A number of top US grocery stores, including Trader Joe’s and Whole Foods, have pledged to reject selling the genetically engineered “frankenfish” if it is allowed on the market in April.The mutant fish was engineered by scientists at a company called AquaBounty, which has spent more than 15 years and $50 million researching and perfecting the frankenfish. The mutants can grow to market size in 16-18 months, rather than the usual 30 months required for the Atlantic salmon...