TURNER CAY

Manta tow surveys have been conducted on this reef annually since 1994. Over this time, reef-wide live coral cover exhibited a gradual increase to high levels (30-50%) peaking in 1999. Reef-wide live coral cover remained at this level until 2001 when COTS activity increase dramatically and the reef was reclassified as an Active Outbreak. Since this time COTS have been at outbreak levels on this reef and as a result there has been a corresponding decline in reef-wide live coral cover which is currently low (1-10%). Turner Cay is currently classified as Active Outbreak. No bleaching and only low levels of White Syndrome Disease, restricted to a few individual colonies, was recorded from this reef during manta tow surveys in 2002.

Detailed benthic surveys show that the benthic community on the north-east flank of this reef is dominated by soft corals in the family Xeniidae. Cover of soft corals has declined from 37% in 1992 to 28% in the year 2000. The reasons for this decrease remain unclear. Cover of hard corals (particularly the family Acroporidae) increased from 27% in 1994 to stablise at high levels in 1999. In the year 2000 cover of hard corals averaged 33%. Significant increases in the family Scaridae are a little misleading as this rise is due largely to the presence of one large mixed aggregation of Chlorurus sordidus, <>Scarus globiceps and S.psittacus on one of the sites in 1999, though C. sordidus abundance was also elevated in the 2000 survey. The increase in Chaetodontidae is due largely to two species. Chaetodon melanotus numbers approximately doubled to the 1998-2000 levels from a previously stable assemblage, while Chaetodon trifascialis has steadily increased in number since 1996. Declines in the damselfish genera Neopomacentrus and Pomacentrus are due to general declines in several species (N. azysron, P. lepidogenys, P. wardi and P. bankanensis) although both P. lepidogenys and P. bankanensis show a marked recovery in the 2000 survey. Increases in abundance of Plectroglyphidodon (P. lacrymatus) and Chrysiptera (C. rollandi) reflect an increase in the 1999 and 2000 surveys respectively, following prior declines.

Turner Cay (No. 21-562) is an outer shelf lagoonal reef with an area of 5 sq.km. Last surveyed September 2002.







For information on how to read this page, see our explanation .

web@aims.gov.au

Copyright ©1996-1998 Australian Institute of Marine Science

URL http://www.aims.gov.au