This is the comment of snakeheads.org on the proposed rule for banning snakeheads which was brought forth by the Fish and Wildlife Service to be discussed until 26th of August 2002. This comment was accepted by the this US-governmental agency.
snakeheads.org runs the world's largest website on snakeheads non-commercially. In respect to Channidae, it promotes information from many areas as for example: science, ichthyology (natural history, taxonomy, ...), aquaristic, ecology, and aquaculture/food.
The runners of snakeheads.org are members in two international associations for Labyrinth fish and do run an international working-group on Channa, which is held regularly. A small network with ichthyologist of the world is maintained.
In reaction towards the «Frankenfish», the Proposed Rule argues to ban all Channa species in the USA. We think it is disproportional to ban all species.
You have established a net of arguments analyzing the possible dangers of Channidae in the US. But this net of possible dangers blurs certain facts, which we want to list below and from which we cannot see why it is necessary to prohibit all Channa species in the USA. Instead, we claim that most of the dangers you have listed can be nearly fully reduced by the prohibition of maximum five species: C. argus, C. marulius, C. marulioides, C. micropeltes, and C. striata. In the following, we try to present our arguments in favor of the other 23 species not to be prohibited nationally from aquarium trade and keeping.
One of these blurred facts is the size of the 28 mentioned Channa species in respect to the establishment of Channa in the US as mentioned by your article.
Two species, which happened to get established, are of considerable size (C. argus, C. marulius). And there are in total only four species, which gain this size (these other two are: C. marulioides , C. micropeltes). These species are sometimes called tank busters - what they really are.
You mention reports on attacks of C. micropeltes against humans, but you do not cite one single reference. We maintain probably the world's largest database for Channa bibliographic references. We have collected more than 1500 references of which we have assembled for about 50% percent. We have never read of these reports but only one ( Tweedie, 1949). This report talks about a fish defending its hatchlings. We do not think that such a behavior could support your claim that Channa are dangerous for humans. Most creatures on earth do defend their descendants.
When you list the ecological dangers in respect to the eradication of indigenous species as well as to the lack of natural enemies, these four large species can come into consideration (precondition: they find a fitting thermal environment, which is not necessarily so, see below).
In opposite to the large species, dwarf size Channa (five species much below 20 cm: C. bleheri; C. gachua, C. harcourtbutleri, C. orientalis. C. spec Assam) cannot be considered to eradicate life in a habitat. Snakehead.org knows no source where this fact is reported. The Proposed rule mentions 136 aquatic endangered species (which must be saved from eradication!). If you prohibited C. orientalis for example you would not help those species because it is reported that the gut contents of C. orientalis consists of 86% terrestrial insects (Pethiyagoda, 1991; p. 282). This report talks about a fish defending its hatchlings. We do not think that such a behavior could support your claim that Channa are dangerous for humans. Most creatures on earth do defend their descendants.
Arguing against your (implicit) claim that Channa would have no ecological enemies: We have a report on the occurrence of a killing of a C. micropeltes (8 inch) by a 12 inch bowfin (Amia calva) - see FAQs
All but eight species can be categorized as medium-sized Channa. The dangers and occurrences listed in the Proposed rules are confined only to three of these 20 medium species, i.e. C. striata , and C. punctata , am C. maculata . You mention C. striata as already established in Hawaii, and as a valued food fish. You also mention it on respect to the disease EUS with which occurs in aquaculture since the 1980s. C. punctata is mentioned also in respect to EUS . The third species is also cultured as food fish mostly in Taiwan and Mainland China: C. maculata (see here for further information). You have mentioned it because of its rapid spreading in the non-indigenous waters of Japan, which nearly has the same thermal climate as its habitat (South-China). And since C. punctata is cultured only for the internal market in India (it is not listed in the FAO fisheries statistics as far as we know - see here), there is only one species that threatens the US natural resources C. striata.
Another argument for the dangerousness of Channidae - and one of the facts why the Crofton C. argus has become so feared - is its ability of overland migration and being able to stay out of the water for days. The author of your paper fears that the loss of the fish during its transport could establish Channa. Indeed, Channa are well known for the behavior of overland migration. Due to Cuvier did mention that Theophrastus already had reported of a fish in India being able to walk overland. Cuvier attributes a Channa species to this fish. Hamilton Buchanan reported of Europeans, which thought of Channa coming from the sky with rain. Fact is, the most common form of death of Channa is their tendency of jumping out of the tank and dying within hours. One might find them still living on the floor, but we never have heard or experienced that one would have survived its journey on the floor (For reports of deaths and warnings to cover the tank: see our FAQs. Furthermore, some Channa ichthyologists (Ng, 1990 Ng, 1990) states the speculation, that the missing of the ventral fins at some species is due to its inability of overland migration. We want to indicate that it is necessary of very special circumstances to survive overland for a longer time. And because of that one will not find a C. argus in Crofton walking on land!
