BAHAMAS REEF FISH (6) PARROTFISH: COLOURFUL CORAL CHARACTERS
The term ‘PARROTFISH’ comprises many related species (80) around the world inhabiting shallow tropical and subtropical waters. They are commonly found in coral reefs and seagrass beds, and along rocky coasts. They play a significant role in BIOEROSION. Here are some examples of 5 of this species that inhabit the waters of the Northern Bahamas
PARROTFISH FACTS TO ASTOUND AND IMPRESS YOUR FRIENDS WITH
A. FEEDING HABITS
1. Named for their dental arrangements – a mouthful of teeth, forming the characteristic ‘beak’
2. Primarily herbivore but not above snacking on small creatures / organisms or even molluscs
3. Their teeth grow continuously, replacing ones worn away by feeding on coral
4. As they feed on algae etc, their teeth grind up the coral, which they ingest
5. Then (get this!) they digest it and excrete it as sand… it’s a component of your favourite beach!
6. “One parrotfish can produce 90 kilograms (200 lb) of sand each year”. Wiki says so – it must be true
7. They are a vital species in preventing algae from choking coral
B. PERSONAL INFORMATION (theirs, I mean)
1. Some species secrete a protective mucous cocoon to sleep in or to conceal themselves from predators
2. A mucous substance also helps heal damage, repel parasites, & protect them from UV light
3. As they develop, most species change colour significantly to become vivid adults – “polychromatism”
4. Some juveniles can change colour temporarily to mimic other species as a protection
5. Most are “sequential hermaphrodites”, turning from female to male (a few change vice versa)
6. They tend to hang out in groups of similarly-sized / -developed fish
7. Single males tend to have several lady friends, and aggressively defend their love rights
8. Parrotfish are PELAGIC SPAWNERS. Females release many tiny buoyant eggs into the water, which float freely and settle into the coral until they hatch
9. Unlike other fishes, they use their pectoral fins to propel themselves
10. Their feeding behaviour makes them unsuitable for marine aquariums
Anyone interested in getting more information about Parrotfishes – maybe about that whole female / male transformation thing? – is recommended to look at an article by Tim Smith of Miami University, Ohio entitled THE BAHAMAS: A CLOSER LOOK AT THE COLORFUL AND UNIQUE PARROTFISH Click on the P-word to get to it directly.
If you are pressed for time, here is the article conveniently digested into bullet points:
- a superior competitor among herbivorous reef fishes
- large, heavy scales in regular rows on head and body, with teeth fused together to form a beak-like jaw
- unique pharyngeal dentition: upper interlocking pharyngeal bones located above the gills rest plush against the lower pharyngeal bone to form the pharyngeal mill (molar-like teeth in their throats) used to grind up the hard coral skeleton that contains microscopic algae
- the crushed calcareous material travels through the fish’s digestive system and is voided on the reef as white coral sand
- some fish will return to the same location to deposit this calcareous powder resulting in the formation of small hills over time
- most parrotfish live on reefs from which they rarely wander far
- rainbow parrotfish are thought to use the sun for navigation to travel from its nocturnal cave in deeper water to the shore to feed
- all parrotfish uniquely use the pectoral fins located behind the gills for propulsion (not their caudal or tail fins)
- in addition to scraping algae from substrate, some parrotfish browse on sea grasses
- at night, each fish separates to search for a suitable place within the reef to sleep.
- the large, thick scales of the parrotfish are strong enough to stop a spear in some species
- the flesh is soft and spoils quickly, the parrotfish is not known as a food fish in the Bahamas
- in Hawaii they are eaten raw and at one time were reserved for royalty
- the blue parrotfish may carry ciguatera-producing toxins that result in illness when consumed
- it’s high time for another picture or two
Some more bullet points from Tim Smith’s article:
- at night some species simply burrow into the sand
- others secrete a filmy mucus cocoon in 30 minutes which masks its scent, affording the parrotfish protection from coral reef night predators such as sharks and moray eels.
- the parrotfish has the ability to undergo sex reversal in which female fish become males
- parrotfish born male remain male throughout their lives and are called primary males.
- female born fish may change sex & color to become male – secondary males or referred to as supermales or terminal males.
- some parrotfish are chameleon-like, changing their colors to match their surroundings.
- parrotfish spawn throughout the year
- there are 80 species of parrotfish
- the vibrantly colored parrotfish plays a major role in maintaining the cycle of reef growth and erosion
- “Do not be alarmed if you experience a sudden drift of sediment or hear the crunching sound of coral the next time you are snorkeling or diving along a coral reef in the Bahamas. It is just a parrotfish doing its job.”
- I sense a stoplight is about to interrupt the proceedings… and here it is
STOPLIGHT PARROTFISH (adult and, below, juvenile form)Thanks to Melinda of Grand Bahama Scuba for her fantastic illustrative pics; the header is mine own
It’s possible that I won’t be quite as attentive with posts / replies to comments etc over the next couple of weeks or so. I’ve a few things in the pipeline, but it may depend on wifi access… I’m giving up trying to use an iPhone to post while on the move – fine for snaps, but not for anything more complicated. So apologies in advance, and like Arnie, I’m afraid I’ll be back…