The majority of eco-labels awarded to farmed fish fail to deliver the promised environmental benefit, according to results of a study released by researchers at the University of Victoria.

Most of the industry and government certifications for finfish aquaculture products offer only a negligible benefit to the environment when compared with conventionally farmed fish, according to the analysis.

"From a consumer point of view, there is a perception that [an eco-labelled] product offers a significant improvement in performance over the conventional product," said lead author John Volpe, a UVic marine ecologist. "On the whole, the benefits associated with those claims are quite modest."

Organic certifications, such as the Soil Association eco-label, performed best in the analysis, offering a substantial benefit to the environment over conventional farmed fish.

The study, titled How Green is Your Eco-label?, evaluated the standards of 20 eco-labels based on 10 environmental criteria. They ranged from the use of antibiotics and sustainability of feed to pathogens released and the effects of farmed fish that escape into the environment.

"Most eco-labels for farmed marine fish offer no more than a 10 per cent improvement over the status quo," Volpe said.

He said even labels that have won consumer confidence ignore some environmental effects.

Moreover, the certification bodies do not share monitoring data that would assure consumers that the products are better, he said.

The researchers used data derived from the 2010 Global Aquaculture Performance Index to determine the environmental performance of eco-labelled farmed finfish, such as Atlantic salmon, cod, turbot and grouper.