Researchers were due to leave for the Great Australian Bight last Thursday night with the mission of tagging several thousand southern bluefin tuna.
The tagging is part of ongoing monitoring of tuna stocks undertaken by the Commission for the Conservation of Southern Bluefin Tuna (CCSBT) with the actual tagging being done by researchers from Australia's science agency.
The CSIRO researchers this year contracted Australian Fishing Enterprises and the vessel Emma J for its two 15-day tagging sessions, the first of which took place in December.
Fisheries researcher Thor Carter said this latest trip would entail placing 35 computer tags into the bellies of tuna with the tags able to record different data, including temperature inside and outside the fish as well as rough idea of latitude and longitude based on the hours of daylight.
This data was archived in the tags that hopefully would be forwarded to scientists once the fish had been caught so the movements of tuna could then be analysed.
Researchers also hoped to place conventional or simple marking tags consisting of a thin strip of plastic complete with individual serial number on about 5000 fish.
Any commercial or recreational fisher catches a tuna with a conventional tag should return it to the address on the tag thereby being eligible for a free CCSBT t-shirt or cap.
Fishers must remember to record details on where and when they caught the fish and how big it was.
The more valuable computer tag has a return reward of $250.
Juvenile tuna tagged in the Great Australian Bight have been caught as far away as New South Wales and South Africa.
Tagging this month will primarily take place as far west as Ceduna and the Nuyts islands where the youngest fish are present, while researchers also want to avoid tagging in the same area where fishing boats are active to prevent freshly tagged fish from being caught straight away.