Fishing Victoria Forum

Mutley and Scruffy wrote:Are you sure it wouldn't lead to the same population of carp, yet a smaller average size? Just a thought with my limited knowledge! After all, I'm not a marine biologist!
cheers
Jim

i've been fishing a certain reservoir that has a well established population of roach for years. interestingly enough, i've never caught a single juvenile carp there, the smallest one was around 3 pounds.

Bob

It may be that in that particular reservoir conditions are not ideal for carp reproduction - hence the roach having the upper hand. Without identifying the dam concerned I can't comment further.

Earlier you suggested that a large variety of fish as competitors may be responsible for keeping carp numbers in the UK in check. In the Murray-Darling Basin there is (or was) at least as great a variety of competitors as in the UK. The explosion of carp which took place here may have been due to in part the environment being degraded and the reproduction of native fish competitors/predators being compromised.

The story is far more complex than what most people realise.

First, European carp are not native to the UK and Europe but are native to the Manchuria area of China. So they are in fact an Asian carp unlike roach, tench and rudd which are genuinely European. They arrived in Europe via Rome as early as the seventh century and were introduced to England about 1496.

European carp have been introduced to Australia on multiple occasions many years ago: Tasmania c1858, near Canberra c1870 and into the Sydney area and the central Murrumbidgee River in 1907. The result of all of these introductions resulted in small populations becoming established that did not cause the problems seen in recent decades.

In 1959 the Victorian Fisheries & Game Department received an application from a farmer near Boolara in Gippsland to farm European carp. They had already been imported from overseas and were a commercial strain developed for farming - at that point in time there wasn't any effective legislation preventing their import. His application to farm them was refused by the Director of the Department Alf Butcher who had seen first hand the serious effects of carp introduced into American waterways in the 1950s. Butcher's refusal was overturned on legal appeal. Butcher then lobbied the Victorian politicians to get the necessary powers to block the supply and spread of carp. Eventually he got the authority but in the mean time carp had been sold to farmers through Gippsland and stocked into farm dams. The Fisheries & Game Department then initiated a destruction program to try to get rid of them.

Alf Butcher contacted the NSW Fisheries Department asking that they ban the stocking of European carp in that state - and was treated with derision. The NSW people argued that European carp had been in their rivers for a long time without causing any problems. From some of the people involved at the time I was told that the Victorians were the butt of jokes in trying to control a phantom carp menace.

It is believed that carp from the Boolara farm went to several locations in the Murray-Darling Basin c1964. One location know with certainty is Lake Hawthorne near Mildura. They turned up in the Murray in 1968 and the rest is history.

The carp in the waterways of the UK and most of those in Australia are genetically different - the former being a wild strain from China and the latter a fast breeding/growing strain developed for aquaculture. A theory advanced, supported by one genetic study, is that the fast breeding strain introduced c1960 crossed with the strain/s introduced in 1870/1907 which had adapted to Australian conditions - producing a supercarp. That may or may not be the case.

Bob, your thinking on using competitors to limit carp numbers, at least after the virus is introduced, certainly has merit. But there are plenty of options with native fish rather than resorting to roach which could produce other problems.

Whether those native options are used is another matter. Unfortunately, for a range of reasons, I don't think it will happen. I think Murray cod and golden perch stockings will increase but that will largely be it.

Best Wishes

Truedogz

Bob Nudd wrote:

Mutley and Scruffy wrote:Are you sure it wouldn't lead to the same population of carp, yet a smaller average size? Just a thought with my limited knowledge! After all, I'm not a marine biologist!
cheers
Jim

i've been fishing a certain reservoir that has a well established population of roach for years. interestingly enough, i've never caught a single juvenile carp there, the smallest one was around 3 pounds.

Like I said, I am not a marine biologist, unlike broomstick who I would tend to listen to!

Sounds like we should be asking this Butcher guy to pay for the clean up...

4liters wrote:Sounds like we should be asking this Butcher guy to pay for the clean up...

What? Why? If you read Truedogz' post again, Alf Butcher tried to stop the introduction of carp

ugh you're right. My reading comprehension isn't great at 6am

The best solution I have heard is the virus that makes all carp male so they cannot reproduce, this would take longer but would solve the problem

Fishpod

What you are talking about is daughterless carp technology:

http://frdc.com.au/knowledge/publicatio ... nance.aspx

One of its drawbacks is that it would take a long time to bring carp numbers down - perhaps up to fifty years - compared with the virus. I hope that the research into this still continues as a supportive/backup measure to the virus as well as a means of controlling other pests like mosquito fish.

Truedogz

And on the other side of the planet...an article by UK fisheries concerned that the virus may be passed on with the use of anglers equipment!
https://marinescience.blog.gov.uk/2016/ ... equipment/
I had a quick look through it but need to read it more later. One thing I found interesting, when their sample number of carp were exposed to the virus within a controlled environment...not all of the fish succumbed! As mentioned, I haven't read it properly but I do assume it is discussing the same virus that will be released here. Interesting perspective from the other side...people who are trying to prevent the spread of this disease!
cheers
Jim,

Interesting to see so many thoughts on the virus, most of which are valid but the one overlying problem they haven't sorted out after 7 years of research is the danger of tons of rotting fish that will ultimately deoxigenate the water and the biggest losers of that will be the native fish which are far less tolerant than the carp .
Last January they had a small fish kill next to hindmarsh island and for a few weeks after the stench was unbearable, that was just a tiny speck of what is to come if the release the virus! God frigging help anyone living next to the river