Is it possible the seals are just coming back to where they once were? I mean i found/seen it first hand
http://www.nma.gov.au/online_features/goolwa_toowoomba/indigenous?result_6095_result_page=2
Note this is in the aboriginal museum down there and it states
Tanned seal skin
This seal was caught in the Goolwa channel in 1901 by the Lush family. The seal was caught in a net, and would have been in the Coorong chasing a feed. Seal was a traditional food.