The opening of the recreational scallop season is being celebrated with the annual Whitianga Scallop Festival taking place this Saturday September 10.

The season for Northland, Coromandel and the Bay of Plenty opened September 1, amidst tsunami warnings triggered by a 7.1 earthquake off the East Cape.

Daily bag limits are 20, and minimum size is 100mm. A piece of 100mm plastic pipe is suggested as a good gauge for divers.

The minimum legal size for scallops in the Auckland and Kermadec area is 100mm measured across the widest part of the shell.

The legal bag limit for scallops is 20 per fisher per day.

In addition, divers may take an extra bag for each of up to two people on board a boat, provided they are acting as safety people for the divers, says a statement from the Ministry of Primary Industries.

When dredging for scallops, only those actively involved in fishing are entitled to a daily bag limit.

Fishery Officers and Honorary Fishery Officers will be patrolling and inspecting scallop catches, says the statement.

Fines of $250 to $500 per offence can be imposed on fishers who ignore the rules. Serious breaches can result in confiscation of diving gear, boats and vehicles.

All shellfish to which a minimum size restriction applies (including paua, scallops and dredge oysters) must be landed in the shell and cannot be shucked or shelled seaward of the mean high-water mark. This includes transporting on the water.

Undersized scallops must be returned to the water immediately. To give them the best opportunity to survive they should be returned to the same place that they were taken from.

Any scallops eaten at sea form part of the daily limit. Any scallops not eaten must be landed in the shell. Divers are entitled to one bag limit per day, whether eaten on board or not.