03 Jul 2013
A blue marlin that washed up on a souA blue marlin that washed up on a southern Adelaide beach last week may be the first recorded sighting in South Australia.
Measuring 3.2m to the tip of its bill to tail and weighing approximately 250kg, the discovery of the typically tropical and subtropical fish was reported to Fishwatch last Wednesday.
The big fish was found midway between Carrickalinga South and Normanville.
A coordinated effort by Primary Industries and Regions South Australia and Department of Environment, Water and Natural Resources officers was required to transfer the marlin to researchers at the South Australian Research and Development Institute (SARDI) for investigation.
It was extremely rare for billfish to be sighted in South Australian gulf waters, as they are usually found in warm tropical and subtropical oceanic and shelf waters, Dr Paul Rogers, SARDI researcher said.
“The blue marlin is a large, highly migratory pelagic species that is usually found in waters off eastern and western Australia, and can range as far south as Tasmania depending on the current and water temperatures that are broadly influenced by El Nino and La Nina events,” Dr Rogers said.
“Blue marlin typically spend their time in warm surface water layers that form above cooler bottom water and it’s likely it followed the warm Leeuwin Current that originates in the Indian Ocean off Western Australia.
“It’s likely the Marlin became confused by the geographical barriers formed by Eyre Peninsula and/or Kangaroo Island, and subsequently moved north where it succumbed to the colder South Australian gulf waters.
“Routine examinations will be conducted using samples taken at SARDI Aquatic Sciences to rule out the possibility that it died from an infectious disease.”
The rare find will be on display at the SARDI Aquatic Sciences Open Day on Sunday 17 November.
In June a record 4.4m blue marlin washed up on a beach east of Albany in Western Australia in June. This area is considered to be the southern extremity of the Marlin’s typical migratory range in that region.
To register a sighting visit www.redmap.org.au
SARDI scientists will work with SA Museum researchers to conduct further investigations and the find will also be recorded on Redmap.