National Parks and Wildlife Service SA (NPWSSA) has deployed three buoys marking part of the outer boundary of the Kellidie Bay Marine Park Sanctuary zone.
The buoys are yellow in colour and are positioned on three of the four GPS reference points that outline the boundary.
NPWSSA senior ranger Lana Roediger said the buoys were deployed to provide a visual aid to help fishers navigate the sanctuary zone boundary.
"The shape of the sanctuary zone can make it difficult for fishers to know where the boundary is," she said.
Boaters should not rely solely on the buoys to determine their position and are encouraged to use navigational equipment for accurate locations when fishing in the area.
Vessels are free to move within the sanctuary zone but they cannot engage in any fishing activity.
"No part of a fishing activity can occur within a sanctuary zone, which means a vessel cannot move into a sanctuary zone to land a fish that was hooked outside of the area," Ms Roediger said.
Kellidie Bay is the only sanctuary zone in the area where buoys are positioned on the boundary.
"There are six Marine Park Sanctuary Zones around Coffin Bay, it is important that all water users are aware of the zones and the rules which apply," Ms Roediger said.
Signs are displayed at the Coffin Bay and Dutton Bay boat ramps which show the sanctuary zone areas. Additional maps and information can be found at marineparks.sa.gov.au.
Sanctuary zones are designed to protect the habitat marine species use and provide a safe and healthy refuge that allows them to breed undisturbed.