84 replies to this topic

[computerlog]

Juls I’m well aware of what freshwater natives we have, I was more interested in seeing if those who are removing koi to protect them knew.

From the sounds of it, where people are targeting to remove koi (council dams and ponds) will not contain any of these natives which need protecting. There are areas in Perth which would benefit from the removal of koi but man made ponds in parks are not them.

[ice]

I meant to type getting rid of the ferals not the natives, thats my bad.

I personally have removed feral carp from a few different spots that I can guarantee are suitable habitat for native frogs/fish and crustaceans, i've even seen them there. Probably not for too much longer though. Carp are well known to eat just about anything and this does include tadpoles and frog eggs and even baby carp, i've seen them eat them before and you only need to ask Nick about his backyard pond and what happened to his taddies in there.

Carp are also well known for completely destroying fish habitat so perhaps that is why there are only carp and only ever will be while they are there.

I totally agree with you about the gambusia and redfin situation though, I don't think enough is being done to eradicate them and as for stocking trout don't get me started. Personally I try to go fishing for redfin as much as I possibly can whenever I'm down south. They are delicious.

How would it be possible though to eradicate the entire population of gambusia in our waters? That is a truly monster task.

Catching a few feral koi around the place however is not difficult and is a hell of a lot of fun, might as well embrace it instead of trying to find the negatives.

[computerlog]

I’m not saying I’m against their removal but it should at least be done in areas where they do present a threat such as in the areas you’ve seen.

Ponds and lakes which have never and will never contain natives don’t seem like appropriate places to target. There’s a small pond down the road from me near a retirement village filled with koi, made by the council around 6 years ago. Many of the people living in the retirement villages near it can be seen feeding the koi daily. Would it be justified for me to fish the koi out under the false pretence of protecting natives while those who enjoy their presence lose out?

If only catching gambusia was as fun as redfin and koi, maybe fisheries should introduce something to prey on the gambusia? They’ve done a brilliant job of wiping out natives down south so far gambusia shouldn’t be too hard.

[ice]

Haha don't joke about it, it'll be the cane toad all over again.

I think areas like you said and places that are not connected to and never will be connected to natural water ways are PROBABLY safe to leave how they are. However... floods and birds can always play a part in live fish transport, as can uneducated public... That being said I think any and all ferals should really be removed, we cant go playing favourites on areas or people. A feral is a feral and regardless of where it is there is still a chance it would get into a natural water way and run amok.

The only flaw in that is the people taking them home might be uneducated, one would hope not. Although I suppose that's how most of them get there in the first place...

[computerlog]

Completely agree mate and there's also the need to consider the spread of diseases which could impact on natives.

While I personally could never destroy a koi removed from local waterways, I do think it is necessary if those doing so are genuine about protecting natives. They could start they're own charlie carp, sure there wouldn't be any left besides those in private ponds within a few years and everyone could enjoy the public ponds and lakes stocked up with nothing but gambusia.

wonder if gambusia taste any good? could be the next whitebait, anyone keen to try some?

[dave06]

Juls I’m well aware of what freshwater natives we have, I was more interested in seeing if those who are removing koi to protect them knew.

From the sounds of it, where people are targeting to remove koi (council dams and ponds) will not contain any of these natives which need protecting. There are areas in Perth which would benefit from the removal of koi but man made ponds in parks are not them.

Introduced fish are not just being removed under the premise of 'protecting native species' but also to protect biodiversity.
As Im sure most of you are aware, koi and carp have a significant negative impact on the water body - eutrophication, turbity and negative impact on biodiversity as a whole. Even if no native fish are present in man-made lakes, removing noxious introduced fish can allow for the reintroduction or eventual return of native plants, invertibrates and animals. Furthermore the health of the ecosystem will dramatically improve.

Councils go to great lengths and use a huge amount of resources to try and create 'natural looking' man-made lakes. Pinnaroo is a good case study. The main lake was once concrete pond, a few years ago they did a pretty good job of attempting to create a natural wetland/lake, extensively planted etc. Only to leave the carp/koi in the lake. The presence of them is obvoius, they undermine the reeds, to the point where they fall over and rot away in the water. I am sure they would also have an impact on a lot of the plants/animals that attempt to settle there.

I have witnessed first hand 'do-gooders' catching carp from a shrinking lake over summer, under the premise of 'rescuing' them, intending to release them into Lake Monger.
If the best we can come up with is that these introduced pests look pretty and elderly people enjoy feeding them, this is counterproductive to our message. People develop an emotional attachment to these fish and instead they are promoted and the few education programs in place are ineffective.

We preach "dont release fish into waterways etc" but do nothing to remove the fish that are already there ?

Just some thoughts
Dave

[bigjohnnofish]

How would it be possible though to eradicate the entire population of gambusia in our waters? That is a truly monster task.

the only possible way of wiping out gambusia would be to introduce a sterilized predator which has a limited life span... maybe some killi fish????

the predator would wipe out gambusia in its water way then die out itself over time....

any ideas on what species would be good???

[ice]

Sounds good but imagine how many more little natives would get eaten in the process also. I think a virus that targets them specifically like what they did with the rabbits. Biological warfare

[bigjohnnofish]

Sounds good but imagine how many more little natives would get eaten in the process also. I think a virus that targets them specifically like what they did with the rabbits. Biological warfare

well the rabbit viruses didnt work cause we still have heaps of the little fuggers!!!!

[Kleinz]

The Calicivirus wiped out upwards of 96% of the rabbits, but that was a few years ago and they breed like, well, rabbits...

The myxo strains had to be continually tinkered with to get around developed resistances.

The Calicivirus was never an intentional release, or they might have followed it up too. A slightly different strain every few years would do the trick.

