The Abalone Ranched by OGA
Firstly, large broodstock Greenlip abalone are carefully harvested by licensed professional abalone divers affiliated with our company in the pristine waters of Flinders Bay. Those abalone are then transferred to the 888 Abalone hatchery in Bremer Bay. They are placed in tanks in a secure quarantine facility for breeding purposes.
The abalone are then encouraged to spawn by running UV irradiated water of the tanks holding the abalone. This causes the abalone to eject the eggs or sperm into the water.
The hatchery technicians then carefully siphon out the eggs from the female spawning tanks, remove some sperm from the male spawning tanks and mix the two in the correct ratio to achieve fertilization. Over the next 7 days the eggs develop into a larval stage called veliger.
After approximately one week to 10 days the veliger metamorphose into post- larval spat. It is just before the veliger become post-larval spat that they are placed into settlement tanks. Settlement tanks are comprised of many thin plastic sheets that are specially prepared to have a fine coating of microscopic algal film on them. This microscopic algae has chemical cues that cause the veliger larvae to metamorphose and settle on the carefully prepared plastic plates.
Microscopic algae called diatoms are encouraged to grow on these plates, which form the diet of those grazing juvenile abalone until they attain a length of 15-20mm.
The small abalone are then removed from the settlement tank sheets and then placed into tanks that are approximately 500mm deep, have a sloping bottom and contain a number of concrete bricks called hides. The abalone at this small stage are very cryptic and prefer to hide under the concrete hides. The abalone are then cultured in this system and fed an artificial diet until they reach a size of approximately 40mm.
Once the abalone are approximately 40mm in length they are large enough to be transferred to the OGA abalone ranch in Flinders Bay, Augusta. At this size they are able to protect themselves from many predators such as fish by contracting the foot muscle down tightly on the shell. They are ready for their new life living on the purpose built reefs we have built for them on our leases in Flinders Bay.
We carefully remove them from the 888 Abalone tanks, place them into release units and transport them to Augusta. Once they arrive our divers meet the abalone transport truck and quickly place the abalone on-board tanks in our dive vessels and dive on the reefs to attach the release units containing the baby abalone to our reefs. After 2 days the abalone are settled from the stress of the transfer and the ends of the release units are removed which allows the abalone to crawl out of the release unit and make their home where they prefer on the reef we have created for them.
Over the next 2-3 years the abalone feed on passing drift weed and make their home on the reefs they have been placed on. Nature takes care of all their nutritional requirements for growth and vigor. Our unique abalone ranching system produces abalone of the same high quality as that harvest by divers in the abalone quota fishery. Depending on the requirements of our customers the abalone are harvested by our divers at a length of 100-140mm.