Uhu--Parrotfish--the Beach Makers

It is nice to see the Parrotfish again. The last time was in the Florida Keys. What beautiful and colorful fish the male is!

Parrotfishes are a group of fishes that are found in relatively shallow tropical and subtropical oceans throughout the world. The approximately 90 species are found in coral reefs, rocky coasts and seagrass beds, and play a significant role in bioerosion.

Parrotfish are named for their dentition. Their numerous teeth are arranged in a tightly packed mosaic on the external surface of the jaw bones, forming a parrot-like beak with which they rasp algae from coral and other rocky substrates (which contributes to the process of bioerosion).

Although they are considered to be herbivores, parrotfish eat a wide variety of reef organisms, and it is important to note that they are not necessarily vegetarian. Their feeding activity is important for the production and distribution of coral sands in the reef biome and can prevent algae from choking coral. The teeth grow continuously, replacing material worn away by feeding. Thepharyngeal teeth grind up coral rock that the fish ingests during feeding. After they digest they excrete the rock as sand helping to create small islands and the sandy beaches of the Caribbean. One parrotfish can produce 90 kg of sand each year.

The development of parrotfish is complex and accompanied by a series of changes in color termed polychromatism. Almost all species are sequential hermaphrodites, starting as females (known as the initial phase) and then changing to males (the terminal phase). The marbled parrotfish (Leptoscarus vaigiensis) is the only species of parrotfish known not to change sex.

In most species, the initial phase is dull red, brown or grey, while the terminal phase is vividly green or blue with bright pink or yellow patches. The remarkably different terminal and initial phases were first described as separate species in several cases, but there are also some species where the phases are similar.

In most parrotfish species, juveniles have a different color pattern than adults. Juveniles of some tropical species can alter their color temporarily to mimic other species.

Feeding parrotfish of most tropical species form large schools grouped by size. Fights of several females presided over by a single male are the norm in most species, the males vigorously defending their position from any challenge.

Parrotfish are pelagic spawners; that is, they release many tiny buoyant eggs into the water which become part of the plankton. The eggs float freely, settling into the coral until hatching.

Seven kinds of parrot fish can be found in Hawaii:

• Stareye parrotfish (ponuhunuhu) have bright blue faces and fins with a brown body. They also have pink stripes surrounding their eyes in a starburst pattern. Their eyes have a bulging appearance.
• Yellowbar parrotfish are primarily blue with a bright yellow or white stripe just behind each pectoral fin. The males show yellow stripes and the females show white stripes. They also have pinkish-red markings on their bottom jaw.
• Spectacled parrotfish have a blunt head and a broadly rounded body. Females (uhu ‘ahu ‘ula) are purplish brown with a red rail. The males (uhu uliuli) are blue with a purple overlay in the scale margins. There is also a yellow mark on the pectoral fin bases. Both genders have saddle-like bars just ahead of their eyes.
• Bullethead parrotfish (uhu) (in picture) are the most common of the large parrotfish. The males have yellow and orange centers with surrounding blue markings. Females are reddish brown with a series of white spots toward their rear and red markings around the mouth.
• Regal parrotfish (lauia) are seen less frequently. The females are pale to red with light stripes on the belly. The males are salmon pink to orange with turquoise markings.
• Palenose parrotfish (uhu) males are mostly blue, yellow and pink. The females are mottled gray or olive brown. This variety is normally less than 10 inches long.
• Redlip parrotfish (uhu palukaluka) have blunt angular heads. The males are green, turquoise or purple with a two-color scheme body. The females are purple and brown with dark scale markings.