For the very first time, Australian and New Zealand scientists have successfully identified the tiny larva of the giant Bump-head Sunfish (Mola alexandrini).
Dr. Marianne Nyegaard, a sunfish expert from the Auckland War Museum, together with Australian Museum scientists, Kerryn Parkinson and Andrew King, made the significant discovery in the Genomics Laboratory in Sydney.
The giant Bump-head Sunfish is one of only three Mola species found in Australian waters.
This new breakthrough has provided some really important information that is helping scientists to understand the life cycle of these beautiful marine beasts and how to better care for the environment that we continue to exploit.
Dr. Nygaard said:
“This is the first time we have been able to genetically identify a Mola alexandrini larval specimen anywhere in the world,”
The specimens were collected off the NSW coast in 2017 and Dr. Nyegaard, a world leader in sunfish genetics was called to identify them.
Dr. Nygaard explained that larval fish, more often than not, look nothing like their adult counterparts. Sunfish larvae are no exception and she explained that none of the features used to identify the adult sunfish are visible in the minute larval specimens. This often makes the identification process particularly hard.
“Despite this, using the resources of the Australian Museum’s Genomics Laboratory, we were able to conduct DNA analysis on one of the specimens which was preserved in alcohol.”
The extremely rare larval specimens are only around 5 mm in length and the utmost care is needed to prevent damaging the delicate little things.
Kerryn Parkinson from the Australia Museum’s Ichthyology division had the task of painstakingly removed a single eyeball from the specimen. Andrew King was the chief genomics specialist who conducted the DNA extraction and analysis.
Professor Kris Helgen, Chief Scientist and Director of the Australian Museum Research Institute (AMRI), said this research is an important lesson in the value of museum collections.
“These molecular-level descriptions of the world’s biodiversity provide us with a deep understanding about different species, and their eggs or larvae,”
“This raw data can give us answers to questions about little known or rare species and provide information about their conservation and management,”
Parkinson said the sunfish has attracted international interest because of their unique shape and large size.
“These beautiful giants of the sea are found worldwide in the open ocean of tropical and temperate seas. The classification of the species from the genus Mola has long been confused, despite the large amount of interest these fishes create. This is mainly due to their rare occurrence to scientists, and difficulties in preserving them for research,”
Dr Nyegaard explained that the giant sunfish hold the record of the highest potential egg capacity of any vertebrate; 300 million of them in a 1.5 m long female ocean sunfish!
This adds more mystery to the fact that they’ve never been documented in the wild before.
“If we want to protect these marine giants we need to understand their whole life history and that includes knowing what the larvae look like and where they occur,”
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