Day 10: Journey to Cuba's underwater Eden
You sexy thing!When goliath groupers aggregate to spawn, males are said to emit deep booming sounds of roughly 160 decibels – the same volume generated by a jet engine.Photo by: Fausto De Nevi Herrera
If you think goliath behavior is risqué……it gets even kinkier. Black grouper start out as females, then at some point switch gender. It is believed the change may be accelerated by environmental conditions. A shortage of males, for example, may induce an earlier sex change.Photo by: Fausto De Nevi Herrera
Service stationsTiger groupers can often be found resting on the bottom with their gills and mouths flared open so smaller fish can clean off parasites. While it appears threatening, it’s a docile act that is mutually beneficial.Photo by: Fausto De Nevi Herrera
Mr. PersonalityDuring spawning, normally sedentary goliaths are known to “dance” or “shimmer” up the water column. They don’t reach sexual maturity until 5-6 years old.Photo by: Fausto De Nevi Herrera
By Rod Griffin
Many large groupers — black, Nassau, yellowmouth, yellowfin and tiger, among others – have been fished out, or nearly so, in much of the Caribbean. In the Gardens, however, they are abundant, including the granddaddy of them all, the goliath grouper.
Goliath groupers live large. Not only are they physically imposing, they have personalities to match. The big lugs are insatiably curious, adorable and incurably romantic.
Today, one goliath followed Kim Richie, a coral microbiologist from the Mote Marine Laboratory, for the entire morning dive.
During the spawning season, July to September, 20-80 of these gentle giants will gather at the same reef, often traveling more than 100 miles to get there. Scientists say the spawning is linked to the lunar cycle.
During the courtship, the males swim in a way that can only be called swaggering. They also change color, becoming darker (and presumably more mysterious). Males jockey for position among the females, 100 to 150 feet undersea, and let out low guttural sounds. These macho goings on, which have been recorded on audio, reach their peak late in the evening.
Photo by: Ian Shive, courtesy of The Nature Conservancy
At a precise moment, usually after midnight when the moon is full, the female surges up toward the surface, followed by one or more males. As the female releases her eggs, the males are by her side, ready to fertilize the eggs. The eggs develop into kite-shaped larvae as they drift in the water column for up to several months before settling into the seabed.
This love fest happens just once a year, so everything has to be just right. Indeed, scientists believe the egg release occurs at night, not because groupers are so romantic, but because darkness limits the number of eggs other fish can find and eat.
As for the goliaths we see in the Gardens, no one knows exactly where they aggregate to spawn. It’s almost certainly outside the park. Cuban scientist Fabian Pina, a leading expert, hopes to find out where. The site, should he succeed in finding it, may lead to the creation of a new marine protected area.
EDF nominated Pina for a three-year Pew Fellowship in Marine Conservation to expand his study of goliath grouper populations in Cuba. In February, he was selected to receive the prestigious grant. It marks the first time a Cuban researcher has received the $150,000 scholarship, akin, in the marine science world, to winning a MacArthur “genius grant.”
Photo by: Boon Hwee
The perils of love
The groupers’ curiosity, sedentary nature and spawning behavior make them easy targets for fishermen. Once favored as a trophy fish, goliaths were fished to near extinction in Florida, before they were protected in 1990. They have since recovered somewhat but are still endangered throughout the Caribbean due to their low birth rates, slowness to reach maturity and the loss of mangrove habitat.
Some fishermen in Florida want to resume fishing, blaming grouper feeding habits for reducing other fish populations. The science, however, doesn’t support their claims. Recent studies show that goliaths mostly eat crabs and other crustaceans.
After diving among these huge, gentle creatures, it would be heartbreaking for them to disappear forever from these waters. But without continued protection, they will.
Cuba: What’s at stake?
3,000 miles of coastline containing mountain rainforests and wetlands teeming with plants and animals—many found nowhere else »