Hawaiian Reef Fauna:
- Cambrian Period
- Ordovician Period
- Silurian Period
- Devonian Period
- Jurassic Period
- Cretaceous Period
- Modern Era
Hawaiian Reef Fauna — The Vertebrates continued
Filefish are closely related to the triggerfish and like them, occur in a variety of patterns and colors. At least 5 species have been identified in Hawaiian waters, one of them, the flamboyant Fintail Filefish (Pervagor spilosoma), is found nowhere else in the world. Filefish, or "leatherjackets" as they are sometimes called, resemble both triggerfish and puffers in appearance. The Scrawled Filefish (Aluterus scriptus) looks very much like a puffer while the Saddled Filefish (Paraluteres prionurus) takes it one step further and actually mimics a puffer species that looks very much like it known as the Saddled Puffer (Canthigaster valentine).
Seven species of parrotfish have been identified and described from the coral reef communities of Hawaii. All are brightly colored, some incredibly so! The Star-Eyed Parrotfish (Catatomus carolinus) is particularly beautiful with its cobalt blue body and radiating scarlet eye markings. Male and female parrotfish are usually quite different in color. Males are usually blue or green, females are reddish-gray.
The hard, parrot-like beak of these amazing fish is capable of grinding down coral reef rock. In their search for algae the parrotfish scrape away at the surface of the reef, chewing up hard coral rock and ingesting it along with the algae. The indigestible coral debris is then excreted. As it turns out, much of the fine coral sand surrounding the coral reefs of Hawaii is produced by parrotfish.
Pufferfish also occur in Hawaiian waters, as do the closely related porcupine fish. Fourteen species of pufferfish and 4 species of porcupine fish have been identified here, some of them quite beautiful and striking in appearance. Known as the "o'opu hue", the pretty little Spotted Pufferfish (Arothron meleagris) feeds on mollusks and crustaceans. Their strong, robust jaws make short work of these hard-shelled creatures. The Porcupinefish (Diodon hystix) is certainly one of the most bizarre forms of life in the ocean, especially when its spine-covered body is fully inflated. Bristling with sharp spines, the Porcupinefish is nearly impervious to any attack by predators.
At least 28 species of wrasses have been identified in the coral reef habitats of Hawaii. Many of these are found nowhere else in the world. This large family of tropical fishes is noted for its extraordinary color patterns which can vary dramatically depending on the age and sex of the fish. Wrasses also vary in their feeding habits. Most feed on small invertebrates like snails, worms, echinoderms, and crustaceans, but a few have become quite specialized in their method of feeding. These are the cleaner wrasses. This group of remarkable wrasses forms "cleaning stations" along the reef. Here, they service a wide variety of fish, feeding on the parasites attached to them, stripping off infected or dead tissue, and cleansing any small injuries or wounds.
The wrasses rival the larger reef fish in their beautiful combinations of colors and patterns. A number of Hawaiian species are particularly flamboyant and showy. The gorgeous Yellow-Tail Coris (Coris gaimard) may be the most impressive, but several other species deserve special mention including the Hawaiian Cleaner Wrasse (Labroides phthirophagus), the dazzling Ornate Wrasse (Halichoeres ornatissimus), the stunning and aptly named Psychedelic Wrasse (Anampses cuvier), and the unique Bird Wrasse (Gomphosus varius) with its elongated "beak-like" mouth.
A host of other fish species occurs in the coral reef habitats of Hawaii including anthias, barracudas, blennies, damselfish, cardinalfish, goatfish, jacks, and flounders. Together they form an extremely rich community that has persisted for millennia but may be under threat today.
The coral reefs of Hawaii and indeed of the whole world are meters or gauges of the general health of the planet because they are extremely sensitive to any change in the conditions necessary for their survival. Minor deviations in seawater temperature, chemistry, and sediment load can be devastating to coral reefs. They are also under continuous attack by reef-eating organisms.
Whereas global increases in seawater temperature may actually increase the range of reef-building corals to slightly higher latitudes, changes in seawater chemistry can be more profound and detrimental. Acidification of the oceans will have an obvious impact on any CaCO3-secreting organism as has been shown in many studies. Also, any change in the delicate balance between pH and oxygen content can result in dense "blooms" of coralline algae which can suffocate coral polyps. The dumping of sewage into protected bays and harbors can produce anoxic, oxygen-poor stagnant waters which are quickly fatal to reef-building coral.
Soil erosion, whether natural or as a result of dredging or construction can likewise have a devastating effect on coral. Except for the healthy reefs around Pu'uki'i Island, the rest of Hana Bay in Maui contains dead or dying coral, all as a result of high sediment load in the water. A shroud of fine silt literally blankets the reefs in the bay.
Reef-eating organisms can also have a significant impact on coral reefs, especially if the reefs are stressed. The Crown-of-Thorns Sea Star heads the list of culprits, but many other creatures feed on coral polyps or the algae that is associated with them. Chitons, parrotfish, and the Cushion Sea Star are good examples. Also, coral reefs are home to numerous infaunal, rock-boring organisms that burrow into the limestone reef rock. Creatures like rock-boring urchins and clams are quite literally agents of erosion, although their impact on coral reefs is small.