OSLO, June 25 (Reuters) - The volume of salmon in cages at Norwegian fish farms, as measured by weight, rose by 6 percent year-on-year in May, industry lobby group Seafood Norway said in a statement.
Also known under the term biomass, the quantity was estimated at 628,000 tonnes of salmon, down from 635,000 the previous month, it added.
Seafood Norway represents about 500 Norwegian seafood companies.
Big Norwegian salmon producers include Marine Harvest MHG.OL , Leroey LSG.OL , Salmar SALM.OL , Grieg Seafood GSFO.OL and Norway Royal Salmon NRSM.OL .
Norway is the world's top salmon producer, followed by Chile.
In April, salmon biomass was up 5 percent year-on-year and in March year-on-year growth was 4 percent.