FISH YOU WERE HERE II: The Empire Strikes Back

Continued from last night..

It probably seems unlikely to any readers under the age of 40, but only half a century ago Great Britain was the hub of the greatest empire that the world has ever seen. On maps in schoolrooms all over the globe great swathes of the world were coloured pink to denote the fact that they were a pivotal part of the empire on which the sun would never set. Although the impact of the British Empire on the commerce, politics, and defence of the former colonies is well known, what is not widely realised is the effect that centuries of empire building had upon the Zoology of British colonies all over the world, and, indeed upon the motherland herself.

Whilst working on this two-part article we were surprised to find quite how many species of fish that we had assumed were native to the British Isles, were in fact no such thing, and were amazed how many British fish had been translocated to a pond or stream in some corner of a foreign field.

The Tench, for example, is an unassuming, bottom living fish found in still, and slow-moving waters found across Western Europe. Although they are edible, anyone who has tried to eat a tench souffle for example, will confirm that they are far from being the most appetising of Mother Nature's under water subjects. It is surprising, therefore, to learn that Frank Buckland - the founder of the Acclimatisation Society, whose name has cropped up in these pages before - introduced them to Madras in India in 1866 and again in 1873, 1874 and 1876. They were introduced to Tasmania in 1858 and from thence to the mainland, by the Australian branch of the society, also introduced them to New Zealand a few years later.

It must be admitted that Buckland could well be perceived as a zoologist of the "because I can" brigade, and there is very little that one finds out about him which is really surprising. However, the same species was introduced into Indonesia - by the Government - in 1927, and apart from remarking that Johnny Foreigner is a rum cove, it is hard to fathom out why they undertook this exercise. They were introduced into South Africa in 1910 - bizarrely enough - as a food source for another introduced species; the large mouth bass. They were introduced into Rhodesia (now Zimbabwe ), in 1938, Canada (1915) and the United States in 1877. In these cases, however, the motivation is an obvious one - the fascination that so many British expats have with a dangling worms on strings into muddy water of a weekend.

Rudd - another humble Western European species of no great economic importance have also spread across the globe as a result of Empire. On this occasion it was the French Empire who introduced this fish to several of them of their North African colonies for reasons best known to themselves. Curiously they have also turned up in Canada and parts of the United States with no one knowing how they got there, although other introductions to the USA over the years have been recorded for both food and sporting purposes. They were amongst the first species to be shipped to New Zealand aboard HMS British Empire in 1864, although none survived the journey. From 1971 onwards fertilised Rudd ova were smuggled into New Zealand illegally, and the species has now become established on both north and south island to the detriment of local wildlife.

The common perch has been introduced to Cyprus (1971), Spain (1970), and South Africa (1915) as well as New Zealand, Australia and to the Azores - all for sporting purposes. However, what was most surprising to us - at least were the foreign species which have become a familiar part of the British ecosystem. Carp, for example, were originally natives of central Asia, but were introduced to Britain some time in the middle ages. A book published in 1486 notes them as uncommon in British waters, but they soon spread across the country. Although most fish were introduced into the UK for sporting or gustatory purposes, at least four species arrived purely as a result of the aquarium trade. The two colonies of Guppys which survived for some years in artificially heated water in the UK are common knowledge, but less well-known are a species of cichlid which became established in a Liverpool Canal after a tropical fish shop went bust, and a small but viable population of the North American pumpkinseed in Somerset, and another one in Surrey, which have since died out although another colony in Hampshire remains healthy. More problematical are the bitterling which have been recorded from a few isolated locations in Lancashire, Derbyshire and the Welsh borders. These have long been assumed to have been introductions because although these are popular aquarium fish - especially during the 19th and early 20th century - they were popularly believed only to exist in central Europe, Asia Minor and eastward across Eurasia. However, the recent discovery that the pool frog is actually a British native, and furthermore has been recorded in exactly the same locations as the British bitterling, suggests that this attractive small fish may indeed have been a British resident all along.

Perhaps the most striking piscine introductions to British waters are the Zander and the Wels. Both originally natives of central Europe and Asia Minor, they were both introduced to the UK by Frank Buckland's cronies. The Zander is an extremely aggressive species which has disastrous effects on the native livestock of any area which it colonises, and the wels - or European catfish - is not only the largest freshwater fish in the world, but has even been rumoured to have eaten people. During the summer of 2002 the present authors led an expedition to Martin-Mere in Lancashire where "something" had been reported attacking swans on a nature reserve. It turned out to be a wels catfish, and we estimate that it is in excess of eight feet in length.

There is a popular misconception that the Zander is a cross between a pike and perch. This is complete nonsense, but the belief lives on. It is shaped vaguely like a pike, and has the bars and coloration of perch, but is not closely related to either. It has the voracious appetite of a pike and as it can also tolerate brackish water, its incursions into British waterways are viewed very seriously indeed. By 1996 this species had been reported from the Midlands, East Anglia, Kent and was making serious incursions into the Cotswolds. Despite all efforts to eradicate it, and its special position within the Wildlife and Countryside Act 1980, which condemns it to an ignominious death, it looks as if - sadly - this piscine predator is here to stay.

Global warming, and the attendant climate changes have already seen some exciting additions to our marine fauna. Such species as barracuda and even great white sharks have been noted from British waters in recent years. It is tempting to theorise that as our climate changes further, more freshwater species from warmer climes will become established. The White Cloud Mountain Minnow - a Chinese species which one of the present authors remembers catching as a child in Hong Kong - has reached as far afield as Madagascar and Columbia. Other species familiarly kept by aquarists have also spread around the world from their original locations. When our great grandchildren go down to the local pond with jam jars and nets in the 22nd century, what species will they bring back with them?