'hybrid' freshwater fish ?

[RiverRat]

My pastime is freshwater angling. The ODNR stocks on a yearly basis many tens of thousands of fingerling hybrid bass (Morone saxatilis x M. chrysops) and saugeye (Stizostedion vitreum x S. canadense).

It is my understanding that these hybrid fish are sterile; yet, I have come across some literature that states there are small portions that spawn. Is this benign ‘tinkering’ or is there the potential for an adverse impact on the host system over many, many years of stocking?

Does anyone know the rational for the start of such cross breeding?

[Fishteacher73]

While I am personally not familliar with these specific hybrids, yes most hybrids are sterile. I am sure that there may be abberations that are fertile, but the trick would be to find the other statistical oddity. (Not impossible, but reasonably unlikely). Usualy when hybrids are introduce into the "sport" realm of animals it is for two reasons:

A) Increased size of the target animal (Everyone wants a bigger fish)

B) Better ability to survive various abiotic factors (Temp., water chemistry,etc) (Allows them to get bigger too).

In many streams where I grew up (TN outside the Smokey Moutain Nat'l Park) many of the streams were stocked with rainbow trout. These fish slowly replaced the indiginous brown trout. Only a few streams still have brown trout in them (The water system is broken up by many waterfalls that reduces the ability to move populations up-stream).There are down-sides to external stocking. This has been done for about the last 15 years, and I have not seen anything that indicates that they are spreading.

Non indiginous animals can cause a lot of problems. Hawaii 's fauna has ben decimated by foriegn species. Much of Austrailia's wildlife is threatened because of invader species. There is even thought that there is a sustainable breeding population of Burmese pythons now in FL.

Many areas stock tilapia sp. (an African cichlid) in thermally poluted waters (Dams power plants, etc). They survive well and are not a bad food fish. They really cannot move outside of these areas because the water temp is too cold to facilitate breeding.

[bumab]

Another use of hybrid fish is pest control. Some folk have started using fish with 3 copies of their chromosomes to eat milfoil. A simple chemical (can't remember which) at fertilization stops the chromosomal seperation process creating polyploid fish, which are sterile.

Its' not really a hybrid, but its a cool use of fish.

(I think it's the striped bass, but i'm not sure. Thought they were predators...)

[Fishteacher73]

Not a hybrid either; but a cool engineered fish is the glofish. This is a common zebra danio (Brachydanio rerio ) that has been genetically alter to have flourescent green or pink color. They were oiginally produced to be used as indicator species in polution studies. They have also found their way into the ornamental fish industry as well.

Here is an article about the original use:

http://www.nus.edu.sg/corporate/rese...research12.htm

The link to the comercial site:

http://www.glofish.com

And heres a look: