Aaron Pannell of the Marlborough Mussel Company said there had been "very good growth" this season.
"The last three or four years have been quite good for us and this year in particular."
A sustainability study led by NIWA principal scientist Barbara Hayden has found that the winds and rainfall associated with the Southern Oscillation weather patterns impact on mussel growth.
The westerly or northwesterly winds of El Nino summers promote "upwelling" along the continental shelf in Cook Strait, bringing cold, deep and nutrient rich water to the surface, while La Nina's easterly or southeasterly winds promoted "downwelling".
El Nino conditions resulted in more nutrients entering the Pelorus Sound from the ocean, allowing better phytoplankton growth and therefore better fed mussels and higher yields for mussel farmers, the report found.
Source: The Marlborough Express