RAUK - Archived Forum - Great-crested newts and fish

All the litereature tells that GCNs and fish do not mix.

Why is it then that many of the best GCN ponds in Purbeck and surrounding area also contain good pops of carp.

Is the threat species specific?, rudd, roach. etc.

Tony

I know little about fish- but I suspect the smaller, more carnivorous species are worse.

Sticklebacks in particular seen very bad for newts- I've seen them eating vast amounts of smooth and palmate newt larvae in garden ponds, and I expect that small crested newt larvae would be eaten just as readily.

I can't image that large carp would hunt newt larvae, and I would expect them to be put off by the venom of adult cresteds.

I would have thought that the main crested problem with fish would be the strategy of young cresteds to hunt and 'hang' in open water, this makes them vulnerable to approaching fish?

I'm not so sure that carp in low densities with an abundance of other natural food would be a problem. But in high densities where food is at a premium carp will eat just about anything. Rudd, I feel would be better geared up to eating young cresteds as they are hunting insects from mid-water upwards to the surface. So I guess for there to be a problem between fish and newts then fish densities, natural food abundance and general cover sub-surface would be relevant factors.

Tony,

At the pond I went to on my second training night for my GCN licence Will Atkins of LEHART pointed out 71 adult Great Crested Newts, next to this is another pond, this is the first you come to when entering the woods.

Will mentioned that he had never once seen a GCN in this pond, and was convinced that this is because people put fish in it and somehow the GCN know to avoid it. Sure enough when we looked that night, only yards from the other pond, not a single GCN but plenty of Smooth Newts.

I was just updating the Natterjack toad ID page with some new pictures from David and adding a bit of text. Beebee and Griffiths mention that Natterjacks do well in some large ponds where in particular carp and perch are present, as they keep invert predators down, whilst finding Natterjack tadpoles distasteful, maybe the carp at Purbeck are a benefit to GCN in this way also?

Gemma-

I'm intrigued by this pond yards from the other crested pond, but with none in.

When I used to live in Cambridgeshire, in an area with loads of cresteds, they would appear in almost any pond. Only the best ponds had any reasonable numbers, but I don't think I ever found an accessible pond that never had any. 'Unsuitable' ponds ranged from a brick-built sheep dip (about 4x2m, only 15cm water), a cattle watering pond (just a shallow muddy hole), and a 100% shaded pond full of dead leaves, to an enormous clay pit that had been stocked with fish (including vast numbers of perch).

It would be interesting to know why they avoid the pond you mention- maybe they all leave the good pond by the other direction? I wonder if they ever go through the bad pond to reach the good one, or never even enter it (walk around it)?

Hi Caleb,

It's quite fascinating, the site is a small NNR, that has a little management from a interested local in the winter.

There is yet another pond, this is very similar to the one where the GCN are totally absent and close by - this is where we spotted a neotenous smooth newt, it contained a few GCN as expected. Will is convinced the GCN know to avoid the pond they are absent from and has surveyed the site many times since the newts were introduced as part of a translocation back in 1996 and has never once seen a GCN in the fishy pond.

The 3 ponds are all similar, gentle slopes with easy access, though the main pond is larger and deeper and proportionally less weedy.

Hi all sorry new to this but where i live there is quite a few gcn's and palmate too! but the powers that be a wrecking this soon as lots of the ponds around here have/are being filled in to make way for houses! as i understand it i am not allowed to move them for legal reasons? but i feel moving may also increase the chance of infections too? sorry don't know much on the subject!

i live in the Chester area so if anyone knows of a safe haven and knows the legal route i will be more than willing to show all the sites!

will view the forum soon! thank's

Woody- you might want to contact your local reptile and amphibian recorder- they would be interested to know details of any GCN sites in your area. There's a list of local recorders at

http://www.froglife.fsnet.co.uk/RecorderFrame.htm

Hope that helps!

I've seen one, or two ponds where newts have mixed with fish & they tended to do okay as i think they kept to breeding in very shallow & very reedy areas where maybe the newt larvae were more inaccessable & could also hide easier. Certainly in general though newts & fish usually don't mix. The best GCN pond i know of is fortunate in annually drying out by each mid' to late summer & so fish (say, eggs brought in on weed of waterfowls feet)  can't really establish there.

Just from things i've myself seen i'm sure newts normally have a maternal sense of responsibility when they check out ponds for fish. My pond was originally a fish pond for its first couple of years & i'd notice a few local Smooth newts would come & drop in & check the pond out for a day, or two, but then they'd vacate it as obviously not being suitable for them to consider breeding in. Almost as soon as i gave my fish away & made my pond a purely wildlife one newts moved in & stayed & a dozen years later newts now thrive in there, including sometimes the odd few visiting GCN's, plus i introduced Palmates eight years ago & they're doing great too, & there's Common frogs (extract spawn each y'r & rear safe from voracious newts) & Common toads are plentiful.