"What we found is that there isn't enough certified sustainable seafood, such as by the Marine Stewardship Council, to meet that demand," said author Natalie Ban, marine ethno-ecologist at the University of Victoria.
"Instead what we are seeing is that some of these big retailers are moving towards what are called fishery improvement projects."
In principle, Ban says, these projects are a wonderful notion because big companies, like Walmart, are making the commitment to sell only sustainable fish.
"But what is happening is that a lot of [these companies] are stuck in the very early stages of developing a plan on how they might improve the fishery and they get market access for that," said Ban.
"So they are considered sustainable even if they just have a plan that they haven't yet implemented."
Consumers want sustainable fisheries
"On the other hand it is really great news consumers want sustainable seafood," said Ban.
"These fishery improvement projects haven't been in existence for that long, so now is a great time to really make some work."
Ban says improvements can be made, such as industry wide standards for what is considered sustainable seafood, and an independent monitor to ensure fisheries are following through on their commitments to become sustainable.
"Otherwise, if it is the fishermen themselves or the retailers, they may have too much of a vested interest to be able to do a transparent job."
To hear the full interview, listen to the audio labelled: Rising demand for sustainable seafood