Backyard Aquaponics
A place to discuss aquaponics

At the moment Tilapia are confined to a small number of water systems... introducing more, or into more systems...

Just hastens their spread... and kills off native species...


Well there is for Carp... and the recent drought reduced their numbers substantially...


Nope, not any longer.... all states have now moved to ban them...

Interesting topic...I'm bored at work so here is my 2 cents.

I would support native species.

The more demand, the more supply, excess supplies just mean cheaper supply overall.

Truely excess supplies will aid in stocking programs.

If there were a viable cold water ntive species other than trout, I would probabaly go with them also.

Having said that, trout seems to be accepted as qausi native in the colder regions.

Florida is probably not the best example of a government allowing exotics. Florida may have the biggest invasive species problem of anywhere in the world. Tilapia would be way down on the list or worries, assuming they aren't being eaten by native and non-natives as fast as they're reproducing. While farming interests in the US are strong, tilapia can only survive and reproduce in a very limited area of the US. In general, if it will die in the wild they'll let you raise it. Crayfish native to the US, but not native to Wisconsin are banned here. Try growing them for bait (far more profitable than growing fish for food) and the DNR will send you enough fines and cease and desist orders to wallpaper a mansion.

Cows, pigs, sheep and chickens have been domesticated for thousands of years. Selective breeding have made them dominate on farms. Zoos spend a fortune trying to keep their inmates alive. Place most wild animals in a farm and they'll drop dead. They certainly won't be profitable to raise. Trout have been selectively bred to where the farm raised varieties are pretty distinct from their wild cousins. What we need are selective breeding programs for other species. It takes decades, but it's the solution.

Well there is for Carp... and the recent drought reduced their numbers substantially...
>>
So now the ones that survive are going to be drought tolerant as well.

Ah well shame about the tilapia, theres always one idiot who ruins it for the rest of us.

If i had excess young i'd just feed them back to the adults or to the chickens.

Don't get me wrong i like natives and i like the fact that silvers have high omega 3 etc but it seems wrong to have to inject a fish with hormones to induce breeding. whats going to happen when you can't access hormones. where do they get these hormones anyway? what are they?

Yeah I can't see why they banned Koi for that reason - they aren't very hardy compared to common carp. I'd like to see a silver perch variety specific for farming and maybe possibly breedable.

The common hormone used to induce native fish to breed is Human Chorionic Gonadotropin. It actually comes from the placenta of women so as long as humans continue to have babies I dont think we will ever run out of it. Its also commonly used to get other animals to breed such as horses and illegally used by sportsmen and body builders as it increases their testosterone levels. Getting the fish to actually spawn is only half the problem, the raising of the larvae into fry is generally the more difficult part due to the very small size of the larvae when the eggs hatch and the fact that they will only eat live foods.

Raising fry isnt that hard... you just need a good starter culture of rotifers and/or baby brine shrimp depending on the fish. And water changes, lots of water changes.There was ways i've induced breeding in my fish in the past that I wouldn't mind trying. When i was breeding tetras which come from you'd simulate "the wet season" aka breeding by draining the tank 3/4 and topping up with rainwater. Hard to say if its possible with i.e. silvers need to do more research. Maybe if you added heaps of flow to the tank after doing it, it would stimulate "rapid river flooding".

Hah, tried hatching brine shrimp 3 times with different batches of eggs and no go. Why dont we have a native fish thats easy to breed.
Have bred guppies and kribensis in the aquariums here without lifting a finger

The early tests of breeding Silvers were done by raising the water level 1 metre in ponds. The fish spawned but the eggs died as they need to be kept in suspension as they would in nature moving down a flooded river.

Really no go with brine? Ive raised some to adulthood with yeast. Then the ammonia hit about 10 and they died...so you need water changes there if you use yeast lol but if you get a tank outside, put an airstone, get some "miracle grow" chuck it in, the water goes green, chuck some brine in and presto, self sustaining population of brine shrimp indefinitely.

Back to the silvers... If in ponds I agree, no go. As you've said those eggs are negatively bouyant, which is kind of annoying... you'd need a tank to spawn them in, with a net underneath. After spawning you could capture all the eggs and chuck them in an egg tumbler - like you do baby brine shrimp eggs - they are also negatively buoyant. Basically a coke bottle upside down with an air stone in the bottom. The biggest thing will be: do they need space to move to induce breeding or would it be ok to do in an IBC. I mean ive seen the breeding set ups at one of the aquaculture facilities and they're like 2000L breeding tanks, but thats after hormone injection. I think I may have to give it a go... How long do they take to become sexually mature?

You speak as if it is so easy to do.

I think breeding aquarium fish is much more different that natives.

Some aquarium fish have fry if you look at them funny.

My crowning glory was breeding green and red horseface chiclids.

If and when you have your silver fingerlings available I'll take about 100 a year.

yeah thats why i wanted tilapia or carp, easy breeders. A guy I know breeds marine tropical reef fish and shrimp. Its hardcore, but he somehow pulls it off. Hes had successful hatching with fish that seem so far out of the possibility of breeding. Thats why im more hopefull about silvers. i think as a general rule of thumb fresh water fish are easier. Silvers aren't like barra, they stay in fresh water all their life. Barra are males in fresh water, females in salt, breed in brackish, then half split up etc etc that'd be nightmare to stimulate natural breeding conditions.

Im thinking like this; certain genes get turned on to wake up the old fish hormones when certain conditions are met. It seems like the easy part will be the big water change to stimulate a sudden down pour, the hard part will be getting to those eggs quickly and separating them out. I probably wouldn't have a high success ratio with the fry, as in i'd probably only get 100 per breed session because they normally chuck all the thousands of fry into ponds with plenty of micro life etc. The other thing would be will they still want to breed in a smaller space.

Sorry Moekuc... but I think you need to do copious amounts of further research...

If you serious about attempting to spawn Silvers... I'd recommend you do the hatchery course at Natfish in Grafton...

And that you contact Stu ("Monya")... who did that course.... and ask him about his experiences to date in attempting to spawn Silvers.. and keep the fry alive...

Even the most seasoned "commercial" hatcheries.... sometimes have massive failure rates...

And they've invested hundreds of thousands of dollars of money, and years of training... and hours and hours of time...

Nobody to my knowledge has successfully spawned (without hormone injection)... and/or raised Silver Perch fry to fingerling... in a RAS environment...

And that includes the guru of Silver Perch research... Stuart Rowland...

Breeding fish in an aquarium has only a very finite number of variables. Water quality, ph, temp and a place to spawn.

Completely different to aquaculture. Unless you have the equipment to control all the above.

If you consider natives unsustainable if they need to be shipped you should consider building your own pumps, etc as well. It is darned difficult to disentangle ourselves from the economic web that makes our lives so easy, filled with inexpensive goods, and dependent on unsustainable manipulations. The best we can do is each reduce our crushing weight on the world by being a bit more mindful of the ripples we send out with every action. This question of the effects of our actions is something we often overlook with good ideas like biofuels, AP, etc.

And then there are the economists and politicians who say we need to continue "growing our economies".

However, I would bet that, as far as fish go, when AP becomes more popular there will be more local producers of fingerlings and you won't need to ship them so far. No worries.

what else do you have to consider in breeding a silver perch compared to a ie a cichlid?

no dbout pumps etc are difficult to build but you can buy very good quality pumps that will last a very long time. AP isnt as sustainable as permaculture but i think you can put the technology to very good use long term.

it would be good to domesticate silvers etc for long term success.