Hatchling Perch

We were asked to take some fertilised eggs and hatchlings home with us if we liked so we could observe them developing I set up a small tank that was sitting at home doing nothing and they seem to be surviving alright in it !!
They are very small and hard to see and after half a dozen attempts at photographing them I got a pic where you can actually see several of them , I can not say how many I have in there as they are very hard to count I would estimate around about 20 but I could be wrong I was told they would survive about a week but I will try and grow them out .
If you look at the water line just of centre to the right
you can see one and if you look closely you will see others around it but like I said earlier they are hard to see .

Thousands of fingerlings

Here is what thousands of baby perch look like they are very hard to catch while in the ponds , some one suggested dynomite wich would be a heaps easier than trying to net them .











I actually brought some home with me about 18 or so they all survived the trip home I thought I would have lost a few but they all made it !
The babe yabby's have some play mates to keep them company they better start growing or they will end up being fish food , I would say at this point in time they are large enough not to be bothered by them but not by much mabe one molt or so.

Netting perch fingerlings at Gingin

Here is the end result of some old fashion blood sweat and tears dragging a net through mud scum rocks and weeds !!!
I am just glad I was the camera man :)
As you can see its not a bad catch thats if you like tadpoles there seems to be a plague of them
there are few perch fingerlings amongst that lot but pound for pound tadpoles rain supreme.The tadpoles were transfered to a pond containing larger perch apparently the larger perch dont mind snacking on them from time to time .
The perch fingerlings were taken back to the shed where there is a suitable holding tank for them from there they can be observed then sent out to customers.

Fatality

Yet another moult and alas another kill , the yabby's have plenty of food and there water is well aerated the water temp is probably a little high but I think that makes the more sluggish than any thing .
I have recently introduced the other female back into the adult yabby's tank and suspect that the males kill each other to eliminate the competition for mateing , they didn't eat this one its tale had been bitten and they were in the process of eating its shedded shell.
I have read on the net that some guy has found a way of eliminating caniblism but he is keeping a tight lip on how he is doing it I think the new cross breed that produces male only juveniles is being used thus eliminating the competition factor and allowing higher stocking densities with out the losses ,thats my theory any way.

Mother moults no loses

I checked in this morning on the juvenile stock to see if there was any movement , it was no surprise not to see any !
The juveniles only seem to come out at night I guess the fish I have in there keep them on there toes
I am not sure if this is normal behaviour but I think its a safe bet to say that it is a defense mechanism.
I have cracked gravel in the tank wich seems to be great for juveniles as there is heaps of spaces between the gravel for them to disapear into , not such a good idea though if I had to transfer them to another tank as it would be almost impossible to catch them unless I made some kind of mini trap for them.
Any way while I was checking I noticed that the mother had moulted I checked to see if there were any juveniles left on it but the empty shell was clean I am assuming that they all made it ?
then again the fish may have had a good breakfast !!!
The PH in both my systems is 7.5 it doesn't seem to move from there it may be the reason they are moulting so much and around spawning as there is an excess of calcium in the water , the plants in the grow beds are growing good as well wich is surprising me , one of the strawberry plants has flowered and the hot and spicy oregano has tripled in size .

Juvenile yabbies

I haven't been able to see the egg bareing female for ages in the day time so I thought I would try at night with a torch , to my surprise she was out of her hiding place and there must have been 20 or so juveniles scattered around the tank , they are swimming around like prawns crawling up the sides of the tank they are every where , I caught the female to see if she had any thing left on her and there is still heaps of eggs hanging off her so they must drop them off in groups over a week or so ? .
I have about 8 fish in the tank with them 4 guppies and 4 redfin blue eyes I am not sure if they will eat them if I do notice them taking them I will remove them from the tank , they didn't when I was watching but they may have already had there fill !!!
Here is a few pics of them , there is a guppy next to one of them to give you an indication of there size I have read that high mortality rates in juveniles is to be expected but only time will tell.

Another moult no fatalities

While checking on the yabby's today I noticed that one had moulted , at first I thought I would find another munted yabby but to my surprise I couldn't see any carnage .
I did notice one of them had a claw from the moulted shell on the other side of the tank so he must have had a close call ! there is plenty of pipes laying around so he must have ducked into one of those .
I am not sure if canablism is because they are hungry or is a natural way for them to keep there population in check ? I have been over feeding them a bit mabe that is why they didn't kill him or mabe he was just lucky .

