Almost all divers will tell you that the large, colorful, male parrotfish are the most beautiful fish in Hawaiian waters, but the female parrotfish are quite drab-looking and not very colorful.
Most people don’t know that the large, colorful, male parrotfish started out its life as a female. Many fish species are all hatched as females, and then for the purpose of reproduction one of the largest females will convert into a male!
The Hawaiian name for the parrotfish is “uhu,” which means “loose bowels.” These parrotfish feed on old and dying corals along with algae they bite off the reef with their large, fused teeth. The parrotfish are often seen pooping out sand that makes our beautiful beaches.
Trying to identify different species of parrotfish can be very difficult because most of the parrotfish species start out as gray-colored babies. At about a year old, the babies turn into juveniles and develop the reddish-brown colors.
I was scuba diving in Kaua‘i over and over at the same spot on the reef studying coral diseases, and I often saw a small school of eight, mid-sized female parrotfish. There were no large, bright, blue-green males in the school. Over a period of about a year, one of the large females started changing colors.
The reddish colors started to turn into a bright blue color, which gave the fish a very unusual pattern for about six months. Within a year, the large female turns into a bright blue-green male and starts breeding with the females. The large colorful male breeders are called supermales.
Until we had the ability to use DNA sequencing, we did not know for sure that the female had converted into a male. The Hawaiians in the past gave a different name to the females than they gave to the males. The female is called “uhu palukaluka,” and the large, brightly colored supermale is “uhu ‘ele‘ele.”
One large supermale can breed with five to 10 females and produce millions of baby parrotfish. This is important because these fish keep the coral reef healthy by eating dying coral, which makes room for new corals to grow. And the parrotfish converts the old coral into sand, which makes our beaches.
When people spearfish, they often will take the large male because it is so beautiful and will make a good picture.
But this is really damaging to the reef system. It takes about a year for a large female to convert into a male, so if the male is removed there will be no reproduction of the entire colony of females for several years. On the other hand, if a diver takes a female then only one reproductive cycle will be missed.
You can see both the female and male uhu in action on my webpage at www.underwater2web.com. In the picture at left, the female, ember parrotfish converted to a supermale.
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Terry Lilley is a marine biologist living in Hanalei. He is co-founder of Reef Guardians Hawai‘i, a nonprofit on a mission to provide education and resources to protect the coral reef. To donate to Reef Guardians Hawai‘i, go to www.reefguardianshawaii.org.
