Tuesday March 12, 2012. Mission Blue
Everything about the goliath grouper is extreme: its size, its personality, and especially its sex life.
Once a year, schools of goliath groupers converge under the full moon and engage in a one-shot mating frenzy. For divers and scientists, this titillating event is the ultimate form of nature voyeurism, and might be key to spreading the word about the critically endangered species.
“They are indeed crazy,” marine biologist Sarah Frias-Torres of the Ocean Research and Conservation Association commented about the grouper’s elaborate mating rituals. “It’s like fish porn.” She added that no one has managed to catch the act on camera yet.
To engage in this courtship extravaganza, the fish return en masse to the reef site where they first copulated. As the courtship begins, males change from their typical blotchy patterns into a deep, provocative black, while females turn a dainty pale grey. To show off their bravado to the ladies, males often spar, ramming their heads into one another and bellowing out deep booming sounds of roughly 160 decibels—the same volume generated by a jet engine. While the macho rumble goes on, females swim by, watching.
Footage of a goliath grouper spawning aggregation at the Zion wrecks off Jupiter, Florida. This spawning aggregation was fished to extinciton in the 1980s, but in 2005 divers reported seeing the giant fish gathering again during the late summer spawning season. Credit: Sarah Frias-Torres