Water Temperature a big cue to Snapper Migration

30 October 2017

Snapper fishing in Port Phillip Bay is sensational this time of year. A recent study by fisheries scientists has revealed that the peak annual spawning migration of snapper into the bay occurs when the water temperature reaches 15°C, which tends to happen in October and did so last week.

Victorian Fisheries Authority (VFA) CEO Travis Dowling said the snapper tracking study, which was funded by recreational licence fees, used electronic tags to monitor the movement of snapper over time.

"The study showed the majority of snapper migrants should be in the bay by now, and it was just a matter of anglers finding them and hoping they were hungry," Mr Dowling said.

"Anglers targeting snapper can expect an improvement in fishing this year as several new groups of fish enter the adult and 'pinky' fisheries.

"Annual surveys by VFA scientists indicate that spawning success was reasonably good in the late 2000s. Fish originating from those spawning seasons will be prevalent in the smaller size range of the adult fishery this season, around 2-3 kg.

"Furthermore, very good spawning years in 2013 and 2014 should see a major boost in the catch rate of smaller 'pinky' snapper up to 35cm in Port Phillip Bay and Western Port.

"VFA scientists have undertaken surveys of juvenile snapper in Port Phillip Bay annually for 24 years and know to expect variation in spawning success depending on environmental conditions.

"Port Phillip Bay is an important spawning and nursery area for snapper and these surveys tell us about future replenishment of the 'western snapper stock', which extends from Wilsons Promontory to southeast South Australia.

"It's important to monitor these unpredictable fluctuations to inform the sustainable management of the snapper fishery.

Mr Dowling said it takes three to four years for snapper to reach 28cm, the legal minimum length in Victoria, and typically six to seven years to enter the adult fishery at 40cm. "Based on the last decade of survey data, scientists expected catch rates to drop during the last few years compared to the peak experienced about 6-7 years ago. Their surveys of anglers at boat ramps confirmed this, with a decrease in catch rates of large snapper reported from 2014.

"However, the future trend for the snapper fishery is expected to be a moderate increase before stabilising into the early 2020s."

Mr Dowling said it was important that all anglers abided by snapper bag and size limits to ensure a high quality fishery that is best able to accommodate the natural fluctuations in spawning success."