Flyfish@ list members:

I forward the following message from the fishfolk list.  The
author/compiler Gene Buck describes incidents of folks maliciously
stocking exotic fish and, if known, the outcome.  If you tend to react
negatively to private individuals "playing God", then you might find some
of the following quite disturbing.  Be prepared. 

Erik Poole
Burnaby, BC

Malicious introductions
Date: Thu, 20 Nov 1997 15:21:02 -0500 From: Gene Buck Subject: Malicious introductions - summary - part 1 of 2 Here is a collection of responses that were sent to me after my Nov. 6, 1997, query about malicious introductions of aquatic species, with no judgement on my part as to whether any of the examples cited would actually constitute a "malicious" act. I have separated them into "referrals and citations" and examples" and have tried to not duplicate those responses already posted to the list. My apologies for any inadvertent duplication. I have also exercised some limited editing to help maintain the anonymity of respondents. Gene Buck, REFERRALS AND CITATIONS: 1) Malicious introductions has been a subject of some debate among invasion biologists. The "king" of all such knowledge is Dr. Jim Carlton, at the Smithsonian and Williams College. There are also some invasive species listservs. One list is from the California Exotic Pest Plant Council. The address is "" which may be subscribed to by sending the following message to "subscribe exotic-plants" 2) I highly recommend the following book which reviews many examples, plus gives you the full bibliography to fish introductions (legal and illegal ones): Lever, Christopher. 1997. Naturalized fishes of the world. Academic Press. London. ISBN:0-12-444745-7 3) If you have not been in contact with Leo Nico at the Florida and Caribbean Science Center, USGS, Gainesville, Florida, you should do so. As you are probably aware, his agency is charged with cataloguing exotic fish introductions. Leo is the senior biologist in charge of fish introductions. They have an enormous database of literature documenting exotic fish releases. His address is "" 4) Spencer, C. N, B. R. McClelland, and J. A. Stanford. 1991. Shrimp stocking, salmon collapse, and eagle displacement. BioScience. 42: 14-21. EXAMPLES: 1) I understand there have been several sabotages (in Scandinavia) to Salmo spp. rearing sea-farms where cages were destroyed and fish escaped to the wild. Perhaps, those escapees could be considered as non-native as they are the product of artificial selection/genetic manipulation. 2) This is from memory, so there may be some errors - On a small island (Lasqueti Island) between Vancouver Island and the mainland of British Columbia, there are a couple of small lakes. These lakes harbored threespine stickleback which had separated into a pelagic and benthic populations, believed to be distinct species, although not named until more work was done on their taxonomy. Since there was a proposal put through to make these lakes into ecological reserves, the people nearby introduced brown bullhead (a catfish) into one of the lakes to extirpate the sticklebacks. Their scheme worked. Dr. Don McPhail should be able to give you more information and correct the above. In the Champion Lakes provincial park, just north of Trail, B.C. and near the US-Canada boundary, an expensive program to eradicate long-nosed suckers and redside shiners was undertaken about 12 years ago. This was successful, and rainbow trout were re-introduced. The system was barren before access was developed into the lake, and rainbow and cutthroat trout were officially introduced into the lakes. The shiners and suckers were put in by people who thought that they would improve the size of the cutthroat. In fact, they exterminated them! Anyway, shortly after the sports fish were re-introduced, some party re-introduced the suckers and shiners, apparently solely to make the effort at eradication futile. Large posters had been put up to explain the rationale and why the coarse fish had proven to have a totally negative effect on the sports fishing. The other assumption is that the malicious introduction was done to damage the sports fishing potential. Since the culprits were not caught or identified, so far as I know, your guess is as good as mine. But, it was not done with the idea of improving the fishing, since the experience had shown that to be a disaster. 3) You know, both the Nazis in the early days of WWII and the Russians during the height of the Cold War claimed that the US was seeding their fields with Colorado potato beetles. I've never seen an investigation of the matter. Has there been one? There have certainly been liberations of monkeys by animal rights advocates, including in places where monkey might survive in the wild. Not exactly what you are seeking, but tangential. Finally, I am fairly certain that some of the piranhas liberated in Florida are liberated with evil intent, rather than just to get rid of them. A fair number of piranhas are liberated. Walt Courtenay at Florida Atlantic University could give you stats on them. 4) As you probably know many of the freshwater angling sport species have been widely introduced to promote fishing, most of the time legally, sometimes illegally. One clear example that comes to mind: In the early 1980's two German anglers brought fertilized eggs and juveniles European catfish (Silurus glanis) to the Ebro river in Spain, far away from the natural habitat of this east european silurid, where it can reach weights of 500 lb. The intent of these fishermen was to produce a new sport fishery, since in the part of the Ebro river where they were introduced there was a great abundance of carp (introduced by Romans), a natural prey of Silurus glanis. Now this is a very abundant species in the lower Ebro, with fish of more than 100 lb being caught, and competes with other predators such as zander, largemouth bass, pike, and perch (all exotic). 