When they're sitting on a live, healthy coral head
, if a predator comes by, they just retire into shelter,' she says.
We found that water collected from coral heads
in the field had metamorphosis-inducing strength similar to 30% solutions of laboratory-prepared PW.
Data analysis compared the relative abundance and diversity of species on varying size coral heads
The sensitivity of corals to increases in C was demonstrated by Mitchell and Chet (1975) with coral heads
exposed to low concentrations of various substances, including crude oil (100 ppm) and organic matter (1000 ppm, in the form of dextrose), under controlled laboratory conditions.
Synalpheus charon lives in crevices at the bases of coral heads
(Castro 1971), but its relationship with the coral and other inhabitants of the colony or its predators is unknown.
Many trawls, called roller trawls or rockhoppers, have large rubber discs or steel bobbins that ride over boulders and coral heads
, which might otherwise snag the net.
And three spot damselfish have shifted from branching coral to more sensitive coral heads
as disease has wiped out much of the elkhorn and stag- horn coral formations.
Adults shelter opportunistically in reef crevices (three-spot dascyllus) or in live coral heads
(yellow-tail and humbug dascyllus) (Allen 1991).
The colorful bluish-green or yellowish-orange fish are best harvested in the summer by trapping or gillnetting along sheltered lagoons or among low-waterline coral heads
But fragile reefs are suffering damage from many sources including the anchors of dive and snorkel boats at popular sites (such as Molokini Crater, off Maui)--as well as from divers and snorkelers who unwittingly step on coral heads
, or break them off as souvenirs.
On Wake, an additional task was the blasting of coral heads
in the lagoon so the Clippers could land safely and taxi to the landing and boarding platforms.
There are many shallow coral heads
where these worms hatch, typically around the full moon in May.