Shrinking salmon sizes have forced retailers such as Whole Foods to rewrite the rule book on buying salmon from wholesalers, just one of many changes seafood companies, retailers and restaurateurs are being forced to make as climate change impacts the sector, Bloomberg reported.

Scientists believe Alaska salmon are getting smaller in part because they are returning from the ocean at younger ages, but they are struggling to understand why, particularly when the run and catch are strong.

Many are pointing a finger at climate change; the journey from freshwater streams to the ocean and back again to reproduce and die makes salmon particularly vulnerable to higher temperatures and changes to the environment.