally present. New applications to
farm trout must go through the E.I.A. process and have the support of
members of the Western Cape Aquaculture Working Group of which we are a member.
8. Several old trout farms are in highly sensitive catchments. Our approach
here is to try and persuade the farmer to minimise his impact on the natural
environment through improved management procedures. We have had considerable success with certain farmers in this respect.

In summary, we have a balanced approach in this province with regard to the management of trout angling, stocking and farming. This has culminated in an excellent relationship with organised trout angling here. We have reached the point where organised trout angling and farming supports conservation projects. Rainbow and brown trout are not viewed as pest species in this province. However, they are also not regarded as having a beneficial impact on ecosystems. This impact has been negative and may be highly negative in some rivers but needs to be quantified in this province.

Dean Impson
Principal Nature Conservation Scientist
Scientific Services

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Response from Professor Bryan Davies, Ecologist, University of Cape Town

As an ecologist specialising in river ecosystem functioning, conservation and management I am TOTALLY opposed to the introduction of trout or any other alien aquatic species for that matter. I have maintained this stance during the nearly 30 years of my career in freshwater research. Indeed, I was vociferous during the 1970s and 1980s when the Cape Nature Conservation Department was actively rearing and introducing trout into streams in the Western Cape, at the request of trout fly fishers. (The Department still has a hatchery but as far as I know they do not introduce trout to 'new' streams....the fly fishermen do).

Trout, Bluegills, Bass and other introduced species have wrought unquantifiable damage to our streams and rivers pushing endemic fish towards extinction and destroying the (now as we look in detail) high endemicity of invertebrate species of our systems. Unfortunately little data is available on the overall damage because when trout and other species were first introduced, we had no idea of the biological diversity of organisms under threat from them.... many species may well already have been pushed to extinction.

I am of the opinion that where trout form a major tourist attraction - for instance in the montane environs of Mpumalanga around places like Dulstroom, there is little that one can do or should do to alter the status quo. I also have few problems with so-called 'trout farms' as long as they are monitored and are designed so as to be unable to release fish to nearby natural water bodies. However, where a few sport fishermen ply their sport such as in the headwaters of Drakensberg and Western Cape rivers, then every effort should be made to remove the alien species and to promulgate sufficiently heavy legislation to deter deliberate introductions. Species such
as the Clan William Yellowfish which are under threat from alien fish make much more exciting fishing species than the aliens and efforts should be directed towards their conservation and to the eradication of aliens. A recent conference on alien species revealed that every day some 100 000 species globally were on the move, as it were, to places where they simply should not be, through intentional and unintentional human activities; in the USA the costs of invasive alien species topped three trillion US $ in 1999! If that is not sufficient argument for the eradication of aliens and the prevention of deliberate introductions then I do not know what is. South
Africa is a signatory of the Convention on Biological Diversity; as such we have a duty to prevent further destruction of the total environment simply for the pleasure of fly fishermen.


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