An enormous and incredible fish, the Queensland Grouper is Queensland, Australia’s aquatic emblem. Capable of attaining lengths greater than nine feet and growing to weigh more than half a ton, these are the largest bony fish living in coral reefs, and can be found throughout the Indo-Pacific region. Sometimes called Brindle Bass, Bumblebee Groupers, Brown Spotted Cod, or simply referred to as Giant Groupers, these fish are a favorite with divers from all over the world. Let’s take a closer look.
Queensland Groupers: The Basics
Juveniles look much different than adults; they have irregular yellow and black markings and are often caught for the aquarium trade. Like their close relative, the Malabar Grouper, these fish change color as they age. Mature Queensland groupers are greyish green to brown in color, with a splotchy look that helps them to blend in with their surroundings. The fish have large mouths and rounded tails, plus two dorsal fins, the first of which is larger than the second and contains spines. The fish’s fins and tail are covered in little black spots.
Capable of opening and closing their mouths with so much force that it sounds as though a firecracker has gone off underwater, Queensland groupers are one of the few fish species which vocalize, vibrating their air bladders to communicate with other animals via a loud bellowing noise which is thought to be a form of territorial marking. Still, they form partnerships with other animals, such as trumpetfish, which hide by swimming near the grouper, sticking to the confines of its shadow. When prey passes, the trumpetfish darts away from the grouper to capture it.
Groupers themselves eat very quickly, sucking in prey, smashing it with heavy crushing plates inside the pharynx, and then swallowing it whole. If you ever see a grouper eat, the entire process happens so quickly that it simply looks as though the animal they have consumed has disappeared; this normally happens at dawn and dusk, as this is when the groupers are at an advantage over the fish, octopus, sharks, and small turtles that they consume.
Capable of living for decades, Queensland groupers are protogynous hermaphrodites, which means that they emerge from their eggs as females, and are capable of transforming themselves to males once they reach sexual maturity. The fish travel for long distances of hundreds of miles to find a suitable mate, and in some cases, the largest of a group of females will transform herself into a male in order to spawn with the rest of the group if no male arrives to do the job. Most of the time though, the groupers will meet up en masse, with thousands of fish descending on a certain site, spawning, and then heading back to their homes.
Diving With Queensland Groupers
If you’re able to dive the Yongala, you might encounter one of the resident groupers, a mammoth of a fish called VW in honor of his size, which is comparable to that of a Volkswagen Bug. This is just one of the many places you can find the species; they are located in reef habitats and at wrecks all throughout the Indo-Pacific, particularly in the warmest areas of the Pacific, Indian Ocean, and Red Sea. While they are a rare sight in New Zealand, they are sometimes found in northern waters during the warmest months of the year. Most at home in depths between 10 and 25 meters, they are capable of living in water up to 100 meters deep.
Bold and curious, these giant groupers are not known to attack; however, they are large enough to knock a diver out of the way, and some who have hand-fed the animals have sustained crushing injuries to their hands and arms. Normally lurking in the hiding places they dig out for themselves beneath large rocks, or secreting themselves in cracks, caves, and crevices, the fish can be hard to see. Some resident groupers are used to divers visiting them, and will come out to say hello when they hear bubbles. Others, particularly those which have been fed, will follow divers around to the point of becoming a nuisance.
The largest groupers have virtually no predators other than sharks and the occasional fisherman; younger animals though, are at risk due to the aquarium trade. Their beautiful colors make them a target, but once they are placed in a home tank, they quickly outgrow it. In one famous case of a Queensland grouper named “Bubba”, a pet owner dropped him off at Chicago’s Shedd Aquarium, leaving him in a bucket on the front steps with a note explaining that he had become too large to be cared for properly. The fish was put out on the stoop in 1987, and lived at the aquarium until his death from cancer in 2006, nearly twenty years later. The aquarium’s veterinary staff tried to save him by providing him with chemotherapy, however attempts were unsuccessful. He weighed 154 pounds at death; only a fraction of the size of some of the largest wild Queensland groupers ever recorded.
Overfishing has caused the Queensland grouper population to plummet in areas where these groupers were once abundant, as the fish is a popular catch. Commercial fishing operations targeting groupers have been severely limited today however, and groupers are being raised on farms for consumption in an effort to protect the wild population from further decline. In addition, the Australian government has effected several different regulations in an attempt to stop human predators from causing numbers to decrease in the future. There are bans on grouper fishing in New South Wales, and collection for the purpose of selling the fish for pets is also forbidden. It is hoped that the population will return to health after a period of concentrated conservation efforts.
If you have the opportunity to dive the sites where these monster fish are most often encountered, be sure to bring your camera and your favorite dive buddy with you; you’re certain to be captivated, amused, and amazed by the fish, both due to its appearance and due to its intriguing personality.