effect(s) does the process have on the donor
coral, and how long does it take the donor to
regrow the severed branch? How many fragments can be removed at the same time from a
donor coral, and how long a rest period should
it undergo thereafter? The last two questions
are undoubtedly of particular interest to commercial coral farms.
D. Brockmann after Lirman et al. (2010)
Diego Lirman and his colleagues at the
Rosenstiel School of Marine & Atmospheric
Science at the University of Miami have devoted themselves to this subject and investigated
the seriously endangered Caribbean Staghorn
Coral (Acropora cervicornis). For at least two
years the scientists have been raising fragments
of this species, collected on the nearby reefs,
at a coral farm in the Biscayne National Park
in Homestead, Florida. The cuttings attained a
length of 12–114 inches ( 30.5–289.5 cm) and
formed the basis for the subsequent analyses.
The results of this study were published in 2010
in the scientific journal Coral Reefs, and because they are also of considerable interest for the reef-aquarium hobby they will be summarized here.
normalized
growth rate
2. 5 cm fragment 3. 5 cm fragment
Survival rate of fragmentS relative
to Size and treatment
In the first experiment, 15 fragments measuring 1 inch
( 2. 5 cm) and 1. 75 inches ( 4. 5 cm) in length were obtained from donor corals and glued to substrate rocks
out of the water. After 20 days only 13 percent of the
smaller fragments were still alive, while the figure was
87 percent for the larger specimens. In a subsequent experiment, fragments of both sizes were glued in place
immediately underwater. In this case, 92 percent of the
shorter and 100 percent of the longer cuttings survived.
larger fragmentS increaSe more
rapidly in length
The scientists next investigated whether the increase in
length was greater in the larger fragments than in the
smaller cuttings. The average annual increase in length
was recorded for this purpose. In the case of the larger
fragments the average growth rate was 3 inches ( 7. 6 cm)
per year and 2. 125 inches ( 5. 4 cm) per year in the smaller specimens.
Surprisingly, however, the growth rate of the smaller
fragments ( 1. 4 cm per year per centimeter of original
length) was, in fact, relatively higher on average than
that of the larger fragments (0.9 cm per year per centimeter of original length).
What effect doeS fragging have on
the donor coral?
The donor corals completely replaced their lost branches
within three or four months. However, this growth took
place in two stages: during the first phase ( 24–39 days
after cuttings were taken) they grew noticeably more
slowly than branches from which no fragments had
