Debate on the Trout Controversy
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Response form Prof Paul Skelton, Managing Director,
South African Institute for Aquatic Biodiversity
The SAIAB does not have a formal 'policy' on trout. It is not our task or
role to have such a policy - that is for the various nature conservation
agencies in the country. The SAIAB would not support any action that
contravenes any law of the country and, in general, would favour and support
actions and decisions that give priority to the conservation of indigenous
fauna and flora. Individuals employed by the SAIAB may, or may not, have
their own 'views' on the issue of introduction of alien organisms but as a
scientific Institute we approach issues independently from a scientific
perspective and on a case by case basis depending on the issue. The SAIAB
is concerned with issues concerning the conservation of (aquatic)
biodiversity and, in general, from this perspective, the introduction of
alien organisms to the natural environment will involve impacts and is
therefore considered a negative factor.
Studies, including some of our own,
have shown that 'large' predator species such as trout and other gamefish
species, have had a serious impact on indigenous fish populations and
probably the populations of other aquatic organisms, in environments into
which they (the aliens) have been introduced.
Speaking more personally I believe that priority ought to be given to the
conservation of indigenous species but would recognise that there are
usually various factors behind the introduction of alien organisms and that
in some cases these factors might be of deciding importance. Trout in
aquaculture and the promotion of tourism and recreational angling are cases
in point. For example in places where trout already exist and form the
basis of a valued fishery there is a case for continuing the use of such
natural waters as for recreational angling. At this point in time where
most suitable trout waters have been stocked already I personally would be
extremely cautious and circumspect about introducing trout or any other
alien to any new or unstocked waterbody or area. Certainly I would require
that no action be taken until a thorough scientific investigation of the
situation has been completed. Where threatened indigenous fishes are
involved I would also be firmly in favour of taking steps to rehabilitate
the system such as the active eradication of alien species and
re-establishment of indigenous species.
In short, conservation, whether it be dealing with the impacts of alien
predators or otherwised damaged or affected environments, is a question of
dealing essentially with people and a broad spectrum of different interests.
Where there is clear conflict of interest but no unambiguous or exclusive
single right point of view involved then a balanced outcome between the
parties must be negotiated. I believe this to be the case for trout in the
environment in Southern Africa.
Prof Paul Skelton, SAIAB (Formerly JLB Smith Institute of Ichthyology)
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Response from Dr Johan Engelbrecht,
Conservationist
Most of our river surveys has indicated that trout has a negative effect on
our indigenous fish populations. For instance in the case of the threatened
Treur River barb (Barbus treurensis), their distribution is sharply ended by
the presence of trout beneath a small waterfall (Christmas Pools). This
waterfall serves as a barrier to trout, isolating the population above from
predation by trout. No specimens of this threatened species occur beneath
the waterfall although there is indications that this species probably
historically occurred much more widely in the Blyde River. Similar trends
are repeated in all areas where trout is stocked, namely an absence of
indigenous fish or very low numbers of indigenous fish. This is sharply
dissimilar to areas in the same rivers or types of rivers where trout are
absent. A few surveys have also indicated the presence of abundant remnants
(bones) of indigenous fish in the guts of trout. This is not always the
case, as indigenous fish numbers can be highly reduced in some places and
one would not expect their presence abundantly in the guts of trout.
It is important that the FACT that trout have a negative impact should be
excepted so that the problem can be managed and not ignored by fanatics.
Our policy is not allowing for the release of trout in streams which is not
part of the historically proclaimed "trout waters". These areas
presently
include most of the streams with favorable conditions for trout in the
province. Hatcheries should also be restricted to these areas as escapees
always occur.
