Quality fry/fingerlings are the result of good brood fish management. We produce fish, specificly for grow out farms. For over a quarter of a century I have been line breeding our fish. Selecting for desirable qualities such as body shape, disease resistance, spots, and of course, fast growers. Our breeders have been selected each season from fish obtained from our fingerling customers in Australia and our own "super shooters", and fresh wild fish. That is many generations of line bred fish!
No hatchery anywhere has this history of line breeding Australian perch !
The fish we select from our Australian fingerling customers have been chosen from the first harvest of grow-out ponds. This means, we chose, usually about 50 fish from the very biggest of the pond being harvested, for the first time. That is, 50 out of thousands of fish. We also keep some fish from our own fingerling ponds. These particular fish are exceptional growers. I call them "super shooters." When we stock one of our ponds with larvae to grow on to fry for our customers, there are often a couple of fish that stand out. The pond harvest is tens of thousands of fish, and 2 to 5 of these fish are outstanding. The average weight of the fish being harvested may be about .3 of a gram, but these super shooters weigh many grams each. Hundreds of times bigger than the other fish in the pond.
We also, under special permit, collect fresh wild fish to prevent our fish from becoming, inbred. We do this under advice from scientists and geneticists. They are the experts, and they advise us that if we don not introduce fresh wild genes we may find issues developing in our fingerlings and fry. Issues such as physical deformities, poor disease resistance, poor growth perfomance. Poor growth performance may manifest itself in a number of ways. Slow growth over the entire grow-out phase, or poor growth performance after the fish reach a certain size. for example, fish may reach 500 grams quickly, but do not reach 800 - 850 grams as quickly as they did in earlier generations of fish. Australian growers reported, very early in the history of the perch grow-out in Australia, that it was easy to grow fish from 500 grams to 800 grams. The reported that this is where the easy profit was to be made. That is not the case now, with some farms. Those farms find that the fish growth slower noticeable after 500 grams. This can be common in some species of fish. Take tilapia for example. This species can stunt readily. They have been commonly reported to become reproductive at a very small size, with very slow growth performance. This should be taken as a warning than inattention to genetic management can and does result in catastrophic losses of profit to grow-out farms.
One of the important ways we manage our genetics is the use of micro chips. Breeders are micro chipped so we can identify individual fish. We know exactly which fish were the parents of every batch of fry/fingerlings.
We have enhanced our management of brood fish to avoid inbreeding. Other countries have experienced inbreeding issues which have resulted in the loss of disease resistance, and slow growth rates over 500 grams. Spots have also been lost by some hatcheries. We have been line breeding for over 25 years. Wild fish are introduced into the blood line at intervals to maintain the desirable qualities jade perch inherit from their ancestors. Scientists have advised us that we need to introduce wild genes to avoid loosing the special qualities that are so desirable in jade perch, such as fast growing, and disease resistance. Spots are something we have recently been selecting for because of requests from Asian customers.
What is a microchip?
Microchips, or PIT tags, Passive Integrated Transponders, are used for identification of individual fish.
They are inserted under the skin or into the muscle of the fish, usually next to the dorsal fin. They are inserted using a, single use, special applicator. The micro chips do not interfere with an animal’s normal functions. This process is carried out while the fish is anesthetized. Anaesthesia is recommended for the safety of the fish as struggling during handling can result in injury to the fish and the person inserting the chip.
A microchip is a small electronic device about the thickness of a ball point pen refill, and about 12mm long.
Each microchip contains a silicon chip that is encoded with an individual number. The components are sealed in biocompatible glass which renders the chip inert when implanted into an animal. To read the number, a scanner is moved over the implanted microchip and a signal passes between the chip and the scanner. The scanner translates the signal and displays it on a screen as a number.
Prior to implantation, the implant site is swabbed with dilute antiseptic (e.g. Betadine or alcohol). We inserted the chips on the left side at the base of the dorsal fin. Glass chips should not be used if there is any chance the fish may be used for human consumption.
Tissue glue is used to seal the insertion site.
Australian code for the care and use of animals for scientific purposes (8th Edition 2013).