Courtesy of Genette Waddell
In honor of the quickly approaching month of August, today's creature of the week will also be August's Keystone Species: The Goliath Grouper.
Now, the Atlantic Goliath Grouper is a massive fish (in fact the largest grouper in the western Atlantic), able to reach lengths of 8.2 feet and weigh up to 800 pounds.(1) Like many large organisms of the ocean, goliath groupers have longer life spans. The oldest recorded thus far is 37 years, but scientists believe that they most likely could life upwards of 50 years. (2)
The Atlantic variety of the Goliath Grouper can be found in the western Atlantic, from Florida to Brazil, and throughout the Gulf of Mexico, as well as in the eastern Atlantic off the coast of northern Africa. (1) The Pacific variety of the Goliath Grouper can be found off of the coast of southern California down to Peru. (1)
These fish can be found at very shallow depths down to 150 feet. (2) The best place to see a Goliath Grouper is among areas of coral or rock and mud bottoms. (2) Mangroves and estuaries provide the perfect nurseries for the juveniles of the goliath grouper to grow safely. (2)
Goliath Groupers are lone wolves, preferring to set up a territory that they aren't too keen to share with other Goliaths. In fact, Goliaths can produce a drum like sound that travels far through to water to declare their space as off limits to others. (2) If that doesn't deter other Goliaths, an individual will also flare its pectoral fins and open its mouth to show its three to five rows of teeth! (2)
Now what would this fish eat, you may wonder? These fish prefer a nice spiny lobster dinner, as well as other hard shelled invertebrates, octopus, fish, and sometimes a baby sea turtle or two for dessert. (2) Goliath groupers are very patient, as they are sit-and-wait predators, also known as ambush predators. They let the food come to them before gulping it whole.
Most groupers are sequential hermaphrodites (like the parrotfish, remember?). (2) More specifically, groupers follow the pattern of starting as female, and a few larger individuals changing into male when they mature. (2) This is termed protogynous ("first female") hermaphroditism. Though this hasn't been found yet in Goliath Groupers, many scientists believe that there is a high likelihood that Goliaths are protogynous hermaphrodites. (2)
Goliaths actually don't reach sexual maturity until a few years have passed. In fact, males reach maturity at 4-6 years, and females at 6-7 years. (2) Spawning occurs during the later summer months, and is generally dependent on the lunar stages. (2)
Sadly, this amazing fish is now listed as critically endangered. Because of its size, Goliath Groupers have been considered prized sport fish for many years. (1) The species was declared as protected in the U.S. in 1990. (1)
Learn more about the Goliath Grouper at the links below: