Researchers have made an aerial survey of how many southern right whales might be along the South Australian coastline.

Their check found 35 whales, including 11 calves, in the seas between Ceduna on the west coast and the Victorian border.

Saras Kumar from the Environment Department said it would form part of a long-term study of population size and distribution of whales.

"The idea is that it gets done annually and then we can actually see which areas the whales are using and actually see whether the population's increasing, as it has been in the south-west, but in this kind of south-eastern part of Australia the numbers aren't as high," she said.