What Is An Endemic Species?
A global biodiversity hotspot, the Great Southern Reef is home to many species found nowhere else on the planet
Endemic Species (def.)
Species of plants and animals which are found exclusively in a single defined geographic location.
Harlequin fish by Scott Bennett Great Southern Reef Foundation
Unique species of the GSR
Australia's Great Southern Reef (known as the 'GSR') is home to thousands of unique marine species that are found nowhere else on earth - and scientists believe that there are still tens of thousands yet to be found and studied.
Let's take a peek at just a few...
Australian Sea Lion at Kangaroo Island by Stefan Andrews Original Source: @ocean_imaging
Australian Sea Lion
Meet one of the rarest animals in the world.
A rare beauty
The entire Australian sea lion
population lives along the southern and western coastlines of the Great Southern Reef with about 85% living in South Australia and the other 15% in Western Australia, and they are the only endemic pinniped in all of Australia.
Fin footed
Seals and sea lions are marine mammals called pinnipeds
(meaning fin footed). Sea lions can be distinguished from seals by the small flaps for outer ears.
They are recognisable by their short blonde or ash grey fur, creamy coloured underbellies, short flippers and bulky body.
Specialised ocean hunters
Agile in both the water and land, sea lions can hold their breath for up to 12 minutes. Known as benthic foragers, they feed from the sea floor on species like cuttlefish, lobsters and rays.
Their complicated breeding cycle makes them a vulnerable species.
Australian Sea Lions at Pearson Island, South Australia Great Southern Reef Foundation
Weedy Seadragon in Golden Kelp by Stefan Andrews Original Source: @ocean_imaging
Weedy Seadragon
A charismatic creature, the weedy seadragon's appendages resemble the kelp fronds found in their habitat.
Distinctive dragons
The weedy seadragon’s leaf-like appendages resemble the swaying kelp fronds found in their habitat. They drift gracefully around seaweed beds and seagrass meadows relying on camouflage and stealth to approach their unsuspecting prey.
Despite its charismatic nature, few studies on the Great Southern Reef’s weedy seadragon have been published.
In 2021, in a first of its kind study by Klanten and colleagues, it was proposed that there were four genetically distinct populations of weedy seadragons along the GSR.
Lifecycle of the weedy seadragon. Juvenile to Adult Great Southern Reef Foundation
Port Jackson Shark (Heterodontus portusjacksoni) by Gergo Rugli Original Source: www.rugliphoto.com
Port Jackson Shark
The Port Jackson shark
is a nocturnal, bottom dwelling ‘bullhead’ shark endemic to the Great Southern Reef
The shark's territory is habitually on or near the sea bottom, which is also its feeding area. They use the seagrass areas to camouflage with their pattern markings.
Port Jackson sharks are a nocturnal species and are most active right in the middle of the night.
These sharks have a small mouth containing small molar-like teeth in the rear of the mouth to crush prey which may be urchins, crustaceans, molluscs or small fish.
Port Jackson Shark by Stefan Andrews Original Source: @ocean_imaging
Annual migration
These sharks will congregate in large numbers in shallow waters in late springtime to mate. Males arrive first in harbours and bays and females usually arrive weeks later.
Mating involves biting, with the male grasping the pectoral fin, dorsal fin or flank of the female
Blue Groper by Gergo Rugli Original Source: www.rugliphoto.com
Blue Groper
The GSR supports both eastern and western blue groper. The separation of the two species can be traced back to the Ice Age, when waters became cooler and the blue groper population likely split and moved up the west and east coasts.
A large bony fish, they can grow to be up to 1.7 metres in length, and are not fully grown until they are about 30 years old. Even though they are called a ‘groper’ they are actually a large wrasse.
Blue Groper by Stefan Andrews Original Source: @ocean_imaging
Female first
These gropers are what is known as a protogynous hermaphrodite
, meaning the entire species begins life as a female and some, but not all, change sex to males later in life.
Females reach sexual maturity at about 15 years, but the change from female to male can take up to 35 years. This change usually occurs when they reach around 82cm in length and their colour changes from green to blue.
Blue Groper by Gergo Rugli Original Source: www.rugliphoto.com
Sheriffs of the Reef
Considered a keystone species, blue gropers are an important part of the marine ecosystem.
Sydney harbour's incredible marine life revealed by Reef Life Survey divers Great Southern Reef Foundation
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