As the eggs rot, they produce hydrogen sulfide and a foul odour. The strength of the odour depends on how many eggs wash up on the beach, which depends on the timing of high tides and storm events. Odours can sometimes be detected for kilometres.
While spawning peaks in March, the odours can linger until June. The wind direction in this area is often onshore, which carries the odour towards the Island Highway and French Creek Pollution Control Centre. Each year, the French Creek Pollution Control Centre receives phone calls from residents inquiring about the odour. The Regional District of Nanaimo would like to reassure residents that the odour is the result of the herring spawn and will subside in the coming weeks.
Sean De Pol,
Manager, Wastewater Services,
Regional District of Nanaimo