Monday, 15 April 2013

Sunday, 9 November 2008

ALIEN SPECIES

Following last week’s mention of the possibility that Zander may be in the lochs I received a mail from an enquiring angler as to why the fish if indeed there are any should be killed?
I will attempt clarify the stance taken by the club below.


Well the simple answer is that they do not belong in the lochs, and if Zander are present they have almost certainly been introduced by anglers with some ulterior motive such as creating a stock of new fish to fish for, and whilst one can see the thinking behind such a move it is highly irresponsible, ill thought out and illegal.

No fish may be moved without a licence from the appropriate authority. Such introductions completely alter the ecosystem of the receiving water and in the majority of cases the effect is detrimental to that fishery.


What would be the point of keeping such fish alive, where would they be moved to given the restrictions on fish movement? The fish should be humanely dispatched and given to the loch keeper who will inform the relevant authorities in order that they may carry out any tests they deem necessary. Zander have been legally classed as a dangerous animal and on no account should such a fish be returned to the lochs if caught.


To see the results of ill thought out and inadvertent fish introduction one need look no further than Loch Lomond, and the deleterious effect Ruffe have had on the indigenous and rare Powan, predating on their eggs to such an extent their very future now hangs in the balance. The ecosystem in Loch Lomond has now changed from the original and because of this further changes will take place. Selective removal of Ruffe from Loch Lomond is not possible.


On the bush telegraph there are stories of Roach, Carp, Sturgeon, Chubb and Signal Crayfish being in the lochs. No evidence has been found to support these assertions to date. The fish considered to be indigenous to St Marys Loch and the loch o the Lowes are migratory fish Sea Trout and Salmon, Brown Trout, Pike, Perch, Eels, 3 spined Sticklebacks and possibly Arctic Char. Any Angler catching a fish not mentioned above should dispatch the fish and give the fish to the loch keeper along with any relevant information so that the matter can be handed over to SNH for further investigation.

There are serious penalties (Fines of up to £1000) for the introduction of alien species, and we as a club we will work with the relevant authorities to prosecute any individuals engaging in such activities. The following is the viewpoint of Scottish National Heritage via the Tweed Foundation.



WHY ALIEN SPECIES MUST BE KEPT OUT OF THE TWEED

BIOSECURITY is not a word that is familiar to many – yet, but it will become so in the future. With the globalisation of trade and the increasing numbers of people moving around the world, the transfer of new species of plants and animals, both accidentally and deliberately, from one region, country or continent to another is becoming an increasing problem.
Some people mistakenly think that by introducing new plants or animals to an area, they are doing a good thing, increasing species diversity or making a new resource. However, an artificial, man-made, collection of species does not have any value as a group – there are hundreds of species of animal in Edinburgh Zoo, for example, many of them of great interest in themselves, but as a community, they have no value or interest. It is the natural community of species found in an area that is of interest, the “biodiversity”, as these are the plants and animals that naturally belong to an area and have evolved together over time.
Every time a new species is brought into an area, it actually reduces the naturalness of that area, making it more artificial, more like a zoo or botanic gardens. New species also make an area less distinctive and more like other places – for example, on the Tweed, only the fish species that can cross salt water at one stage or another of their life cycle are native to the river, because there has never been a freshwater connection between the Tweed and any other river by which purely freshwater fish could reach it.
The history of the south and east of England however, is quite different – at the end of the Ice Age, when the North Sea was still partly frozen, there was a large, freshwater lagoon off what is now the Dutch coast into which both the rivers of the south and east of England and those of the northwest of the European continent drained. Purely freshwater fish – such as Pike, Perch, Roach, Rudd, Dace, Barbel etc. are therefore native to the south and east of England but not to the Tweed or to the rest of Scotland or the North of England. Every time therefore that one of these freshwater fish is introduced to the Tweed, it makes the Tweed less distinctive and more like the South of England and continental Europe.
Introductions of new species weaken the local identity of an area, making it more like any other, a process called “Ecological McDonaldisation”, since the way in which fast-food chains are changing local and national differences in food and eating habits as they spread through the world is exactly parallel to the way that ecological differences between areas are being destroyed by introductions of new species. While it is true that new species (and new restaurants) can be a resource, sometimes a very valuable one, it is at the expense of natural, local, identity, too high a price to pay for any supposed advantage.
There is also the point that introduced species are generally very difficult to eradicate once in the wild, so their introduction represents a permanent ecological change, and no one individual or group has the right to make such a fundamental and unalterable change. An animal or plant that may be useful or seem desirable to one generation may be unwanted or a pest to future generations. There are also the risks to native plants and animals from introductions – too many disasters have occurred all over the world from introductions and are well known, such as Rabbits and Cane Toads in Australia. Here in Britain we have had the near extinction of the native Red Squirrel by the American Gray Squirrel, the devastation of water birds by introduced American Mink and, most recently, the catastrophic introduction of Hedgehogs to some of the islands of the Outer Hebrides where the eggs of ground nesting birds had previously been safe from land predators and where the once large breeding populations have been greatly reduced. Hopefully, it will be possible to remove Hedgehogs from these islands, where they simply do not belong, but it is very much more difficult to remove freshwater species once they have arrived, making prevention the only real answer.

To view the complete picture click the link below.
http://www.tweedfoundation.org.uk/News/Updates/Downloads/downloads.html

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