This research aims to learn more about movement and behaviour of swordfish and the post-release survival of fish caught in the newly emerging day time deep-drop fishery off the NSW coast. Tagging is being carried out by using experienced anglers to deploy 10 pop-up satellite tags into swordfish caught during 2019/ 2020 in NSW waters.
Pop-up satellite archival tags (PSATs) are used to track the movement of marine animals, particularly highly migratory species such as sharks, tuna and billfish. The tags are like mini computers that are externally attached to the fish and travel along with the fish whilst logging information on water depth, light levels and temperature, and gathering information on its location (geolocation). This allows us to gain a greater understanding of the behaviour of the fish, their migratory patterns and catch and release survival. The great benefit of satellite tags is that they do not have to be retrieved to collect the recorded information. After a predetermined time (twelve months) the tag decouples from the fish and ‘pops-off’, floating to the surface. The tag then transmits the data that it has stored whilst it has been underwater to orbiting satellites that pass overhead. This data is then relayed back to DPI.
The project will provide us with data on the exciting new recreational fishery including information on the timing and availability of swordfish in NSW, whether swordfish tend to return back to the same grounds seasonally and their suitability for catch and release. DPI is undertaking the project with the Australian National Sportfishing Association (NSW) and NSW Game Fishing Association.
This project also includes the “Great Swordfish Race” which plans to provide an interactive experience to improve our understanding of the mystical and iconic “gladiator of the ocean” along the east coast of Australia and foster angler stewardship in this new fishery.
Once the first fish has been tagged, the race will be underway for the individual swordfish that travels the furthest distance whilst tagged.
We will keep you updated on the Race and the broader project on this page and on the DPI Fisheries Facebook page, including when fish have been successfully tagged. Information on movement of the fish will be provided when the tags pop-off the fish and their movement data is streamed back to us via satellite.
The new method of deep dropping for swordfish has revealed that swordfish are now more accessible than ever before to recreational fishers along the east coast of Australia. It is important that we learn more about this fishery, to enable it to grow and maximise its potential whilst ensuring the sustainability of the fishery is maintained.
The project will:
The data from this project will be used as part of a larger project being undertaken by Dr Sean Tracey of the Institute for Marine and Antarctic Studies (IMAS), Hobart, with similar objectives completed in Tasmania and currently underway in Victoria.
Stay tuned for more information.
|Tag Ref.||Skipper||Date deployed||Location||Date pop-up||Location|
|NSWSword#1||Chris Cleaver||24/04/2019||South Sydney||30/07/2019||Dampier Ridge - west of Lord Howe Island|
The depth data shows that the swordfish carried out the well established diurnal pattern of diving deep during the day (around 400 - 600m+) and rising near to the surface at night. There appears to be some change to the behaviour around the end of May, where the daytime dives don’t go as deep (150 – 300m+) before the normal dive pattern to 500m+ resumes. You can see the surface water temperatures were relatively high at around 24 degrees when the fish was first tagged off Sydney and they steadily drop off to around 19 degrees when the tag popped off west of Lord Howe Island. The fish headed south towards the south east corner of Australia before it meanders eastwards and then heads on a more northerly bearing.