Dr Johan Engelbrecht, Conservationist
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Response from Pat Hopkins - PICA Journalism award for
Environment, Wildlife and Conservation
My view is that our river systems are under severe threat. There is one
reason for this crisis - ignorance. This ignorance manifests itself in many
ways: the placing of obstructions and barriers, such as dams and weirs, in
rivers without adequate environmental assessment; excessive water
extraction; poor farming practices; pollution; the dumping of indigenous
fish, such as catfish or barbel, into rivers where they do not actually
occur; and the introduction, mainly for sport, of alien fish species.
It was the British colonialists, with their dangerous naiveté, who
introduced alien fish to South Africa. Unfamiliar with the fine qualities of
our indigenous fish, exotics such as bass, carp and trout were introduced in
the late 19th century to keep British civil servants happy. Historical
records, prior to this, show that indigenous fish, unlike now, were once
abundant in all areas of South Africa. This is not the case today.
A good example of the pressure on indigenous fish is the Western Cape. Of
the 18 indigenous freshwater fish in the region, 13 are endemic. All the
endemic species are threatened, nine endangered. The speed of the decline is
the most alarming factor. Twenty five years ago, six were threatened, one
endangered. the Clanwilliam sandfish was unlisted in 1977 - today it is
critically endangered.
In this region indigenous species are only abundant where alien fish have
not been introduced and agricultural development has been insignificant. The
trout is regarded as directly responsible for the declining numbers of two
redfin minnow species in mountain streams. The impact of alien fish on
invertebrates, amphibians and micro-organisms has yet to be quantified.
The threat of these exotics to indigenous species are many. They brought
with them new parasites and diseases. All game fish are predatory. Their
introduction as caused an imbalance. They are carving niches in, and often
dominating, water systems.
I believe that the greatest damage is caused by the wealthy trout lobby who
are more concerned with their exclusive sport than with the environment. The
debate is as filled with red herrings as that surrounding the 4x4 on beaches
debate. But it all boils down to vested interest. The lie goes that tourist
dollars are lured by trout fishing. This has led to uncontrolled damming of
rivers, particularly in the Mpumulanga highlands. In this case there is a
double-whammy of problems. Not only are indigenous river species affected,
but the flow of water to the Lowveld is being reduced and cranes that once
bred on the highlands do not breed in dammed areas, only wetlands.
The fact is that few tourist dollars are attracted by 'our' trout because
our harsher rivers make them puny in comparison to those found elsewhere.
And ecotourism is a bigger lure.
The simple answer is to eradicate all alien species, whether they be wattle
or trout. But this could be nearly impossible to achieve. The next most
obvious step would be greater regulation of waterways. This would require
closer co-operation between the departments of Agriculture, Water Affairs
and Environment. What is envisaged is the establishment of a statutory body
to set up reserves for indigenous fish and to police our waterways. This
body would also be responsible for issuing fishing licenses - and hopefully
they would levy trout fisherman with the true cost of their sport to the
environment. Most importantly, we need to educate the public and change
colonial mindsets if our attitudes to the environment are to improve. This,
ultimately, is the only way ignorance can be overcome.
Pat Hopkins - PICA Journalism award for
Environment, Wildlife and Conservation.
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Article
Response from Johan Brummer, Councillor
My blood runs cold everytime I see or hear the word TROUT.
I live just outside Plettenberg Bay, an area which is subject to enormous
pressure by developers. With an absolute avalanche of properties and
developments coming on the market, every developer has to out do the one
before in some way to make his development more attractive to the buyers.
We have had a very bad experience here about a two years ago when a
developer
wanted to do a twenty chalet development and had decided to use TROUT as a
drawcard to market what would otherwise have been a mediocre development.
The developer's field is actually ichthyology, so he built two breeding
facilities and stocked these with fry in order to release them in the stream
on the property, the Salt River. This he claimed was done with "verbal
consent" from CNC at Jonkershoek, a fact which they denied when it came
down
to the crunch.
When we became aware of what was going on, we demanded that an EIA be done.