Interestingly, in the few years we had of very few rabbits they worked out that rabbits are indirectly killing off the black cockatoos.


I reckon cane toads might give the gambusia a run for their money

Edited by Kleinz, 22 October 2011 - 06:52 PM.

[bigjohnnofish]

Interestingly, in the few years we had of very few rabbits they worked out that rabbits are indirectly killing off the black cockatoos.

hmmm interesting - got any more info as to what links the rabbits/black cockies together ???

[Kleinz]

The Carnaby's cockies rely on seeds in the cones of a few trees similar to sheoaks. The trees are not long lived. New ones are unable to grow as they are invariably nibbled to death while seedlings by rabbits. As the older trees die out and are not replaced, the food supply shrinks. The cockies either starve or work the orchards and get shot.

The calicivirus outbreak so reduced the rabbit population for several years that new trees were able to grow for the first time in decades. By the time the rabbits returned in numbers, the trees were tall enough that the rabbits could not kill them. Numbers improved and populations returned to a few areas.

It was pretty instructive. Everyone knew that rabbits could really screw things up for competing herbivores, but noone had thought of the cockies.


Anyway, all a bit OT, really.

[Riggers]

I'm really glad to see that people are talking about this because after a few more phone calls and research I've come up with a little more info.

Yes at first it was a bit of fun until I started looking into the reasons why the fish are there in the first place. Obviously these suburban ponds we are talking about are man made and are taken care of by local councils, it wasn't really a surprise when I found out there are certain councils that will stock a lake/pond with koi or carp just because people are uninformed about native species or alternatives for the waterbody.. There is one particular park that I have been to that has numerous large signs stating the removal of native flora and fauna is illegal.. They are in direct conflict by then having introduced species in there. it was unfortunate that all I saw was 1 turtle and around a dozen introduced fish.. What happened to the natives?

I am aware that these man made waterbodies would have never had native species in them, what I was suggesting is that instead of destructive fish such as carp/koi I'd like to go to a local waterway and see turtles, frogs, shrimp and crustaceans as well as other plants that are native to the area. This may take a little research to find out what species are native to certain areas but could be a better solution.

I think that's all I've got for now I'm chatting with my local council this week again so I'll let you know how it goes

Cheers
Nick

[scottyhooton]

good work nick , keep it up

[Silks]

This is incredibly interesting! Hope you have some joy with the local govt and the respective depts, Riggers!

By the by, the City of Canning referred me to the Swan River Trust and the Dept of Fisheries FISHWATCH, for all inquires about 'guidelines or instructions on catching feral fish in the waterways, ponds, drains and rivers around Canning'.
http://www.swanriver..._feral_fish.pdf

There are masses of interconnected waterways in Canning, drains, ponds and the river itself. I have seen Koi, Carp, cichlids and all sorts of ferals while walking. I'd love to remove them but don't fancy the jumped up council workers giving me grief over it lol!

[computerlog]

Hi Nick

The fact that you're willing to spend your free time on this is commendable, glad to see your doing the research required since it really is a difficult task restoring water bodies to their original state. If you'd like I can send you any relevant journal articles I come across they're much more useful than the limited information published by fisheries. Just pm me an email and when I have some free time I'll get onto it.

If anyone else is interested in helping restore local waterways Conservation Volunteers can always use some extra hands. It's not the most stimulating work (weeding, mulching and digging) but it focuses on areas where there has been some previous investment in restoration. Plus there are always some interesting backpackers to make things a bit more enjoyable. Be nice to see some members there since there is generally a very low number of Australian citizens'’volunteering.

Few things coming up, not as fun as fishing but worthwhile none the less:

http://cvops.cva.org...projectId=45223
http://cvops.cva.org...projectId=44862
http://cvops.cva.org...projectId=42221

If anyone's looking for a good place to target, above Kent St weir is good as there's been a decent number of goldfish seen/caught around there over the last few years and that's an area directly impacting on the river system.

Edited by computerlog, 26 October 2011 - 05:43 AM.

[computerlog]

Just a side note while I'm at it, while I know I advocated the destroying of feral fish I’d hate to see them end up like the blowies with piles of dead fish all over the place. If Nick or any others removing them could rather offer them up for free on here for members to home that would assist in alleviating any concerns that community members may have over seeing them destroyed. If needed I could hold some fish until final homes could be found.

[Evil_Boof]

Just a side note while I'm at it, while I know I advocated the destroying of feral fish I’d hate to see them end up like the blowies with piles of dead fish all over the place. If Nick or any others removing them could rather offer them up for free on here for members to home that would assist in alleviating any concerns that community members may have over seeing them destroyed. If needed I could hold some fish until final homes could be found.

its all well and good trying to do this.. and i do think cruelty to fish is still cruelty. but these fish need to die. if homes can be found, awesome. if not, i wouldnt worry about it too much..

these fish gotta go, and if they are dead, that means no more breeding for that fish, and no more idiots dumping fish they dont want into waterways

Edited by Evil_Boof, 26 October 2011 - 07:42 AM.

[Bickley]

As Nick and I have already discussed my old boy has heaps of ponds that can be used for rehousing. This would only be a temporary solution as there's only so much we can stock the ponds but in saying that these are not your typical sized ponds either

Edited by Bickley, 26 October 2011 - 01:18 PM.

[bigjohnnofish]

As Nick and I have already discussed my old boy has heaps of ponds that can be used for rehousing. This would only be a temporary solution as there's only so much we can stock the ponds but in saying that these are not your typical sized ponds either

if you get over stocked treat them for parasites and sell them as feeders...... my rtc practises magic... makes fish disappear all the time!!! lol