5) In many years of working with conservation of desert fishes, there have been several instances where largemouth bass (Micropterus salmoides) showed up very suspiciously in refuges built for the protection of Owens pupfish (Cyprinodon radiosus). The refuge areas are too small to support sportfish populations, so I can only assume that the introductions were made with malicious intent. There are those individuals in the local community who resent the use of public funds for the protection of nongame species, and it is my guess that this was the underlying motivation for the introductions. Neutral parties have reported this type of discussion in local bars. Such a matter is always subject to some speculation, inasmuch as the perpetrators of such things are not likely to make it known publicly. 6) We have one clear example of such a malicious introduction down here in Australia. We have a dry internal drainage (Lake Eyre system) with uniquely adapted native species. On the edge of this drainage is a large coal mine, and associated town, servicing a power plant elsewhere. One of the company employees was fired. In spite, he transferred exotic, duly hated European carp into a large retention dam near the town. The dam is the sole aquatic playground for this desert community and had been "adopted" by everyone including the local primary school to beautify, etc. As with most such events, our compliance officers failed to find sufficient evidence to take the matter to court ($60K fine applies). We've tried poisoning the system twice to no avail, so eventually these fish will gain access to the Cooper Creek system. 7) Here is a segment from a book chapter that Peter Moyle and Hiram Li just finished (2nd edition): "A better understanding of predator-prey relationships has lead to much less frequent use of predator and forage introductions as a management tool by fisheries biologists. Unfortunately, segments of the angling public are not as well informed. The unauthorized introductions of sport and forage fishes is a major headache of managers in many areas today and is a legacy of the enthusiastic use of this tool by managers in the past. In Montana alone over 200 illegal fish introductions have been recorded in recent years (Rahel 1997). In California, anglers have tried to establish northern pike in streams in reservoirs despite the danger it poses to native salmon fisheries and the high costs of eradicating established pike populations. 'Johnny Appleseed' introductions of percids and centrarchids to reservoirs in Oregon are occurring with alarming frequency." Smallmouth bass were illegally introduced to the Umpqua River, Oregon where it threatens the Umpqua chub, a federally listed species, and endangers coho salmon and cutthroat trout, two species at risk. Lake trout were illegally introduced into Yellowstone Lake. The consequences of which are not yet known. Li, H.W. and P.B. Moyle. In Press. Management of introduced fishes, Chapter 12, In C. Kohler and W. Hubert. In Press. Inland Fisheries Management in North America (2nd edition). American Fisheries Society, Bethesda MD. Rahel, F. J. 1997. From Johnny Appleseed to Dr. Frankenstein: changing values and the legacy of fisheries management. Fisheries 22(8): 8-9. 8) The following incident may fall into the category of "thoughtless introductions where aquarium fish/plants/organisms may have been dumped", but given the notoriety of the species, it is difficult for me to believe that there was not at least a subconscious maliciousness about the introduction. On 30 June 1992, a piranha (Pygocentrus nattereri) was captured by an angler in Lake Wilson, a reservoir of central Oahu, Hawai`i. The reservoir is a popular recreational fishing area and many people take their children there. A second, dead, piranha was found on moat in the Honolulu Zoo on 7 July 1992, and was believed by Zoo employees to have been released into the moat. When the moat was drained on 15 July 1992, a third, live, piranha was found. No more were found in open waters of Oahu until 21 February 1993, when another angler caught a second specimen in Lake Wilson. None have been found since, despite intensive searches. But an effort to find illegally imported piranhas on Oahu resulted in the seizing of 34 more from aquaria; Hawai`i State law explicitly prohibits the importation of piranhas. At about the time of the first capture, in early June 1992, police uncovered an illegal animal smuggling operation that in part specialized in bringing in noxious organisms to Hawai`i, including gars, electric eels, and scorpions (but no piranhas were found during the arrests). There is no evidence to suggest that this operation was in itself responsible for the released piranhas. The person who released the fish was never identified. Given the popular reputation of piranhas, it is difficult for me to believe that the person who released the fish into the reservoir thought that they were benign. I have no evidence that the releases were consciously malicious, but they were certainly done with ill intent. Fortunately, no more were captured and there is no evidence that the fish reproduced. But while the 37 piranhas captured or confiscated were retained at the Waikiki Aquarium they began spawning in a tank open to ambient light and temperatures, indicating that reproduction in natural waters of Hawai`i was entirely possible. Details of this series of events can be found in newspaper articles in the Honolulu Star-Bulletin, 13 June 1992, 3 July, 4 July, 7 July, 16 July, 25 July, & 31 July. The capture of the second piranha in Lake Wilson is mentioned in a Hawaii Fishing News article in April 1993, vol. 18, no. 3. Other information about the first specimen can be found in: R. L. Radtke. 