Not necessarily. The northern snakehead occurs northwards to at least the
middle and lower Amur drainage in eastern Russia, at about the same latitude
as Lake Winnipeg and James Bay, Canada. It would likely be tolerant of some
pretty doggone cool temperatures.
Berg (1965) notes that in the Lake Khanka drainage of Russia they are
relatively abundant in tributary mouths during the winter, that they reach a
maximum size of about 85 cm. They are summer spawners that spawn at age 2,
build detritus nests, and average 7300 eggs/ gravid female.
Most interestingly, Uchida and Fujimoto (1933, cited in Berg 1965) suggest
that O. argus requires atmospheric air to survive and can survive out of
water (presumably if kept moist) for 3-4 days at 10-15 deg C. Perhaps this
is the source of the claim that they can crawl about overland - but if they
require atmospheric air how do they deal with ice?
I would imagine that they would be able to withstand long periods w/o access
to surface air at low temperatures (like below ice at 4 deg C). If a silly
little map turtle can overwinter for 6 mos without a breath, I'd be really
amazed if a snakehead couldn't. More likely, they're just facultative
air-breathers that use it when they can.
There's a pretty good bibliography on snakeheads at:
http://www.fishace.demon.co.uk/snake/bibliogr.html
There's nothing in there about them eating pets and small children, being
able to bite through steel, being able to drink rotenone for breakfast, or
having plans to take over the world...
cheers,
Dave
-------
Berg, L.S., 1965. Freshwater fishes of the U.S.S.R. and adjacent countries.
volume 3, 4th edition. Israel Program for Scientific Translations Ltd,
Jerusalem. (Russian version published 1949 by Academy of Sciences of the
USSR, Zoological Institute, Moskow-Leningrad).
Uchida, K. and M. Fujimoto. 1933. Bulletin of the Fishery Experiment Station
of Chosen, Fusan. 3:89-91 (not seen but cited in Berg 1965).
-------
David A. Neely
Dept. of Biology, St. Louis University
St. Louis, MO 63103 USA
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