Fish of the Day
Happy Monday, everybody! Today's fish of the day is the Western blue groper!
(adult female)
The Western blue groper, despite the name, is not actually a groper, but is instead a species of wrasse! Scientific name Achoerodus gouldii, named after John Goul, a British taxidermist. Found in and around SouthWestern Australia, common from West of Melbourne, up to Perth. Although these fish once had a much larger range, this has shrunk significantly within the last 50 years, possibly due to worsening conditions along the reef, or overfishing. Their habitat is found on the Great barrier reef along the coastline, inbetween 0 to 65 meters of depth. Young fish will spend their times in closer waters, often in estuaries and river mouths, although adult fish will migrate slightly deeper. They form social bonds referred to as a "harems" made up of one large dominant male, two or more adult females, and a couple of juvenile fish. These harems hold a home range that is tightly kept, and they are territorial over.
(male)
Acting as a keystone species along the Great barrier reef, as the large and rough peg shaped teeth, as well as suction ability allows these fish to pull off reef eaters. Including but not limited to adults temporarily dislocating their jaws to consume large prey. Eating sea urchins, abalone, molluscs, and crustaceans. Including biting off chunks of algae mats, to slowly pick out the small crustaceans within. Which if left unchecked will overpredate the algae along the reef. These fish can get up to 1.7 meters in size, making them far too large for most predators. As such, only sharks and humans are large enough to predate on these once they reach maturity.
(male)
Like many other wrasse, the Western blue groper breeds in early winter to mid spring, which involves introducing milt into the female fish. Then later, these fish will swim into deeper waters to spawn, releasing larvae into the water column. All fish are born female, as this species is protogynous hermaphrodite, meaning they can switch genders later in life. Juvenile fish are marked by the green coloration, with pale spotting, although this spotting will fade away as they grow, being fully gone by 15 when reaching sexual maturity, and at a size of 82cm. After this, these fish have the ability to change sex, female to male, which can take up to 20 years if started at this stage, although older fish can transition much quicker. Female fish are smaller in size, and are known by the distinctive green coloration, although male fish are a much brighter cobalt blue. Within the set harem social hierarchy, if the dominant male fish is removed, due to predation or other death, the largest female fish can begin sex change, as early as hours after male has left. These fish can live up to 70 years in the wild, and expect more than this in captivity before passing, leaving behind many juvenile fish.
(juvenile)
That's the Western blue groper, everybody! I hope you're having a wonderful day!
(female)