1995. Forensic biological pursuits of exotic fish origins: piranha in Hawai. Environmental Biology of Fishes, vol. 43, pages 393-399. 9) I don't know of any documented cases, but there is some speculation through various rumors that a person named the "unapiker" plans to re-introduced pike into Lake Davis, Ca. Last month Ca. Fish and Game employees rotenoned the lake to get rid of the pike. Many locals were very upset about the poisoning of their water supply. It is speculated that some local has some pike sitting in bathtub ready to be introduced at any time. 10) E-mail Dr. John R. Moring or call the ME Inland Dept. of Wildlife and Fisheries. I recall that white perch were introduced into Moosehead lake as part of a conflict with the State's Fisheries department. In fact, the perpetrator deliberately dumped the fish in right in front of the department's office on the lake. Dr. Moring will have more details. Northern pike were also illegally introduced in the Belgrade Lakes of Maine. Unfortunately, no one knows who did it... so we don't know if the introduction was malicious. I might have the details of the perch introduction slightly askew, but the general idea is correct. 11) one example of a malicious introduction would be the periodic release of piranhas in water bodies in Florida. 12) I believe that many introductions that were intended to enhance sport or commercial fisheries have also been illegal and could be considered malicious in that they have impacted native fishes. I doubt that many such introductions are well documented in the literature but they tend to be common knowledge among fishery professionals in state fish and game agencies. While I was a graduate student, an individual transported or attempted to transport bluegill (Lepomis macrochirus) from Pelican Lake in Utah (where they were also introduced at some point in the past) to Kenney Reservoir, on the White River in Colorado. While this was not really a transfer between drainage basins, Pelican Lake is a more or less closed system and the White River is within the range of at least one endangered Colorado River cyprinid (Colorado River squawfish - Pytchocheilus lucius). I am not sure if this introduction succeeded but I do believe the responsible individual was prosecuted under the Lacey Act. I think that such introductions by "well-meaning" sportsman looking to increase the range of their favorite species have been common in the western US and continue to be a threat to native species. I would think that court records of fish and wildlife cases might be of value. 13) Mink were released from a fur farm some time ago in the UK, possibly during the 80s. They have become a serious pest of waterfowl. I do not know the details, but you may be able to get information from wildlife persons there. 14) As you know, exotic species are a particularly nasty problem in Florida, but most of them are the result of carelessness or stupidity. There are some marginal cases like Melaleuca that was intentionally introduced to dry out the Everglades to make the swampland developable, but whether one can confound maliciousness and greed is another question. 15) See the intro of Hydrilla into bass fishing lakes in the south. Bass fishermen think its great (as catch rates and sizes go up for a few years) then the stuff takes over and chokes the lake/impoundment and we have to resort to spraying, etc. Contact the LA Dept of Wildlife and Fisheries for info on this stuff. "" is their email address. 16) There are very tight restrictions against exotic fishes in Alaska. Truth be known, the legal aspects have little to do with preventing successful introductions by well-intended but mis-guided anglers, etc. What keeps these fish from taking hold is our severe winters. They can't make it through their first one, even if they do breed successfully; introduced fish and any of their progeny are doomed when their first winter arrives. However, climate warming may change this. Individuals are studying the effects that warming trends may have on the success of resident fish in extending their ranges within Alaska, and on the success of non-resident species invading Alaska, whether by natural or human-supported means. So, to your question. I'm having a hard time understanding what you are after. Probably because I don't know the definition of a malicious introduction. To destroy an ecosystem? To ruin someone's fishing hole? Even more important why is this important to know? From a resource/biodiversity/conservation standpoint, is it not enough to know that a species was or was not introduced successfully? Why is motive important? People convicted of illegal introductions (has anyone ever been?) would not be convicted for their motive, rather for their action. 