It was then that the two illegal breeding facilities were discovered
together with two huge dams. One dam had already been stocked with trout. We
were aware that the rivers in our area contain populations of redfin
minnows, and that trout could wipe them out. The Environmental Consultant
tried to rush through the EIA process, and when the public scoping meeting
was held it emerged that the superficial study which had been done on the
river had not even been written up!!!
There are two rivers in close proximity to each other, the Salt and the
Buffels. One of the breeding facilities had been erected on the banks of the
Salt, and the other in the catchment of the Buffels. The Buffels river was
found to have viable populations of redfin minnows but the Salt river
inexplicably had no life in it whatsoever. (One of the people who attended
the public scoping pointed out that she had worked on a property riparian to
the Salt River and had in the past seen redfin minnows there.) We had called
on Dr Jim Cambray for his help which he generously gave, and judging by the
failure of the authorities to act against the developer for his proven
illegal activities, we as laymen would have had no chance of stopping the
introduction of trout without expert assistance.
The developer's consultant, argued that it was quite acceptable to stock
these rivers with trout, notwithstanding the fact that his own published
work done on the streams of the North East Cape (Ugie/Elliot/Maclear)
highlighted the severe damage that such a course of action could lead to.
The authorities felt that the EIA had been too superficial and over too
short a period, one weekend in winter, and that a proper investigation
stretching over a longer period should be done. The developer then blamed
the person who claimed to have seen redfins in the river years ago, and
started legal proceedings against her for the extra costs of doing a proper
investigation!!!
The water in these rivers is very acidic and not really suitable for trout.
Being an ichthyologist the developer was aware of this and had already at
that stage set about altering the ph of the water by carting in large
quantities of agricultural lime stone, some of which he had already dumped
in the upper reaches of the Salt river. He was forced to remove this by our
local CNC officer, Henk Nieuwhoudt. He was the only official who took any
action on the developer's illegal actions.
Everything I have heard, read and observed tells me that trout do not live
in harmony with most of our indigenous fish. There is no way in which these
fish can be effectively impounded and will spread to the detriment of
indigenous fish species. Granted trout fishing is economically beneficial to
the areas where they have been introduced, but the impact cannot be confined
and there is no reason why the environment and the rights of others to have a pristine environment should be sacrificed for the profit and enjoyment of
a few.
The sad part of this story is that the redfins in the Buffels River will now
almost certainly die out. A landowner in the catchment (soak area) impounded
the upper reaches of the river to create an ornamental feature on his Polo
estate. This soak area is what fed the stream in times of drought. The river
has now failed for the first time in human memory. No flow in this river
ultimately means no redfins. The authorities have been informed of the
illegal dam and the removal of topsoil in the soak area and have called on
the owner to do an EIA. He seems set to drag this out for years, and in the
meantime the river has died.
This story has a sad ending, but that does not derogate the huge effort and
many hours of work that was put in by people such as Jim Cambray to prevent
alien fish from being released in these rivers.
Thank you for giving this matter your attention and raising awareness of the
problem.
Johann Brummer (Councillor)
Plettenberg Bay.
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See Nick James' response
See Johann Brummer's full reply to Nick
James letter
Response from Dr Bob McDowall,
National Institute of Water and Atmospheric Research, New Zealand
I became
seriously concerned about trout impacts way back in the mid
1960s, and wrote what I think is the first serious published critique
on the question - see: McDowall, R.M. 1969. Interactions of the
native and alien faunas of New Zealand and the problem of fish
introductions. Trans. American Fisheries Society 97(1): 1-11. I
have since then, written repeatedly on the topic.
Since brown and rainbow trout were introduced to New Zealand in the late 1800s,
there has been a decline in abundance of native fish; this decline is often
attributed to the impacts of trout, though evidence is largely circumstantial
and habitat deterioration may have had a role (both impacts are likely). Mostly,
decline in native fish abundance resulting from trout is attributed to trout
predation, but other mechanisms are likely. Studies of trout population/stream
ecology show that trout may consume the entire annual benthic insect production
of streams, leading to a trophic cascade that is evident in proliferation of
periphyton in the relative absence of invertebrate grazing. Changes in the
behaviour of both benthic invertebrates and native fish are believed to have
also resulted from trout predation. The observed level of benthos predation
suggests that an additional impact of trout on native fish may function through
a feedback loop-native fish may be less able to obtain food owing to changes in
their own behaviour, in insect behaviour and in insect abundance, all of these
induced by trout predation.
