Nile Tilapia

We have a problem with invasive Nile tilapia (Oreochromis niloticus) in southern Mississippi (ecapees from aquaculture facilities that have established breeding populations in the wild). I just pulled these out of a swamp behind our offices yesterday. Until a recent high water event, our tiny corner of Jackson County hadn't been invaded. Wonder what will happen to the local native fishes, particularly centrarchids..............?


Take care,
Gretchen

We have a problem with invasive Nile tilapia (Oreochromis niloticus) in southern Mississippi (ecapees from aquaculture facilities that have established breeding populations in the wild). I just pulled these out of a swamp behind our offices yesterday.

Is it legal to collect/ship these? I'm looking for a fish to breed as feeders, and someone recommended these guys.
http://forum.nanfa.o...h...ost&p=34747
I'm talking about an indoor tank so no chance of escape (and I live in Vermont -- they couldn't survive here anyway). But... it it's against the law, I guess I'll need to get them from a legal source (aquaculture, I guess).

Thanks, Jase

Is it legal to collect/ship these? I'm looking for a fish to breed as feeders, and someone recommended these guys.
http://forum.nanfa.o...h...ost&p=34747
I'm talking about an indoor tank so no chance of escape (and I live in Vermont -- they couldn't survive here anyway). But... it it's against the law, I guess I'll need to get them from a legal source (aquaculture, I guess).

Thanks, Jase

For aquaculture purposes, I believe (hope!) you need to get them from a legal source. If you choose to aquaculture these fish please be very ecologically resposible with your operation. People thought they couldn't survive in MS either (I know VT is much colder, however...).

Take care,
Gretchen

For aquaculture purposes, I believe (hope!) you need to get them from a legal source. If you choose to aquaculture these fish please be very ecologically resposible with your operation. People thought they couldn't survive in MS either (I know VT is much colder, however...).

Take care, Gretchen

Ok, so you're telling me that you can't catch and ship some? I'm not setting up aquaculture -- just looking to raise some largish fry in an aquarium to feed to redfin pickerel.

I grew up on the shores of the Great Lakes and my background is conservation biology. Trust me, I know the story on aquatic invasives. I actually did my undergrad thesis as a review paper of invasives in the Great Lakes. I'm not sure I'd risk having tilapia in an outdoor tank here, even though I'm pretty sure even the toughest tilapia out there wouldn't make it through a single VT winter...

Cheers, Jase

For aquaculture purposes, I believe (hope!) you need to get them from a legal source. If you choose to aquaculture these fish please be very ecologically resposible with your operation. People thought they couldn't survive in MS either (I know VT is much colder, however...).

Take care,
Gretchen

In many of the more concerned states, production of tilapia can only be done in certified indoor facilities. Not everyone thought Nile tilapia could not tolerate a mild temperate climate of southern Mississippi as at least a couple producers raise tilapia under similar conditions in Arkansas.

I think production of tilapia should only be done under extremely controlled conditions indoors unless at latitudes well outside the tolerance range of the exotic species in question. Accurate knowledge of tolerance range would be needed.

The competition issue with centrarchids it seems would be more to do with nesting habitat which to me seems not to be all that limiting. Competition with trophically similar but morphologically dissimilar groups would be to me the more immediate concern.

What is going on know with native centrarchids and introduced tilapia in southern Florida? Some studies have been conducted. May provide insight into what a population in Mississippi might do.

Ok, so you're telling me that you can't catch and ship some?

Come on down and clean up our system! Maybe then we can eradicate them.

We've done a fair bit of research on tilapia in this area and I can provide a list of publications if anyone is interested. We've looked at feeding habits, reproductive behavior and biology, ties to thermal effluents, and age and growth. There are many papers concerning other invasive tilapiine species availible for the Gulf states, also.

Edited by silverperch, 10 April 2008 - 04:56 PM.

I think production of tilapia should only be done under extremely controlled conditions indoors unless at latitudes well outside the tolerance range of the exotic species in question. Accurate knowledge of tolerance range would be needed.

How's this look for "well outside the tolerance range"?
http://tinyurl.com/3sbz4x
http://www.weather.c...y/monthly/05477
http://www.victoryse...m/frost/vt.html

Especially check my *average* January lows. February looks about the same.
http://www.weather.c...77?climoMonth=1

Of course I'd do a lot more research (even beyond what the state might require) I were ever going to think of doing actual aquaculture of tilapia here -- but for keeping a couple in an aquarium indoors, I'd feel pretty comfortable here.

I'm going to look into an aquaculture license anyway -- I've been wanting to do it for a while anyway, and I'm buying property that might let me start. I'd be looking at yellow perch, not tilapia, though. Vermont just isn't cut out for tilapia unless it's indoors or in a well-heated greenhouse.

-Jase

Edited by jase, 10 April 2008 - 04:57 PM.

How's this look for "well outside the tolerance range"?
http://tinyurl.com/3sbz4x
http://www.weather.c...y/monthly/05477
http://www.victoryse...m/frost/vt.html

Especially check my *average* January lows. February looks about the same.
http://www.weather.c...77?climoMonth=1

Of course I'd do a lot more research (even beyond what the state might require) I were ever going to think of doing actual aquaculture of tilapia here -- but for keeping a couple in an aquarium indoors, I'd feel pretty comfortable here.

