In the mid 1980s researches at the University of Maine and the University of Washington developed ways of inducing triploidy in oysters. They treated newly fertilized eggs with chemicals, heat, and pressure-shock, to coax the eggs into retaining an extra set of chromosomes.

The resulting triploid oysters, if they survive the treatment, grow faster and larger than diploids, primarily because triploid oysters are reproductively sterile. As such, they put all their energy into growth instead of reproduction. Sterile triploid oysters are marketable year around, even in the warm months when diploid oysters become "spawny".

The induction method of producing triploid shellfish has been used commercially since around 1985, mostly with the robust Pacific Oyster (Crassostrea gigas) on the U.S. West Coast.

To induce triploidy, millions of newly fertilized eggs are treated to inhibit the formation of the 2nd polar body, trapping the genetic material in the eggs.

As a result, the egg contributes two sets of chromosomes instead of one, and the haploid sperm from a diploid male contributes another set, creating a triploid zygote.

Triploid shellfish induced by this method typically result in only about 80% of the viable eggs successfully becoming triploid.

Mortality losses of 50% to 70% in the first 4 days of life are common due to the harsh treatment.

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