Crayfish in Crater Lake threaten newt population

[JReed]

Link to article:

Crayfish in Crater Lake threaten newt population - Email Blast - Klamath Herald and News

 

[sde]

Argh, that's too bad.
Though I rather doubt that Taricha granulosa mazamae is actually a valid subspecies. Similarly colored Taricha granulosa have been found in Gravina island, Alaska, and I have found individuals with similar coloration here in Washington. Apparently saliva was collected from T. g. mazamae for DNA analysis, and the results were supposed to be available in 2011. I can't seem to find it though.
Anyway, hopefully the figure out a way to remove the crayfish, though the task seems daunting.

 

[JReed]

Yes, I was really sad to read the article too. And the newt-crayfish battle is happening just 40 minutes away from where I live. I was reading some other articles describing how Taricha granulosa mazamae are much less toxic than their non-Crater Lake dwelling Taricha granulosa brethren, and that they likely lost much of their toxicity due to lack of normal predation ( Crater Lake is a massive volcanic crater that is very steep and physically isolated). Well, thanks to human crayfish introductions, the predation situation has completely changed. And it looks as if these unique, relatively non toxic T grans are losing the battle. So sad.

 

[sde]

Yes, I was really sad to read the article too. And the newt-crayfish battle is happening just 40 minutes away from where I live. I was reading some other articles describing how Taricha granulosa mazamae are much less toxic than their non-Crater Lake dwelling Taricha granulosa brethren, and that they likely lost much of their toxicity due to lack of normal predation ( Crater Lake is a massive volcanic crater that is very steep and physically isolated). Well, thanks to human crayfish introductions, the predation situation has completely changed. And it looks as if these unique, relatively non toxic T grans are losing the battle. So sad.

From a bit of research it looks like they introduced the fish into the lake for recreational value. Then added the crayfish as food for the trout. Just another example that when you tamper with natural ecosystems problems can occur.
Yes, the article states that they are less toxic, probably because of lack of predation. I went to crater lake last summer, and it was a surprising landscape. The area directly surrounding the lake is a lot dryer than I would have expected ( though I did go in the summer ). Does Taricha granulosa mazamae spend all of its time in the water? Or does it have the seasonal cycle that most Taricha granulosa do? Outside the water it doesn't seem like very suitable habitat. Sorry, that last bit was a bit off topic.

 

[Coastal Groovin]

If 35 traps were not enough to effect crayfish populations then try 135 traps.

 

[frogman]

Now the newts have this and skin fungus coming on them, this may be the dawn of the newtpocalypse.

 

[otolith]

If 35 traps were not enough to effect crayfish populations then try 135 traps.

I thought the same thing. 35 Traps is a pretty pitiful "eradication attempt". They could put some sort of incentive on a recreational fishery. Along the lines of no limit, no limit on traps etc.

 

[JReed]

Seth, I agree with you. The Crater Lake surrounding area seems, at first glance, to be much too dry for a wet-loving species like Taricha granulosa. When I first heard that Taricha granulosa lived at Crater Lake I could not figure out how they would survive there (most wild Taricha granulosa that I have seen live in rainy, soggy places like the Williamette Valley, Oregon). But I suppose the dryness issue partly explains why the Crater Lake population is so isolated. The dry environment may help keep the populations isolated? ( other populations can't get "in") I personally guess, that the Crater lake newts spend much of their life cycle in the lake, larvae, sub-adults and adults. Maybe somebody else can chime in on this? It is an interesting question.

As to the comment by "Coastal Groovin" that people should increase the number of crayfish traps in the lake ( and maybe add the traps deeper in the lake too?) this seems like an idea to me. Crayfish are human edible food. Why not "fish" the crayfish more aggressively to give the Crater lake newts a better fighting chance?

 

[sde]

But I suppose the dryness issue partly explains why the Crater Lake population is so isolated. The dry environment may help keep the populations isolated? ( other populations can't get "in")

Yes that is possible, but I wonder how they got there in the first place? Maybe before the volcano erupted it wasn't such a dry arid place, so there could have been a good population of them. But maybe after it erupted that changed, and the only newt survivors were the ones that found there way into the lake?

I personally guess, that the Crater lake newts spend much of their life cycle in the lake, larvae, sub-adults and adults. Maybe somebody else can chime in on this? It is an interesting question.

I would think they are pretty forced to stay in actually, I mean it is so steep and dry around them with very few suitable seeming areas for them to dwell if they were to venture out of the water. But there was one wooded area at the one side and on the island that might have enough shade for them to come out I suppose.

 

[otolith]

It seems very possible to me that the T. granulosa at Crater Lake have a terrestrial phase even though it is dry and hot much of the year. I always figured they just aestivated during the dry season. T. rivularis live in areas that are regularly 100F+ during the summer with no rain from May-October. T. torosa are able to thrive in parts of California that average 16" or less of rain a year.

 

[JReed]

Yes, and both "newtpocalypse" issues, the invasive crayfish and the invasive fungus, were caused by humans.

 

[Coastal Groovin]

There is no way to blame humans for the spread of the fungus. I'm willing to bet my house that migratory waterfall fowl do a great job at spreading the fungus hundreds and thousands of miles without any human help.

 

[Azhael]

There is no way to blame humans for the spread of the fungus. I'm willing to bet my house that migratory waterfall fowl do a great job at spreading the fungus hundreds and thousands of miles without any human help.

Yes, Batrachochytrium was taken from south Africa to centralamerica, europe, etc, by birds... but only in the last few decades....and they even managed to spread the fungus into private collections!
Not by people spreading Xenopus across the globe, oh no, that's completely out of the question, it was the birds and only the birds

 

[Stupot1610]

There is no way to blame humans for the spread of the fungus. I'm willing to bet my house that migratory waterfall fowl do a great job at spreading the fungus hundreds and thousands of miles without any human help.

The way I see it is that humans are almost entirely to blame. Sure, birds will carry it from place to place but ultimately it is the pet trade we have to blame. Species that carry the fungus have been distributed all over the world and sold to people who get bored of them after a few weeks and eventually end up releasing them. This is when the fungus comes into contact with wild amphibians and causes such great problems.

Stuart

 

[Coastal Groovin]

Xenopus has been on every continent longer than most of us have been alive. Trying to blame them for suddenly for spreading a fungus laughable. How about all the plants that have been shipped from continent to continent. I'm sure no one is testing that soil. So many ways to spread it, plants, fresh produce, migratory birds, the bottom of your hiking boots, or boat ballasts. I find pin pointing to any one animal or one way as impossible.

 

[Azhael]

So we have multiple potential routes, all of which except one, the most far-fetched of all involving cross-continental transportation by birds, are the product of our activities, and you are convince that's the one to blame and that we are definitely not responsible. Sounds legit.