I'm going to look into an aquaculture license anyway -- I've been wanting to do it for a while anyway, and I'm buying property that might let me start. I'd be looking at yellow perch, not tilapia, though. Vermont just isn't cut out for tilapia unless it's indoors or in a well-heated greenhouse.

-Jase

I agree, you are beyond what a Nile tilapia can tolerate. Heating bills will be your undoing if you decided to rear the species for the going market price. Heating issues would even be an issue with yellow perch.

I agree, you are beyond what a Nile tilapia can tolerate. Heating bills will be your undoing if you decided to rear the species for the going market price. Heating issues would even be an issue with yellow perch.

Yeah, unless I decided to be one of those nutjobs who raises them for personal consumption in a plastic swimming pool in his basement -- and I *am* that nutty. I actually had bought a 12' pool for that purpose 2 years ago -- when I lived in an *apartment* with a basement. I eventually came to my senses...

Heres a paper considering the effects of introduction into N. American watersheds:

http://www.specifyso...al_CJF_2006.pdf

Though as to what specific effects they may have on out-competing natives, I would say it's a pretty scary proposition considering what the damage they've already done in Lake Victoria, with hundreds of species forced into extinction as a result.

It's also quite amazing that any state government would allow the aquaculture of such a species (except under the most controlled conditions) given their demonstrated potential for ecological devastation in the third world.

Edited by BLChristie, 10 April 2008 - 10:13 PM.

What is going on know with native centrarchids and introduced tilapia in southern Florida? Some studies have been conducted. May provide insight into what a population in Mississippi might do.

We will know soon enough

Heres a paper considering the effects of introduction into N. American watersheds:

http://www.specifyso...al_CJF_2006.pdf

Though as to what specific effects they may have on out-competing natives, I would say it's a pretty scary proposition considering what the damage they've already done in Lake Victoria, with hundreds of species forced into extinction as a result.

It's also quite amazing that any state government would allow the aquaculture of such a species (except under the most controlled conditions) given their demonstrated potential for ecological devastation in the third world.

Every single species we move around for use in hobby, research, food, bait and public aquarium display has the capacity to become an invasive, even the rare endangered.

The Lake Victoria disaster is based on Nile perch is it not, rather than Nile tilapia? I think Nile tilapia is having its way in some other lakes.

tilapia sure are tasty! I was also recommended to raise them for feeders, however, i'm pretty sure that I would end up being the one eating them

http://www.mdwfp.com...es_tilapia.html

I fish a local lake that has well established populations of O. Aurea.

Bass love them as forage and they do a fair job of eating plants.

Don't think they are going to eradicate your bluegills

It is interesting that O. Niloticus is surviving in Mississippi

Edited by Gambusia, 11 April 2008 - 03:58 PM.

I fish a local lake that has well established populations of O. Aurea.

Bass love them as forage and they do a fair job of eating plants.

Don't think they are going to eradicate your bluegills

It is interesting that O. Niloticus is surviving in Mississippi

We think they will cause problems for our native fishes by changing the ecosystem because they are bottom-up feeders( i.e. they eat detritus, algae, and other plant material). As you said they do a fair job of eating plants. The environment I just collected them in is heavily vegetated and is prime habitat for all sorts of neat centrachids, bowfin, fundulids, gar, brown bullhead, and other fish that like that kind of habitat. The question is what would happen to that habitat with a healthy population of tilapia that feed at the base of the food chain? Would the vegetation decrease? Would sediment characteristics change (Less veg. may allow water to flow faster so sediments would become coarser) ? How would these things affect the native fish communities?

We think they will cause problems for our native fishes by changing the ecosystem because they are bottom-up feeders( i.e. they eat detritus, algae, and other plant material). As you said they do a fair job of eating plants. The environment I just collected them in is heavily vegetated and is prime habitat for all sorts of neat centrachids, bowfin, fundulids, gar, brown bullhead, and other fish that like that kind of habitat. The question is what would happen to that habitat with a healthy population of tilapia that feed at the base of the food chain? Would the vegetation decrease? Would sediment characteristics change (Less veg. may allow water to flow faster so sediments would become coarser) ? How would these things affect the native fish communities?

In within the U.S., habitats now supporting tilapia, what has been the response of predators? Do they target tilapia as they become more abundant? Also care miust be taken from extrapolating patterns associated with different tiliapia species. Nile tilapia are definantly deposit feeders and more capable of filter feeding than many of their relatives but I do not think they will target vegetation directly as some of the other species may be prone. Rather damage to vegetation will be incidental with heavy foraging for limiting deposits as tilapia abundance increases. Hence the concern about what potential predatorss will do. Have worked with tilapia in pond settings and their affects seem to be a function of their density. What species are sympatric and feed upon the same foods? Sediment characteristics do change in ponds.

On the whole for the short term, establishing nile tilapia will be a problem for some natives but the mechanisms may not restrict themselves or be most important similar species.

A friend of mine is doing his dissertation on the effects and spread of tilapia in Belize. I'm not familiar with all the details yet, but from what I understand they have altered aquatic systems from the bottom up.

I believe in the Salton Sea in California the Mozambique tilapia has become the most abundant fish.

They can become abundant

In many Mexican bass impoundments, tilapia are the primary forage for largemouth bass

No doubt they were stocked as forage and as a food fish

Edited by Gambusia, 14 April 2008 - 06:38 PM.