Parrotfish and coral

[DA Aquamaster]

Parrot fish help remove algae that would other wise hinder the growth of new coral, and free up valuable real estate for new coral in part by chewing up realtively abundant and fast growing corals which creates more opprtunity for slower growing corals to become established. Balance is obviously the key here as too many Parot fish would be a problem.

The Sea Star (crown of thorns star fish) population explosion is a good example of what happens when the population balance is distrubed. a small number of sea stars on a reef is a god thing as it keeps the coral healthy and diverse by providing opportunities for new growth in limited space. But too many sea stars quickly outstrip the coral's ability to recover and entire reefs end up dead, algae covered and ultimately collapse.

 

[Dan Gibson]

I'd called that impressive

which is still about 3/8 of the parrotfishes total volume every day.

 

[archman]

Hmm... I just wrote a teaching outline on Caribbean parrotfish a few weeks ago. Wonder what I remember...

1. Parrotfish "poo" is exceptionally clean carbonate sand, derived from chomping on calcareous/coralline algae, and coral.
2. Far more carbonate reef sand is created from the degradation of the Halimeda-type macroalgaes than from parrotfish. But the parrotfish do it right in front of divers, so it's more cool.

3. Stoplight parrotfish (Sparisoma viride) have this annoying habit of biting down on live corals, and taking big chunks out of them. It seems to be some sort of way the parrotfish "mark territory".

4. Caribbean parrotfish are separated into two genera, Scarus and Sparisoma. Both genera display different feeding types, one type makes frequent, shallow scrapes along dead coral and rocks to eat yummy algae, while the other (Sparisoma I think) prefers making infrequent but much deeper bites. Neither of them show a marked preference for eating live coral.

5. The midnight parrot is the only Caribbean species that doesn't have different-coloured life history phases. They always look look like that.

**off the record, I don't think parrotfish eat the network algae Microdictyon. It covers many Bahamian reefs now, and all the parrotfish I've observed seem to shy away from the junk. There must be a toxin in the stuff. Anyway, the Microdictyon explosion might be driving all the parrotfishes out, as it coats all the rocks and coral, and they don't have many dietary options. Hmmm... this may be a good project for my class this summer. Where's my bloody notebook...

 

[badassbill]

I don't know how much Parrot's "Poo"....but whiile snorkeling in the Caymans last year I had the crap scared out of me by one. As fish stories go, this thing keeps getting bigger each time I think about it...but I would say this Parrot was about 4 feet long and as wide as a basketball. After my initial fear of seeing a fish that big while snorkling, I followed him around for about 10 minutes and he munched the whole time. That fish really "moved" some coral.