17) We have had several suspected malicious introductions of nonnative fishes into waters of Montana. Walleye have been found in several reservoirs where not officially stocked. Also we have found brook trout moved into upper reaches or streams or mountain lakes, most likely by anglers who preferred to fish for brook trout. In one case, we had placed a fish migration barrier on a stream to prevent re-invasion by brook trout in an upper portion of the stream where we removed brook trout to protect a native westslope cutthroat trout population. We are extremely concerned about illegal (malicious) introductions of nonnative fishes which may thwart efforts at conservation and restoration of native species. Mike Young from Wyoming (email: /S=M.YOUNG/ has similar stories for some areas where native trout were restored in Wyoming. 18) It is my understanding that northern pike and white bass were both illegally, but intentionally, introduced to and transported around California by private party anglers. White bass were also introduced on a limited basis to one dead-end watershed with peculiar water quality problems near Santa Barbara by the Department. Both required extensive multimillion dollar rotenone-based eradication programs in California. For more detailed information contact Senior Biologist Supervisor Nick Villa who has had experience with both eradication programs at 916-358-2943, or their Conservation Education Office at 916-653-7664. 19) If you contact the Montana Dept of Fish Wildlife and Parks in Kalispell, Montana (see if Laney Hanzel is still there) he may have a story to tell you about an individual that keeps a population of his favorite fish in a private pond. Although I can't prove anything, this walleye fan has been suspected of planting fish in open defiance of state regulations. I'm not sure if open defiance counts as a malicious introduction. 20) As someone once wrote, anglers are the original "Johnny Pumpkinseeds". I would hazard a guess that every state fisheries department would have a story of some angler or group "improving" waters by unauthorized "stockings". But I believe I have seen more written references of this in the Pacific Northwest, particularly anglers stocking largemouth bass in waters being professionally managed for a cold water fishery. Not surprising, since it wasn't that long ago that many states dumped various species into lakes and ponds, just to see what might happen, with little thought given to impact on native species or the survivability of the species due to water temps, pH, etc. 21) I spent several years in the Peace Corps in Palau, a group of islands in Micronesia. I was told by some older Palauans that during WWII the Japanese introduced saltwater crocodiles collected in Indonesia or Malaysia into the mangrove swamps on Peleliu Island in the southern part of the island chain to discourage the Allies from landing troops on the islands. I am not sure whether the story was true or not but the crocs were a definite problem while I was there. 22) I can't remember the exact facts, but there were some specific threats of malicious introductions in the Galapagos last year (1996 or 1995). The locals wanted to protest against the invasion pleasure/tourists boats run under license by mainland operators. I think it concerned terrestrial organisms but am not sure. TRAFFIC would know. 23) I can pass along an anecdote, for what it's worth. An individual, of Tol Island, in Chuuk Lagoon, E. Caroline Islands, Micronesia, told me he saw person from the next island, Polle, over come to his island and release Bufo marianus (spelling?), the marine toad, on Tol, out of some kind of spite. This introduction isn't the only malicious one I have ever heard of, anecdotally---it was some kind of folklore on the beach in Hawaii in the 70's that mosquitoes originally were brought to Hawaii by a captain who was angry at the chief, and went (to Peru?), to bring a bucketful of wigglers to the islands. The first anecdote is more testable and more believable. 24) We had a borderline case, too. People introduced northern pike into a lake, Summit Lake, north of Prince George, BC (almost in the geographic centre of the province) on the Crooked River, presumably to improve fishing, but rumor suggested that the secondary aim was to undermine the Fisheries Branch and Conservation Officer service. It cost about $75,000 U.S. to do test nettings throughout the system for a year to determine that they had not become established. Summit Lake was on the fur trade route in B.C., as it is an easy portage into the Fraser River system. The Fraser supports a huge salmon fishery (one of the points of contention in the U.S. - Canada salmon disagreement). Well, northern pike carry the parasite Trienophorous crassus (I have probably miss-spelled that, and my reference is packed), which forms ribbon-like encysted forms in the flesh of fish. These are not very appealing in a commercial species, although to people they are not a problem (when cooked!). However, the economic impact could have been in the tens of millions per year if the fish and its parasites crossed over the continental divide. The country there is flat, and many streams have shared headwater wetlands, so the possibility was very real. 25) I cannot think of any instance where an introduction of an exotic fish was deemed a terrorist act. These have always been considered a result of an accident or ignorance. Seldom, however, have exotics ever proved beneficial to the receiving ecosystem. I suggest that you contact the Introduced Fishes Section of the American Fisheries Society (; these folks are the technical experts. If you wish to make an inquiry at the executive level, contact the AFS itself ( The AFS Executive Director is Paul Brouha and he would probably refer you to the Section people anyway. .........end of summary........