A cadre of recreational ocean users and water-sport business owners demonstrated Saturday afternoon in opposition to a proposed expansion of the Hawaiian Islands Humpback Whale National Marine Sanctuary.

Bearing signs that read "No Fishing?" and "Say No to NOAA" — referring to the National Oceanic and Atmospheric Administration — protesters lined Kalanianaole Highway in Hawaii Kai.

Introduced in March, the NOAA proposal called for increasing the size of the sanctuary by 17 percent and expanding its focus to the protection of all marine species within its boundaries.

Demonstrators expressed concern that the plan and its associated regulations would unduly restrict recreational ocean use and negatively affect businesses that operate in coastal areas.

Frazer McGilvray, executive director of Malama Maunalua, a nonprofit group dedicated to restoring and protecting Maunalua Bay, defended the proposal.

"The decline of Maunalua Bay is serious — the worst in the state," McGilvray said in a statement released Saturday afternoon. "NOAA’s proposal represents an opportunity to protect and restore the bay, ensuring this beloved ecosystem survives for the enjoyment of our children and their children."

McGilvray emphasized that the changes would not affect normal ocean activity.

Public comments are being accepted through Friday. For more information, visit 808ne.ws/1QwA7o8.