Aussies have had their fair share of interesting beach finds but one recent "long" and "squishy" discovery left a woman perplexed, with a marine biologist later calling her "lucky" for coming across it.
On Tuesday a beachgoer at Byron Bay found an unknown object which appeared to have two prongs and an enlarged bulging top, likening it to a tooth online. However, unlike a tooth, the discovery was 30 centimetres long.
"Does anyone know what the heck this is?" she questioned, admitting she had no idea.
'Lucky' find for relatively 'common' fish
The unknown discovery was identified as a swim or gas bladder which once belonged to a porcupinefish, which are "common" around Australian coasts.
They are a crucial organ which enables fish to adjust to the water pressure as they swim at varying depths. Just like a scuba diver uses a buoyancy compensation device attached to their tank to alleviate water pressure, fish have their very own internal method of compensating for it.
"In bony fishes, such as the porcupine fish, they have a bladder of gas that's just under the spine," Associate Professor Ian Tibbetts from the University of Queensland told Yahoo News. "What happens is when fish move into deeper water, the volume of oxygen in that swim bladder decreases, which makes them neutrally buoyant."
He explained this is why you often see fish "hanging around the aquarium in the same spot making minor movements".
The complexity of the organ is thanks to a long evolutionary process, with Tibbetts calling the woman "lucky" for seeing one up close and personal.
Swim bladders have multiple functions
Not only do swim bladders help fish achieve "zero buoyancy", they also assist with mating and defence against predators.
"They're also used for sound amplification," Tibbetts said, saying it can attract mates and often intimidate predators.
The wall of the swim bladder is made of collagen which makes the inflated organ as strong as "plastic", meaning it would long be preserved after an animal decomposed.
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