Replenishment of crustacean associates of coral isolates in the central region of the Great Barrier Reef

1 Pages·1991·0.36 MB·

by  N P Preston

398 MEMOIRS OF THE QUEENSLAND MUSEUM
REPLENISHMENT OF CRUSTACEAN The results of this study suggest that the amount of space
ASSOCIATES OF CORAL ISOLATES IN THE available is not necessarily a limiting resource for
CENTRAL REGION OF THE GREAT crustaceans that have formed an association with living
BARRIER REEF corals. Nor is it the case for free-living species that inhabit
Mast coral reef habilats support a rich fauna of crustacesn dead corals. Consistently lower yields of agile shrimps and
associates (Bruce, 1976), These associations range from the microcrustaceans from standard sized units of live and dead
use of corals as one of a range of habitats (Coles, 1980) corals at the inner and outer shel reefs compared with the
through to obligate species feeding on coral mucus (Knud- mid-shell reefs indicate that the former sustain relatively
sen, 1967). Although previous ecological studies have re- depatiperatée populations of these crustacean associates. Rela-
vealed local and regional variations in species composition tively low rates of replenishment by recruitment or migration
and abundance of coral dwelling crustaceans (Abele. 1976) apparently maintain this cross-shelf pattern,
there have been few aliempts to quantify distributions, abun- Regional variation in replenishment of live corals by ob+
dances and species replenishment systematically atany scale. ligate species probably reflects the regional population den-
The present study was a four year survey of the crustacean sily of the host corals. In order to establish if a similar link
fauna associated with live and dead Pocillopora verrucosa. exists between the distribution and abundance of free-living
The crustaceans were sampled systematically (rom isolated Species and concurrent patterns of particular habitats we need
corals placed al coral reel9s located on a transect spanning the to know more abou! the connection between these species
width of the continental shelf in the central region of the and their habitars.
Great Barrier Reef. The location of the reels and thesampling
methods used are described in detail in Preston and Doherty Acknowledgements
(1990). This study was funded by an Australian Marine Science
The results of this study demonstrated pronounced cross- and Technologies grant. J am grateful to P.J, Doherty for
shelf patterns in the species composition and abundance of initiating this study and for providing the samples, I thank
crustaceans that colonised cleared corals. These patterns the captain and crew of the 8MV Harry Messel9 and the many
persisted (hroughout the four year study. volunteer divers that assisted in the field work. A.J, Bruce
Among the microcrustaceans copepods were the dominant and P, Davie provided valuable assistance in taxonomy,
taxa found on live and dead corals in the mid-shelafn d outer
shelf reefs. Tanaids and cumaceans were more dominant on Literature cited
the inner shelf reef particularly on back reef sites. The toral Abele, L.G. 1976, Comparative species richness in fluctuat-
abundance of microctustaceans was significantly greater on ing, and constant environments: Coral-associated de-
the mid-shelf than on the inner or outer shelf. capod crustaceans, Science 192; 461-463.
Live and dead corals from the mid-shelf reefs yielded Bruce, A.J. 1972. Shrimps and prawns of coral reefs, with
significantly greater numbers of agile shrimps than those special reference to commencalism. 37-94, In A.O,
located al the innoueterr shoelfr ree ts. On all reefs the shrimp Jones and R, Endean (eds) 8 Biology and geology of coral
fauna on live corals was dominated by a single species; reefs9, Vol. TIT, Biology, 2. (Academic Press: New
Pertclimenes amymone. However, monthly comparisons of York).
community structure and faunal similarity revealed regional Coles, $.L. 1980. Species diversity of decapods. associated
variation in spécies replenishment following disturbance of with living and dead coral Pocillapora meandrina.
live corals. By contrast, the agile shrimp associates of dead Marine Ecology Progress Series 2281-291,
corals showed a more even distribution of individuals among Knudsen, J.W. 1976. Trapezia and Tetralia (Decapoda,
species and a more regular pattern of regional species re- Brachyura, Xanthidae)a so bligate ectoparisites of pocil-
plenishment, loporid and acroparid corals, Pacific Science 21: 51-57.
Destructive sampling at the end of the survey revealed that Preston, N.P_and Doherty, PJ. 1990, Cross-shelf pattems in
live corals on all reefs supported a common group of seden- the community structure of coral dwelling Crustacea in
tary macrofaunal associales. However, there were signifi- the central region of the Great Barrier Reef. 1: Agile
cantly fewer of these associates on the inner shelf reef. On shrimps. Marine Ecology Progress Series 66: 47-61.
dead corals there were similar numbers of sedentary macro-
faunal associates at all locations bul pronounced cross-shelf N,P, Preston, CSIRO Marine Laboratories,
patterns in species composition. Cleveland, Queensland 4163, Australia.