Defining the spawning needs of calamari in Port Phillip Bay video transcript
Opening – Victorian State Government logo appears.
Title appears "Defining the spawning needs of calamari in Port Phillip Bay" against scenic background of calamari swimming underwater over weed beds.
Dr Corey Green appears onscreen with background of Queenscliff Pier and vessels fishing.
"Fishing for calamari has become increasingly popular in Port Phillip Bay and around the Victorian coastline."
"Some anglers catch them for food, while others prefer them for bait."
"Regardless of their motivation, the boom in calamari fishing effort has meant fisheries managers need to know more about them to ensure the fishery remains sustainable."
Scenic images of people boating on Port Phillip Bay and anglers landing calamari back at the boat ramp.
"So, commencing in 2012, we undertook a three year study funded by Victorian recreational fishing licence fees to answer a range of questions."
Background of calamari swimming underwater as questions appear on-screen as Corey says them:
- Where do calamari breed in Port Phillip Bay?
- What time of year is important for spawning?
- And what type of bottom habitat do they prefer for egg laying?
Map of tagged calamari appears onscreen showing locations of tagged and released calamari, mostly in the southern half of Port Phillip Bay.
"We also looked at their movement patterns using acoustically tagged calamari caught from around the bay."
"So what were the results of our study?"
New tile appears on-screen with heading of 'Critical habitat and spawning variability' against background image of white calamari eggs attached to weed on the seabed.
New tile with heading – 'Critical habitats and spawning variability' (with background photo of egg cluster in spawning habitat)
"We found that two types of seagrass in particular, Amphibolis and Zostera species, were preferred by mature calamari for egg laying."
Images onscreen of different weed types with egg clusters attached.
"The distribution of these seagrasses meant that certain areas of Port Phillip Bay are much more important for calamari breeding than others."
"Spawning habitats in the south and west of Port Phillip Bay are more critical to calamari reproduction than spawning habitats in the north and east."
Map of the indicates spawning areas throughout the Bay with most situated in the southern parts.
"We also found that the southern and western areas of the Bay including Lonsdale Bight, Point Nepean, Queenscliff and St Leonards, contained more seagrass, which is the preferred bottom habitat for egg attachment."
Footage of underwater reefs with sponges and sea squirts.
"The northern spawning habitats in the Bay were characterised by more seaweed, sponges and sea squirts, and were typically home to smaller calamari and fewer egg clusters. These areas are likely to be more important for juvenile growth than for adult reproduction."
Footage of 20 or more calamari swimming underwater over weed beds.
"We analysed reproductive organs too, and found that calamari indeed do spawn throughout the year with peak spawning occurring between spring and summer."
Slow motion underwater footage of a male calamari handing over sperm, using a tentacle, to the female, just above the weed beds.
New tile appears onscreen with heading 'Movement patterns', with background of a satellite map of the southern parts of Port Phillip Bay.
Corey appears onscreen again.
"To analyse the movement patterns of calamari, 40 were caught and tagged with electronic acoustic transmitters."
Footage of divers underwater with listening stations and map of the Bay showing locations of listening stations throughout.
"73 acoustic receivers or 'listening stations', positioned around the bay at various depths, detected any tagged calamari swimming past within a 400 metre radius.
"So what did we find?"
"The maximum period a calamari stayed within the vicinity of a listening station was about 10 hours."
Underwater footage of calamari swimming, then back to Corey speaking to camera again.
"One tagged calamari travelled 51 kilometres in the southern part of Port Phillip Bay over 8 days whereas another one travelled 8 kilometres within a 24 hour period.
Underwater footage of a group of calamari swimming towards camera.
"We know calamari grow very rapidly completing their lifecycle in less than one year, but we didn't know they exhibited movement patterns like these."
Map onscreen shows movement of one calamari over one day moving from Swan Bay 4.2km to Queenscliff in the one day and then another 3.8km to Point Lonsdale the next day.
New tile with heading – 'More informed community' against scenic background photo of moored boats and coastline near Sorrento.
"This study confirmed that southern and western regions of Port Phillip Bay are particularly important during the spawning season, and that individuals are capable of moving short and long distances."
Underwater footage of calamari swimming, then an angler unloading their calamari catch by the boat ramp.
"Although high catches from spawning aggregations can occur, their biology helps to replenish population numbers quickly."
Corey appears onscreen again talking to camera.
"Thanks to this work, fisheries managers, scientists, and now anglers have a better understanding of the populations characteristics of calamari in the Bay and are now able to make more informed decisions about keeping them a sustainable fishery that's enjoyed by so many."
Photos of happy anglers holding calamari aboard boats appears onscreen.
"For more information visit our website."
Against a sunset silhouette of a man fishing for calamari appears the web address of www.vic.gov.au/fisheries
Logo appears saying 'Your fishing licence fees at work' followed by the State Government logo once more.