We have got the impression that Crofton has increased the speed (the need?) to formulate a ban of Channidae.
Another blurring of facts occurs in respect to the danger of establishing and spreading of Channa in nonindigenous waters. This is one of the main arguments in favor of the prohibition of Channa. You list the case of C. striata spreading in Hawaii since the 19th century. In fact, in 100 years it could establish itself only in one area. This argument counts even more when you take into account that Hawaii offers living conditions, which are equal to those of this species habitat. In addition to that, there are also reports of unsuccessful governmental tries to introduce Channa to nonindigenous waters. Namely, so are reports of C. argus from Czechoslovakia ( Frank, 1970) and C. striata from the Fiji-Islands ( Andrews, 1985). In this light, to talk of dangers that Channa could spread from Florida to Canada sounds not like an unprejudiced scientific estimation of facts.
The last example for the blurring of facts, which we want to list here, is the adaptability of the Channidae in respect to the water temperature. You list a range between 0° C and 30° C. This range is tolerated by C. argus. In fact no other Channa species could tolerate this lower end. C. argus is the one species, which can exist, in such a cold thermal climate. There are other species, which have their habitat in the southern range of the Himalayas (Assam, Nepal, Birma, a. o.). The melting water from there comes down in the Brahmaputra and other streams. Reports show, that those fishes like colder temperatures for a while, but we do have reports which can show that species coming from there do not tolerate a water temperature below 12° C. (In German: Channa AG). How should these other 27 Channa species be able to spread up to Canada? All the arguments work like this. You mention (mostly C. argus) a species, which has a certain characteristics, and then you infer it to all other species implicitly no matter it makes sense or not. How else could you find supporting arguments to prohibit the genus Channidae in total? We disapprove this disproportional approach.
snakeheads.org cannot but to state that a certain probability of Channa species as ecological intruder agents. We cannot hide away from this fact (the introduction of C. striata in Madagascar and other reports from Papua New Guinea as well as those of Central Asia would proof us wrong). The danger to which the USA and its fauna are exposed to is compared to other western countries higher because of two reasons: Some Channa species (C. argus, C. striata) are valued food fishes among some Asian inhabitants of the USA. And since their hardiness, it is easy to keep them alive and therefore fresh, which makes them valuable even more. Second, the US aquarium trade mostly imports some of the four large Channa species (namely C. micropeltes, C. marulius ).
Taking into account the interest of the US government to guard its nature resources and the facts on Channidae as presented above, we think that the ecological danger stemming from this family of species could get reduced to a very large percentage through the measurement to prohibit 5 species. These are the large species C. micropeltes, C. marulius, C. marulioides, C. argus, as well as the smaller but tough species C. striata. Life trade of food fish likes C. striata and C. argus could get forbidden, thus eradicating the root cause of Channa establishment in non-indigenous waters. The prohibition of the large species in aquarium trade does it make impossible that those grow out the aquarists' tank (as happened in Crofton) and those do not get set out by irresponsible citizens. The aquaristic keeping of the other species of Channa makes it still possible to discover more biological secrets as happened to G. Ettrich who discovered some Channa species to be mouthbrooders ( Ettrich, 1982; English version here). One day, if the destruction of the rain forests all over the world goes on unhindered, we will be happy to keep species alive by systematic breeding methods. Serious aquarists could support this by exploring the keeping and breeding of exotic species.
Andrews, S. 1985; Aquatic species introduced to Fiji. Domodomo 3(2):67-82.
Ettrich, G. Das Schlangenkopffisch-Männchen entpuppte sich als Maulbrüter. AQUARIEN MAGAZIN pp 651-653.
Frank, S. Acclimatization experiments with Amur snakehead, Ophiocephalus argus warpachowskii Berg,1909. VESTNIK CESKOSLOVENSKE SPOLECNOSTI ZOOLOGICKE. Cislo 4. pp. 277- 283.
Ng, K.L.P. and Lim, K.K.P. Snakeheads (Pisces:Channidae): Natural history, biology and economic importance.
Pethiyagoda, R. 1991; Freshwater fishes of Sri Lanka. The Wildlife Heritage Trust of Sri Lanka 1-362.
Tweedie, M.W.F. 1949; Notes on Malayan freshwater fishes. Bulletin Raffles Museum. Vol. 21, pp. 97-105.
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