ABOUT MARINE LIFE- Reef Fish

25% of all reef fish in Hawai'i are endemic to this archipelago, meaning that they are found nowhere else in the world. This is due to the isolated nature of the Hawaiian Islands. Fish have a pelagic larval lifestage of 9 to over 100 days which may not be enough to reach Hawai'i on the ocean currents. It is believed that most fish species found in Hawai'i have been carried northeastwards from Japan in the Northern Equatorial current and have since evolved into new species.










Hawai'i has two types of fishes: the cartillagenous sharks and rays and the bony fishes. Sharks’ skeleton is made up of cartilage instead of bone. Sharks have 5-7 gill openings on each side of their head whereas bony fish have a single one. Bony fish have a swim bladder and sharks do not- instead they have a large liver containing oil which they use to regulate buoyancy. Sharks have rows of teeth and bony fish have teeth in sockets inside their mouths. There are about 40 species of sharks and about 530 species of bony fishes in Hawaiian waters.

There is a scientific name, common name and Hawaiian name for all fish in Hawai'i. The Reef Triggerfish (Rhinecanthus rectangulus) has a Hawaiian name of Humuhumu nukunuku apua’a which means " (pieced together) triggerfish with a snout like a pig". The Longnosed Butterflyfish (Forcipiger longirostris) has a Hawaiian name of Lauwiliwilinukunuku'oi'oi or “the long-nosed fish which flitters around like a WiliWili leaf” referring to the leaf of a native tree.

 

 

 

 

 

Reef fish are brightly colored and all coral reef fish see in color vision. This is essential for predator-prey relationships. For example the Hawkfish has camouflaged itself to look like coral- this serves both to protect it and give it the advantage when ambushing prey. The Cleaner Wrasse provides a necessary service to other fish and so advertize themselves with a bright yellow strip. Some fish have nocturnal adaptations such as a red coloration which makes them practically invisible at night. Fish coloration also helps with sexual identity whereby different sexes of similarly shaped fish stand out.



Reef fish can change sex, most commonly from female to male.
In species such as the Bird Wrasse when the dominant male in a harem of females is removed, the alpha female will start acting like a male. She will start changing her size and color over a few days and her gonads will start producing sperm instead of eggs. Most fish release their gametes in the water during mating rituals (broadcast spawn), or bottom spawn near a nest, resulting in territorial and protective behaviour.

 

There are cleaning stations on reefs. The Hawai'ian Cleaner Wrasse sets up its own cleaning station with its harem of females on a distinct patch of reef. At these stations other fish stop motionless while the ‘attendants’ clean parasites, dead tissue, and some live tissue. Some studies have shown that the fish visiting cleaner stations have no real need to be cleaned but possibly enjoy the sensation of being ’tickled’ by the cleaners.





Hawaiian reef fish play a vital role to the health of the reef system. Many reef fishes are herbivorous, meaning they feed on algae. If the algae is not kept in check by fish grazing it will compete with coral and may dominate reef systems. This is even more reasons to protect our reef fish from human impacts so as not to further threaten our valuable reef systems. The same fish eat algae off a turtles back, helping it to stay hydrodynamic.


There are cleaning stations on reefs. The Hawaiian Cleaner Wrasse sets up its own cleaning station with its harem of females on a distinct patch of reef. At these stations other fish stop motionless while the ‘attendants’ clean parasites, dead tissue, and some live tissue. Some studies have shown that the fish visiting cleaner stations have no real need to be cleaned but possibly enjoy the sensation of being ’tickled’ by the cleaners.















See Guidelines for how to minimize your impact on reef fish in Puako.

Photographs: Robert Shallenberger, Zach Caldwell, Samantha Birch and Andrew Walsh.

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