Researchers' Diaries

Zoe Richards

Marine and Tropical Biology, James Cook University

Zoe Richards, Marine and Tropical Biology, James Cook University, Qld

Kimberley Coastal Corals – Adele/Montgomery 2009.

Corals living in Kimberley reef habitats are exposed to extreme climatic conditions, so examining these hardy coral communities is of profound interest to wider coral reef conservation biology. In the Kimberley 2009 coral reef survey I documented the assemblage of hermatypic corals living in intertidal reef habitat at Montgomery Reef and in subtidal reef habitats at Adele Island.  Data will be analysed in conjunction with comparative data from other coastal and offshore Kimberley reefs with the intention of highlighting the regional and global importance of this coral reef habitat.

NB: Hermatypic corals are reef forming corals that contain zooxanthellae (unicellular dinoglagellates) in their tissue.

A total of 26 stations were surveyed for corals in the present study (13 Adele/13 Montgomery).  At each station, mean species richness (+SE) was calculated from 4 replicated 15m x 1m coral biopersity belt transects.  Total station richness was calculated from pooled transect data and an additional 20 minute rapid visual search over the station (covering approximately 1000m2).  Overall, 171 reference skeletal samples and matching genetic samples were collected pertaining to 106 species of shallow-water hermatypic coral.

Interestingly, 26 species recorded from Adele Island were not recorded at Montgomery Reef or in other regional surveys.  A particularly unusual feature of the Adele Island coral community is the presence of coralliths (free-living corals) in the high-energy back reef zone on the western side of the island. Coralilths of Psammocora profundacella, Pavona venosa, Cyphastrea chalcidicum and Milleporina sp. occurred amongst rhodoliths (coralline algae balls).  The regional significance of this corallith habitat is yet to be established. 

A total of 113 species were recorded at Montgomery Reef.  Prior to this survey, a total of only 54 species were known to occur.  Coral persity peaked on the mid-littoral fore-reef ramp with 54 species being recorded there. Four species recorded at Montgomery Reef have so far not been recorded at Adele Island or other locations in the Kimberley or offshore bioregions.  While the overall persity of Montgomery Reef is relatively low, it is important to remember these data refer to intertidal species only and in the context of intertidal communities – Montgomery Reef has a substantial and perse coral community.

Research into the corals collected on the Kimberley 2009 Adele/Montgomery expedition continues. However, so far it appears at least four of the species records are new for Australia and an additional three species have been recorded from Western Australia for the first time. A possible new species of coral has also been recorded from both Adele Island and Montgomery Reef, but further work needs to be done to establish it as a new species.

One distinctive feature of the Kimberley coral community is that at the inpidual level, corals are exceedingly healthy and this is likely to be a reflection of the lack of human influence and pollution in the Kimberley region. This project offers the exciting and unique opportunity to gain further insight into coral biopersity, coral community structure and coral species abundance distributions in non-polluted habitats.

(Photo by Zoe Richards)
© Western Australian Museum. (Photo by Clay Bryce)
Goniastrea retiformis, a particularly hardy intertidal coral, utilizes mucus to protect tissue from exposure during low tide at Montgomery Reef.
(Photo by Zoe Richards)
© Western Australian Museum. (Photo by Clay Bryce)
Exposure causes tentacles to contract on the upper surface of this Euphyllia glabrescens colony, pictured at Montgomery Reef.