Shocking as it may be to anyone with even a passing awareness of conservation issues, tiger salamander larvae (Ambystoma tigrinum) are still widely used as fishing bait throughout much of the USA. Run through with hooks while alive, the 6-10 inch amphibians are wildly popular with anglers seeking bass, pickerel and other fishes.
Disease and the Bait Trade
Recently (April, 2009), biologists at the National Science Foundation announced that a significant percentage of larvae in the bait trade have tested positive for the deadly Chytrid fungus Batrachochytrium dendrobatidis. This fungus has decimated amphibian populations on nearly every continent, and is responsible for the extinctions of local populations and, most likely, entire species.
Herpetologists are working feverishly to control its spread, but are as yet unable to understand why the fungus has become such a devastating problem in recent years. Often, the only hope for amphibians in its path is captivity – colleagues of mine recently collected an entire population of Panamanian golden frogs, but the long-term outlook is quite dim.
Virulent ranaviruses, which quickly kill many amphibians, have also been identified in larvae sold in bait shops in Arizona, Colorado and New Mexico.
As if the all this were not enough, the release of bait trade salamanders has resulted in the hybridization of critically endangered California tiger salamander populations (released barred tiger salamanders mated with the California subspecies).
Hybridization threatens survival by altering critical components of the genome. For example, when various subspecies of ibex (mountain goats) were released together in Spain, the resulting hybrids gave birth during the winter, and the population became extinct.
Partners for Reptile and Amphibian Conservation http://www.parcplace.org/, an organization of professional herpetologists and interested citizens, supports numerous research programs. Please be in contact to learn more about this issue and their many interesting volunteer opportunities.
Next time I’ll discuss other threats to tiger salamanders, their conservation status, and problems regarding food market bullfrogs.
Please see my book Newts and Salamanders for information on the natural history and captive care of tiger salamanders and their relatives.
Image referenced from morguefile.