Giant salamander pests?

There was an interesting story in a local newspaper a few days back about giant salamanders, which are protected here in Japan as Natural Monuments, causing problems in the upper reaches of the Kamo River that runs down to and through the city of Kyoto. In addition to gorging on nursery-raised indigenous Ayu (sweetfish) upon their release into the river for recreational fishing, the salamanders have been biting the hands of anglers who reach into the water to grab their Ayu -- at least 4 cases in the last 3 years.

A cooperative that manages fishing along that part of the river complained that if the problem continues, it will lose customers (nearly all fishing in Japan's rivers and other inland waters is under control of such cooperatives, which earn money by issuing fishing licenses in return for stocking and maintaining the waters in their territories).

Anyway, every spring for the past decade, when Ayu are released into the river at the start of the fishing season, several salamanders have congregated at the release spot for a feast.

Also, during the fishing season, some have been bold enough to break into fishing cases containing "Tomozuri-Ayu" and eat up all the fish inside. Tomozuri-ayu, by the way, are live Ayu used by anglers to provoke Ayu in the river, which are highly territorial, into attacking them when they enter already proclaimed territory (when an Ayu attacks a Tomozuri Ayu, it gets hooked on dropper hooks placed in the ventral fin and behind the tail).

The head of the fisheries cooperative was quoted in this article as saying, ''They (the giant salamanders) are undoubtedly eating a lot of Ayu, and it would be terrible if a child playing in the river were to be bitten by one.'' He said the number of giant salamanders in the area has been increasing, and called on authorities to rectify the situation before the next fishing season opens.

A Kyoto University expert on amphibians was quoted as saying it's not the case that the number of giant salamanders has suddenly increased, though they may have shifted their location in the river due to environmental degradation in their original habitat further upstream. He said a problem is that there is insufficient data to ascertain numbers, and urged authorities do some serious surveying in light of the current situation.

Here's the pic that accompanied the article in the Japanese-language edition of the Kyoto Shimbun.


(Source: http://www.kyoto-np.co.jp/kp/topics/2003nov/05/W20031105MWE1K100000032.html

I volunteer to do some surveying.

The box in the pic, does it contain Tomozuri-ayu?

Ralf

Heya Ralf. When I posted a link to that article on a Japanese-language discussion board for sal enthusiasts, a couple people jokingly offered to help out by adopting some of the problem sals. Too bad though, that would be illegal here

The caption that goes with that pic just says it's of a giant salamander that "has approached an angler's case containing Ayu."

I thought the information about Tomozuri-ayu would interest you in particular, being an angler and fish buff and all. I was reading that an Ayu whose territory is encroached upon will violently fling itself at the intruder, and that the anglers exploit this trait. Here's an illustration of pic of a Tomozuri-ayu:

Very interesting, Tim.
To be honest, I am quite ignorant when it comes to angling. I usually rely on other methods of fish-catching.
I have heard of similar methods of attracting fish for catching from Africa and South-East Asia.

Ralf

i think its rather intelligent of the sals to go after the easy food. i mean, would you rather slave away in the kitchen all day to make a meal, or go to mcdonalds? driving over to mcdonalds sounds a lot easier to me!