19131

Reef 19-131 has been manta tow surveyed 12 times since 1989. After an initial increase in reef-wide live coral cover between 1989 and 1994, remaining at a moderate (10-30%) level through to 1996, there was a subsequent decline to a low level (1-10%) by 1999. This decline was most likely due to the effect of Cyclone Justin, which remained off the Whitsunday coast for an extended period in March 1997. From 1999 a period of recovery ensued up until 2002 when reef-wide live coral cover was at a moderate level. Surveys in 2003 indicate that reef-wide live coral cover on this reef has again declined. In the absence of COTS the most likely cause of the recent decline is the 2002 bleaching event. Reef-wide live coral cover is currently low (1-10%) on this reef and it is classified as No 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 2003.

Detailed surveys reveal a gradual trend of increasing coral cover until 1996 followed by a marked decline to moderate levels in 2000. Cover of hard coral decreased from a six year maximum of 62% in 1996 to 35% in 1997, and has not changed significantly since. The decline in coral cover, is attributed to the effects of Cyclone Justin. Hard corals in the family Acroporidae were most susceptible to this disturbance with large declines recorded in the genus Montipora and tabulate life-forms within the genus Acropora. Prior to cyclone Justin the Acroporiidae were the dominant hard coral on this reef however the Faviidae are now the most abundant family l (13% cover). Cover of these corals has remained stable throughout the survey period. Algae cover showed a similar but opposite pattern to hard coral cover, increasing rapidly between 1996 and 1997 and then remaining stable at 57%. Soft coral cover has been consistently low (approximately 1%).
. There have been substantial decreases in the abundance of a range of large, mobile fish species. Increases in the abundance of the family Acanthuridae reflect an increase since 1999 of Naso unicornis and Naso tuberosus. A number of butterflyfish species (particulalry Chaetodon rainfordii and C. aureofasciatus) have declined markedly since 1999, numbers now being the lowest since surveys began in 1994. A number of Scaridae species increased in abundance to 1998 or 1999 before declining markedly by 2000. A similar trend was evident in the family Siganidae, with all species declining in abundance after 1999 and two species (Siganus vulpinus and S. corallinus) which had been recorded since 1994 being totally absent in 2000 counts. A number of species in the family Labridae and Lutjanus carponotatusin the Lutjanidae had also declined in 2000. Causes of these declines are unclear. Damselfish abundances generally fluctuated erratically and yielded no clear trends.

19131 (No. 19-131) is a middle shelf lagoonal reef with an area of 5.6 sq.km. Last surveyed December 2002.







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