SEAWEED

The Monterey Bay Aquarium, in the framework of its Seafood Watch program, gave a high score of 7.9/10 to cultivated seaweed in 2014. It considers it to be one of the best choices in environmentally responsible consumption.¹

In China, in Sanggou Bay, a study² demonstrated that large-scale kelp farming had little impact on the sea-life environment. Another study³ suggests that areas of intensive kelp farming contribute to reducing the local availability of inorganic nitrogen and of dissolved phosphorus. In other words, they seem to slow the phenomena of eutrophication (accumulation of organic debris that can bring about a considerable reduction in available dissolved oxygen) and of ocean acidification.

In intensive aquaculture, the breeding of animals in a monoculture (e.g., the breeding of Atlantic salmon) has the disadvantage of comprising at one and the same time a source of CO₂ emissions, of organic molecules and of nitrogenous molecules in the environment, notably in the form of urea and ammonia.

A new way of thinking is emerging in the industry, one that involves encouraging the development of an integrated multi-trophic aquaculture⁴ combining a number of ecologically complementary species.⁵ In this new economic model, seaweed farming has an important role to play, since it produces oxygen and captures CO₂ along with inorganic nitrogen (NO₃, NH₄) and organic nitrogen (urea). It has already been mentioned that in China the co-cultivation of shellfish and seaweed improves growth and quality performances in both productions.⁶