Biofilter starting to work

I tested ammonia and nitrites again in my new system they are both at 1 wich is a good sign the water turbitity cleared up and it looks crystal clear , I added various plants into the grow beds a couple of strawberries and some cuttings , oregano some kind of a curry plant rosemary some wormwood and no idea what the last one is , some of them look a little sickly but are still alive and to be fair they are not really cuttings they were wrenched off as I walked past so I think its a good sign that they are still alive .The female yabbie settled in fine and is very healthy took me ages to catch it as it flicked around the tank I added in five red fin blue eye or feeder fish if you like and they are doing fine also.I bought some marron food for them but they dont seem that interested in it , well not when I am looking any way they do like meal worms the odd snail when I catch them in the grow beds and an apple core now and then !!
Here is some more pics so you can see the difference.

spawning yabby's

I came across some info on the net at www.fish.wa.gov.au/docs/aq/aq001/aq001page02.php?0309 it says that females dont molt while they are spawning !!! well the ones I have seem to , one of them has molted then came back later and fed on the babies attached to the sheded shell .
I dont care so much because the other female has alot more eggs on her than that one did ! hopefully she is a better mother , I think I will wait several days for its shell to harden before I place it in the other tank with the males , "after the last episode" , not that she deserves it !!
Here is a pic of the new system I made its got a stronger pump so I was able to make a flood and drain system and add another grow bed into it , the amonoia levels jumped up to 6 after the canablism incident so I dumped some water I didn't bother with nitrites because I know the biofilter wont kick in for a while.
The first system I built is working fine amonia and nitrites non existant and the watercres is growing well hopefully the remaining egg barring female will give me some much needed stock.

aquaponics

I seperated the male yabby's from the females so they wouldn't harrass and eat the berries off them I noticed one of the males was a little softer than the others when I was transfering it to the new tank
I thought it must have already moulted and had eaten its shell because I couldn't see it any where , I checked on them today to see how they were settling in and I noticed on the bottom of the tank that it had molted and its shell was laying next to a piece of pipe , the turbidity isn't to good as its a new system and azolla is floating on the surface wich makes it hard to see !! on closer inspection I noticed a mutilated corpse of a yabby they had canibalised it !!!
Now that I think about it when we were at mount barker females with berries and soft shelled marron were seperated from the other marron and placed into pond 3 now I know why .
(One down seven to go) :)

Michael's first practical workshop

Saturday

Tour of the farm and harvesting marron

Tony took us for a farm tour , which also acted as an farm inspection and maintenance appraisal , as a new pipe coupling was required to be fitted at one of the ponds . We then loaded net , tubs , rinsing tank , all the equipment needed for harvesting Marron on the trailer and moved up to ponds at top of property . We removed the hides , netted the pond , scooped up marron into tubs , these were either rinsed of mud in tub or washed with hose connected to pond pump , this is to remove bacteria in the mud from the marron as this can kill them , it is also important to not expose marron too long and transport marron to purging tanks quickly.

Marron Purging Tanks

These tanks are oxygenated and have continual water flow. Marron were removed from tanks a small number at a time , and weighed and sorted . Egg bearing females were returned to pond Three along with any soft shell marron . Small marron under 40g were returned to pond Six .

Click To Play

This is a video of what we did at out practical workshop on a

Marron/trout farm (Western Australia) in October, 2006.

Sunday

We harvested and processed 70 Trout
Equipment needed for harvesting was set up at an outside purging tank , only suitable and set up outside for winter . We all scooped trout from tank, and killed the trout with a double pronged spike , one for brain one at start of spine . These are kept in an ice slurry until ready for processing .

The trout are then moved to the processing room , which meets all health dept. regulations . Washable floors, walls, stainless steel work benches, hot water, sink etc. Proper PPE is needed for processing Trout, such as steel mesh glove , apron , rubber boots . There the trout were gilled and gutted and cleaned. They are then packed on ice ready for packaging and delivery .

Unfortunately I did not have the camera on Sunday for the trout processing, and of course I cannot go into too much detail or specifics about certain aspects of production until further study and progress into the course is achieved . It was a very interesting and enlightening experience , I had a fantastic time and look forward to the next field trip , and of course I now have more questions than when I started.

This feedback was supplied by Michael who has justed the course.

aquaponics

Hi every one here is some pics of an evolving system in progress these first pics are of my first attempt at aquaponics and yabby farming as you can see they are doing fine ! several of them have berries on them so I need to expand my operation and setup another tank I thought it would be a good idea to do this so I could get some hands on experience !!! its on a small scale and looks a bit rough but now I can play around with water quality feeding rates ect .

I purchased some testing kits from Connie they are a very reasonable priced and are easy to use thanks again Connie ,, I tested my tank for the first time today and here is the results.

• PH 7.5
• Ammonia 2.0
• Nitrite 2.0
• Phosphate 2.0

I dropped some water out of the tank and replaced it to get the nitrite and amonia levels down a bit I will also stop feeding them for a few days I think the ph and phosphate is ok hopefully the biofilter will kick in soon .

Aquaculture Team Blog

This is a blog has been set up for my aquaculture e-learning students, from Challenger TAFE in Perth (Western Australia) to share their experiences. The aquaculture e-learning students are based off-campus and study aquaculture online using WebCT and Elluminate.

We have regular 2 day workshops, normally on Saturday/Sundays, which gives them the opportunity to practise the practical skills and have their practical skills assessed.

The last practical workshop was conducted in October, 2006 and was based on a trout and marron farm in Mt Barker (approx. 4 hours from Perth). The students had a lovely time learning how to handle, harvest and process marron and trout. This is a picture of Andrew Matthews, another aquaculture lecturer, on our recent field trip.