Government Plans to Supersize Trout

The federal government announced yesterday it has developed an improved genetic method to supersize supermarket trout.

The trick is to strip the fish of their sexual cravings.

William Hershberger of the USDA’s Agricultural Research Service (ARS) leads a team working to develop a more efficient way to produce rainbow trout with three sets of chromosomes rather than the standard two.

Trout with three sets of chromosomes grow faster, so the industry regularly tries to breed fish with three sets. Trout with three sets are unable to reproduce, so all the energy from food is shifted from reproduction to growth.

Here's how it's done:

Trout normally have two sets of chromosomes. Scientists first create trout with four sets by applying pressure to the embryos during early development. Then they cross those with regular trout and generate fish with three sets.

The process is painstaking and doesn't always work.

Hershberger and his group have fine-tuned the procedure and can more reliably produce trout with four sets of chromosomes, which then allows generation of the desired three-set type.

Lest you falsely thought your supermarket trout was usually wild, the ARS says the fish-production industry has already been enlarging trout.

And, the scientists say, you are behind it all.

Consumer demand for an 8- to 10-ounce filet has driven the marketable trout size from one pound to almost two pounds and rising, according to the ARS.

Since the three-chromosome-set fish are sterile, scientists trust no genetic interaction with indigenous stocks can occur.

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-- LiveScience Staff

Image Credit: Ken Hammond, USDA