It is a protogynous hermaphrodite, meaning it begins life as a female and changes to a male as it matures. It is treatable in humans, but the concern is that ciguatoxin can move up the food chain via bio amplification and spread to other species.
Scientific classification Kingdom: Animalia Phylum: Chordata Class: Actinopterygii Order: Performed Family: Serranidae Subfamily: Epinephrine Genus: Cephalopods Species: Binomial name Cephalopods Argus Synonyms Epimetheus Argus (Schneider, 1801) Bodies Gustavus Bloch, 1790 Serra nus Gustavus (Bloch, 1790) Bodies jacobevertsen Labeled, 1802 Serra nus master Valentines, 1828 Serra nus immune Montgolfier, 1857 Serra nus thirties Saville-Kent, 1893 They come from the Indo-Pacific which is variously a commercial game fish, an invasive species, and occasionally an aquarium resident.
Its species name comes from its resemblance to the “a hundred staring eyes” of the monster Argus in Greek mythology. Larger specimens sometimes develop four to six lighter vertical bars on the back half of its body.
Cephalopods Argus, Vilamendhoo Maldives The species is extremely widely distributed, occurring in warm waters from the Red Sea to South Africa and east to French Polynesia and the Pitcairn group. It makes use of a variety of habitats but prefers the exposed fronts of reefs, at depths of up to 40 m.
Hunting, they lie on the bottom and surge forward, preferring juvenile surgeon fish and crustaceans. This grouper may follow and cooperate with another predator species, such as an octopus or eel or camouflage themselves in a school of surgeon fish.
Multiple individuals may cooperate to harass an eel to get it to flush prey for them. The species typically sit on a coral head, retreating when startled.
Red Sea males defend harems of 2–6 females in territories ranging up to .5 acres (0.20 ha). The male visits each female daily, raising his dorsal fin to signal his approach.
The females emerge from hiding, erecting her own dorsal fin and changing to a lighter color. Territorial disputes may involve “color fights” in which two males positioning themselves at right angles to each other.
They then darken their color and repeatedly switch their bars from dark to light. During courtship, both sexes darken except for a white keyhole-shaped patch at the center of the body.
Known in Hawaii as ROI, the state introduced the species in the 1950s to enhance local fisheries. Hawaii's Division of Aquatic Resources (DAR) finds that ROI have become the reefs' dominant predator.
Their biomass is now greater than that of all other reef fish predators combined. Prized as delicious eating in other Pacific regions, in Hawaii's waters ROI may contain the ciguatera toxin, which builds up in humans and causes serious illness.
A study published in 2007 found that 18% of ROI sampled from Oahu and Hawaii islands had toxins above levels safe for consumption. Due to high variability of toxin levels between individuals in the same area, toxicity cannot be predicted based on location.
Because of the toxicity issues, ROI does not have a functional fishery, with just an average of $1000 per year in sales. Roi's feed primarily on juvenile fish that have recruited the reef.
The family of fish that make up the majority of their diet Scarsdale or Parrot fish, are crucial to the coral reef ecosystem by removing algal growth on coral colonies through feeding. Hawaii has the highest rate of endemic of its nearshore marine fish species at 24.3%.
The lack of natural predators to control ROI populations along with their high efficiency is a major threat to the unique fish fauna found in Hawaii. On Maui, spearfishes participate in “ROI Roundup” tournaments that target these problematic fish, attempting to reduce their numbers and impact.
This practice has spread to other islands, where there are similar tournaments that target ROI and other invasive fish species. These events not only reduce the ROI population, but also work to boost public awareness about this issue.
Groupers are solitary carnivores that hunt near the bottom usually at dusk. Juvenile fish become adults and some change shape or their color.
Click the image(s) to explore further or hover over to get a better view! ROI or peacock grouper, were introduced into Hawaii in 1956 from Mo'area to add to the food source for Hawaiian fishermen.
ROI spend most of their time in deep caves and cracks in the reef where they prey on other fish like allowed, Memphis and Ala'hi. I also make movies for schools, government agencies and the public about our marine life and invasive species like ROI, ta'ape and to'Au.
I have observed several large ROI that seem to stay near the same caves, but they will move when the surf changes or you scare them away. In Canada Bay from the shore out to one mile I have done over 100 kayak scuba dives and I have speared over 80 ROI of which I sent to UH for testing.
This concentration of ROI vs native fish is very dangerous for the long term health of our reefs. Ten years ago at many spots on the north shore like Tunnels Reef, I have seen many of the native fish decline and the ROI spread.
Fishermen do not normally eat the ROI because they have been known to carry the ciguatera toxin, and they could make you very sick! The current test kit for ciguatera is not extremely accurate and cost a lot.
If UH could make a good test kit that cost little then fishermen could go back to catching and eating ROI. Free divers can target certain species without damaging the reef or marine life.
Some scientist claim that ROI take the place of Ulna as a top predator. If we spent more time and money studying Ulna, UK, Mile and other predators and develop additional plans to increase their populations, then we would be returning our reefs to a healthy state.
Using an invasive species to repair a damaged ecosystem rarely if every work! Roi could also carry bacteria that are not native to Hawaiian waters. I did an underwater movie about Kauai's free divers, and they are very good at what they do, and they understand the ocean and marine life quite well.
Rising sea levels, run off, improper building, polluted rivers and over use of certain reefs by tourist cause much more damage to our coastal ecosystem than fishermen do. As scientist, we need to work with fishermen, divers, surfers, hunters and other native people as they are “the eyes on the reef” we need to learn from and share with.
We do not have time to fight over regulations as the sea is changing quickly, and we all need to join together and share our knowledge and efforts. Groupers & Antics, Family SerranidaeGroupers are carnivorous fishes that are typically large and slow moving, found under ledges and caverns.
They feed primarily upon fishes and large crustaceans. Due to the high fish diet, many reef species contain enough ciguatoxin to cause illness and caution should be exercised.
Large groupers are poorly represented in Hawaii'i, with one deepwater endemic, one waif, and one invasive alien species. Small, colorful bassets and antics are better represented but uncommon, preferring deep water or dark caverns.
They feed upon zooplankton and are sexually biomorphic, with harems of smaller, less-colorful females in the company of a male. Soap fishes (Subfamily Grammistinae) produce soapy bitter mucus to deter predators and are rarely seen during the day.