triploid trout

[Phone]

All,

 

We don't have a 'fisheries management' section. I'll put me question here in hopes of an answer - or two.

 

In another thread the trout with blue spots were thought to be "triploid". (EA stocked fish)

 

Why in the world would you want to stock triploid trout? Are they that prolific? Does the spawn attract something undesirable (i.e. crayfish)?

 

Weird, I mulled on this one all night.

 

Phone

[Steve Walker]

You would stock triploids because you do not want them to come into spawning condition or to breed.

 

In a put-and-take trout fishery, you would do this because you don't expect them to breed to keep the water stocked, and fish in spawning condition don't make good eating.

 

In a semi-wild fishery with its own indigenous breeding population of (brown) trout, you would stock triploids because you do not want your domesticated trout to interbreed with the resident stocks - the theory being that you erode the genetic diversity of the country's trout population by chucking domesticated trout in everywhere. This is the reason that triploid-only stocking is government policy for farmed fish.

[Frogger]

You would stock triploids because you do not want them to come into spawning condition or to breed.

 

In a put-and-take trout fishery, you would do this because you don't expect them to breed to keep the water stocked, and fish in spawning condition don't make good eating.

 

In a semi-wild fishery with its own indigenous breeding population of (brown) trout, you would stock triploids because you do not want your domesticated trout to interbreed with the resident stocks - the theory being that you erode the genetic diversity of the country's trout population by chucking domesticated trout in everywhere. This is the reason that triploid-only stocking is government policy for farmed fish.

 

Also spawing takes up a lot of energy so Triploids grow quicker as that energy that would normally go into spawning is not used. I think Triploid Rainbow Trout are very popular as majority of Rainbows don't spawn in this country (I think there are one or two exception waters) due to the cooler waters so this would be a massive waste of energy going into a process that is never going to happen i.e spawning.

[Phone]

All,

 

Thanks guys.

 

Beginning to get my head around it a bit. Certainly the part about disrupting the "native" fish makes sense.

 

I have to rely on what I know about (some) carp. In carp both the male and female are reproductively sterile. Frogger, carp go through the energy sapping motions - breed, have spawn - etc. It's just that the resulting spawn is sterile. It's not like being nutered(sp). Don't know anything of trout.

 

Phone

[Frogger]

All,

 

Thanks guys.

 

Beginning to get my head around it a bit. Certainly the part about disrupting the "native" fish makes sense.

 

I have to rely on what I know about (some) carp. In carp both the male and female are reproductively sterile. Frogger, carp go through the energy sapping motions - breed, have spawn - etc. It's just that the resulting spawn is sterile. It's not like being nutered(sp). Don't know anything of trout.

 

Phone

 

 

Just to clarify, diploids ('normal' fish) generally grow quicker than triploids upto a point. That point is when the onset of sexual maturity and gonad development slows the growth of diploids and triploids overtake the diploids for growth. In scientific studies it has been found that after the onset of sexual maturity Triploid Channel Catfish, Rainbow Trout and Plaice/Flounder hybrids not only exhibit faster growth but also better feed-conversion efficiency than diploids. Bieniarz etal 1997 also found that as sexual maturity approached in triploid Common Carp they grew faster than diploids.

[Phone]

frogger,

 

Thanks, cool stuff!

 

Phone