58 replies to this topic

[Den]

There was a lot of hot long wind blowing about feral introduced fish a few weeks ago, however I see not much action seems to be taking place? I was wondering if we could colaborate a list of water ways that are known to harbour exotic fish- particularly cichlids. I would be interested to investigate these areas and perhaps colaborate some habitat data, and do a little fishing for these critters, would anyone else be interested?, I was hoping to get a small group of people with nets, thermometers and water testing kits together, it takes at least two people to drag a net, i'll take the shallow end thanks!

I think ideally this would be done as a group PCS initiative in co-operation with the relevant Gov Department where we could collect and pass on information to them that me be of help in eradicating or controling introduced feral species, however I am willing to do it alone if should there be no co-operation.

Cheers
Den

[topline]

I am a photographer for the Community Newspapers and was sent to take pics of the guys "catching" these critters. Hopefully the attached pic works and you can see a marker called "small Stream" its about 100m down Lord st off Benara.[IMG]http://i68.photobucket.com/albums/i28/topline_2006/FeralFish.jpg[/img]. It looks like a man made drainage ditch and is on the opposite sid of the road to some sort of church (7th day adventists.. I think).

If Image does not work, send me a PM with your email address and I'll send it through to you.

Cheers
Brian

[anchar]

Count me in Den....a Saturday would be best for me. I know someone that went and caught some brazillies the other week on a fishing line and I have been itching to give it a try. I think it would be a great public relations exercise too and may go a little way to show the relevant authories that the majority of fish hobbyists are responsible (and do care about the effect of aquarium fish on the enviroment).

Andrea

[Dr Cucumber]

Count me in also......However, Den is right, we must liase with Fisheries on this!! We would need to give them a call sometime next week to sort out which sites they have a) sampled so far and which prospective sites require investigation. Happy to make the call - as I have a few contacts there. I should also be able to borrow some handy equipment!!

I've already thought of several important data sets that could come from this:

a) Length frequency (gives an idea of size class cohorts and the timing of recruitment).

Gonad analysis - to give an idea of reproductive status

c) stomach content analysis - to give an idea of what they are eating.

We could even write it up as a small paper for 'Royal Society of Western Australia', or even 'Landscope magazine' (A CALM publication in similar vein to Australian Geographic).

Let me know how you want to progress.

[Den]

Thanks everyone so far, topline thanks for providing that info you've given us a fantastic start!.

Dr Cucumber thank's for offering to contact fisheries, I think we need to put our own action sheet together first, it would then be great if you could liase with them and ask what further information would be useful to them and any equipment you can get us would also be great!

Data collection / survey sheet :

Dr Cucumber I think the things you mentioned should be included in the survey sheet. Some of the things I suggest we add to the survey sheet, is a map of the water habitat : for expample if the fish were in a canal, you could measure water paramters within the inhabited areas and then measure water further down where the exotic is not present and see if there is any differences in Temp, Ph,salinity ect. If there were no differences one could assume the feral could spread further with time, this kind of method could allow you to calculate roughly how far a species could potentially spread within a waterway/habitat. We could then mark areas of the map with water parameters taken and areas we found the feral fish.

If we passed this info to Gov they could make an evaluation to possiblility eliminate feral before they spreads further. There are a number of differnent things we can do I guess to help.

I think once we get a few different locations listed it would be nice to get a group together and visit them, I think as Merjo has mentioned a Saturday would also suit me best.

Cheers
Den

[Dr Cucumber]

Yes, all good suggestions Den. I have sent you a PM with my contact details should you require any help.

Might be good to discuss details of some of things you propose.

cheers.

[anchar]

How scientific did you want to make it? I still have all my notes from my enviro. science degree somewhere with respect to water quality/parameters testing, vegetation and species abundancies etc. We would need to borrow devices for measuring salinity, turdity ( ), pH etc.

Andrea

[topline]

Hi All

This is a pic of the fish they were catching on the day.




Cheers
Brian

[Dr Cucumber]

Hi all,

Merjo, it will be difficult to do anything too complex. There are a number of potential paths we could take i.e. stomach contents, length/frequency, water quality analysis, sex ratios, GIS analysis of distribution, population studies (including a genetic analysis). However, most of these things require time, money and some level of expertise. A fantastic study would include a genetic analysis of stock. This would enable us to draw conclusions about the degree of linkage between populations / specimens i.e. have all the specimens come from a single pair of parents, or are we dealing with multiple releases (in different areas) of a number of pairs of broodstock. To do this properly we really need the support / collaboration of fisheries (including financial support). However, a study like this is beyond the scope of a community / club based project given its expence. It is really an ideal honours project for someone - that way there would be full access to labs / equipment / funds etc...... Any graduates out there??

The spatial analysis of water quality v cichlid distribution proposed by Den is a good idea, but I have some reservations about the value of such an exercise. Sorry Den, but my main concern is that the water quality is unlikley to vary over a small spatial scale. Unless, the main feral populations are located near drain pipes that maintain higher temps or certain pH readings, the chances of small scale changes in habitat affecting distribution are small. The easiest type of study would be a length / frequency analysis. This is non destructive and gives us cool information on the number of size classes present i.e. an indication of whether the population is producing multiple cohorts of juveniles..............I would be surprised if fisheries havent been doing this already. That is why I think we need to contact fisheries before we move on anything........there may also be a small issue of permits we need to sort out (although, given the feral nature of the beasts, it may be open slather!). Anyway, not to put a dampner on everything. I am still more than keen to be involved in some sort of project. My suggestion is length frequency, sex ratios and if possible, a stomach contents analysis.

Best regards,

Dr Cuc

[anchar]

Count me out if we have to dissect them..sorry but I couldn't do it.

Andrea

[Den]

Hi All

Lol Merjo,

My interest is mainly to do a basic study the water habitat and to catch some of these ferals, should other team members wish to take some captured fish to a lab for closer analysis that would be up to them but I don't think anyone would be bringing scalpels to the waterside.

To what level the study is taken would depend on the team consensus and what extra study individuals wished to take up on their own is their own choice.

I guess the study could be split in two halves : Fish & habitat

Dr Cucumber your suggestion of length frequency, sex ratios and "maybe" a stomach contents analysis are good ideas for a start.

Regarding Habitat study a basic start I guess would be PH, Salinity, Temp, water depth.

We can add to this off course whatever other members and fisheries felt is appropriate. This is a basic start, participant and fisheries feedback will determine what the end study parameters will be.

Anyway Merjo hope you are still interest and I hope more people can get involved, we still need a couple more feral affected areas, anyone know anymore feral spots?

PS. Dr Cuc your PM didn't come through, would it be possible to get from fisheries a list of where ferals are known to be, I think before we contact fisheries about a mini research expedition we would need to gauge a better idea of who and how many people we will have involved and an idea of our accumulated capabilities.

Anyway just my thoughts look forward to everyones feedback,

Cheers
Den

[Cicolid]

G'day Den..

You can count both of us in depending on where & when...as we live 25 klm south of Mandurah..

Must emphasise that we are both novices at this, but we are both willing to help where we can..

Cheers
Col & Lyn

[anchar]

Ok...I'm back in again if there is to be no blood spilling. So is giz.

Andrea

[Den]

Hi All

Glad to hear you are back in Merjo.

Thanks Col, I am also an amature at this so I hoping we can have a mix of people guided by the lead of a proffessional or two in this field (someone like Dr Cucumber. I am hoping he or someone at his level will offer to lead this project) so it won't matter if you are an amature or not,

I am hoping this can be a interesting and educational experience for everyone involved no matter what level you are at.

Cheer
Den

[thomascl]

count me in too.

[mtchye]

Just a quick note to say that the method of capturing these fish will probably need to fall within fisheries guidelines, i.e. no netting, hook and line only.. etc

Also need to give some consideration to what you are going to do with the fish, once caught...

All in all it should be an interesting exercise and I wish I had the time to check it out!

Good luck guys and get some pics for us!

[anchar]

On the news tonight, they said they are going to start poisoning them shortly.

Andrea

[keenas]

Whats that going to do to the natural aquatic environment. Surely they dont have something that is genus specific :?:

[Noddy65]

I saw the same report. Theyre about to start poisoning, electrocuting and using explosives on them.
They will also knock off any natives, turtles, frogs etc but the reasoning is (and I think its valid), that these cichlids are knocking off the natives anyway and they really have to hit them hard ASAP. Theyre moving as many turtles as they can and are doing it now to reduce the effects on frogs.

I think it starts this Friday.

Mike

[keenas]

Couldnt they do some kind of dredge, or maybe introduce a sedative to the water, then remove the invaders. I would have thought that this would be a better way of control and have less impact on the local habitats.