The signs are a joint initiative of Christchurch City Council, Crown Public Health and Environment Canterbury. They replace ones that have become unreadable over the years through vandalism and the effects of weather.

The new signs provide warnings in English and Maori that there is a health risk in eating shellfish and participating in water contact sports such as kite surfing, swimming and windsurfing.

They have been put up in seven locations: the carpark end of Rockinghorse Road, the South Brighton motor camp, the Pleasant Point Yacht Club picnic area, Humphreys Drive, by Scott Park, the boat ramp at Redcliffs end of the causeway and Moncks Bay.