The simple solution is a die-off triggered from pesticide or industrial chemical use - not sure precisely where on the food chain the fish are but if they're sufficiently high up it's possible they're the only species that received a high enough dose to kill them.
Yeah but, a hundred thousand of them in one day? In one location? And just that one species? I don't anything about "drum fish", but the simple solution sounds fishy to me.
(Note: this rambles more than I'd like!)
The fact that a large number were killed
apparently simultaneously does in fact lead to some potential problems with the simplest solution. The large number, in a single location, and the one species part don't have as many (serious) problems.
Let's say some toxic chemical was dumped into the water at one site. Then you'd expect the die-off to be highly localized - downriver of that site only. Hence, a single location.
If the species is populous in that area and prefers that type of location (ie a stream or lake, that sort of thing) it's possible that large numbers of the fish would congregate there.
Now, instead assume that it's not a toxic chemical, but perhaps food contaminated with a toxic chemical. Smaller fish would congregate to a dump site, attracting predatory fish as well.
Now, if the drumfish are scavengers/ 'low on the food chain', then it's possible they were the primary/sole consumers of whatever was dumped, and thus they were the only ones that died. If the toxin is fast acting, then you'd likely see a situation similar to what has already been reported on. If it's slower-acting, you'd probably see more widespread dispersion of the die-off and potential some die-off in the predatory fish as well (from eating the drumfish).
If the drumfish are predatory, then it's possible the scavenging fish are their prey, and either the contaminated critters were all eaten, or they were not noticed in the dieoff. Or perhaps the concentration of toxin in their system was not enough to kill them, and the drumfish consumed sufficient quantities of it to make it lethal.
Now you can see where the "near simultaneous" part is causing problems. It implies - in either case - that most of the consumption was done in a very short time period.
The toxin argument and the disease argument both suffer from this problem - why did they all die so rapidly, in such a short time frame?
With a disease, however, if it's waterborne and infects the skin/scales/gill system, if it was somehow introduced to the water it would very, very quickly infect all the fish in the area. If it's fast acting or the fish aren't migrating much, you'd see a very localized die-off over a short time, assuming all fish experience approximately identical symptoms and disease development.
Disclaimer: I am not a biologist, chemist, environmental scientist, ecologist, or anything at all related to this.
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Topic: The Plagues Have Begun (Read 12019 times)