The other, taken from a chinook salmon, is a version of the growth-hormone gene itself.

So could the disappearance of Chinook salmon from the waters off California and Oregon last year; the population during the spawning season was 88% below its all-time high in 2003.

The combination of Chinook and ocean pout genes allow the AquAdvantage salmon to produce growth hormone all year round, so it grows incredibly quickly.