Salmon farms 'causing a stink': Tas Greens

It's salmon versus abalone in an island seafood battle where the problem is poo.

Consumer demand for the Tasmanian-grown fish is outweighing supply but plans by producers to expand the sector are facing opposition, with environmentalists claiming salmon scat and uneaten feed are polluting waterways.

The Tasmanian Abalone Council says the water is getting murky around salmon farms, leading to a reduction in the number of abalone that can be harvested.

The two industries can't co-exist and salmon should be grown in land-based farms, not in netted tanks submerged in waterways, Tasmanian Greens leader Kim Booth said on Thursday.

"No consumer is going to accept that Tasmanian salmon is cleaner and greener if they look at the ocean underneath these cages and see they are just as dirty as a pig farm or a chook farm," Mr Booth told reporters in Hobart.

Salmon producer Tassal wants to double its output by 2030 and spokeswoman Linda Sams said the company will consider a number of options for expansion.

"We're looking to grow in a sustained kind of responsible way," she told the ABC.

But Mr Booth called for a halt to granting approval for any new or expanded salmon farms until further independent research is conducted.