Additional comment: It is also very clear that trout have caused major
declines in the abundance of pelagic lacustrine life stages of some native
galaxiids, to the extent that in the early 1900s, trout condition declined
seriously owing to food shortages. The galaxiids were replaced with a pelagic
smelt that has been able to withstand sustained trout predation.
Managers of NZ's trout fisheries, the Fish and Game Councils, now have a
policy of not liberating trout into waters that do not already have trout in
them. Note, that virtually all of New Zealand's trout fisheries (all based on
introduced species) are self-sustaining, and management stocking for angling is
undertaken in very few waters.
Dr Bob McDowall, New Zealand
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Response from Tim Rolston, Ultimate Angling
Having had an admittedly brief look at your article
about trout I feel moved to respond having been involved with flyfishing for
trout and other species, indigenous and others for many years. Although I
perceived some cursory attempt at a balanced argument it became apparent that
there was some considerable bias and that the facts as they are, are not well
represented. I also hail from a scientific background and as such there is a
great deal within the article which is anecdotal and some information which is
blatantly untrue.
Firstly unlike a great many alien species in the country, trout (both rainbow
trout and brown trout) are not in the true sense invasive. They have highly
restrictive temperature ranges which prevent movement into lowland and high
temperature environments. Although it might be argued with some validity that
introduction of any alien species is bad practice it has to be said that in many
instances if one is to hold mankind up as the most important species, ( a view
to which I don't subscribe) then these introductions are of benefit and are
equally inevitable . Simply a function of mankind's ingenuity and intellect
giving them temporary advantage in terms of selection of the species.
There are a huge number of aliens which are far more invasive, far more
dangerous and far less useful than the humble trout and I can't see why a
supposedly scientific forum should decide that trout are to be targeted.
It should also be noted that there is at least an inference that trout are
responsible for loss of naturally occurring species whereas for much of the time
evidence of this is anecdotal and the factors associated with water abstraction,
pollution, water degradation, damming of streams etc are at least as likely to
have had a detrimental effect.
So I might suggest that firstly a little attack or two on destructive farming
and industrial practices would be in order and perhaps some mention being made
of the fact that for much of the time trout anglers (who are also frequently
conservationists) are invariably the first and often loan voices who fight
pollution, water abstraction, damming and wetland damage. I can tell you without
a shadow of a doubt, that whilst I would accept trout are alien and perhaps
undesirable in the longer term, without them and the people who frequent the
waterways in pursuit of them, the rivers, dams and streams of our country would
be in a far worse state than we currently find them and more to the point those
same anglers already sponsor work in terms of rehabilitation of yellowfish
habitat and research into indigenous species.
So when yourselves and your readers give up eating alien meat, boiling alien
vegetables, growing alien flowers, wearing alien fabrics, lying under alien
trees, consuming wine from alien vines, buying from pollutant industries and
consuming goods from environmentally unsound farms then give me a call and I
will willingly assist in irradicating the trout. Until that time I am simply
going to carry on monitoring the environment which my beloved trout and a host
of other species inhabit, and try to preserve them for everyone and everything.
I do hope that you might find space in your pages to note this letter because as
it stands the anti trout lobby is getting an unfair crack of the whip and are
sitting in front of their computers full of righteous indignation and alien food
stuffs, feeling very pleased with themselves that they are doing so much good.
Tim Rolston,
Ultimate Angling,
Cape Town
For response to this piece from Dr Jim Cambray, conservationist, please
visit mg17.htm
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