Reef Research: Volume 6 No. 4 December 1996

Udo Engelhardt

Update on the latest
fine-scale survey results

he third year of sampling in the Cooperative Research Centre for Ecologically Sustainable Development of the Great Barrier Reef / Great Barrier Reef Marine Park Authority fine-scale surveys is well and truly under way, with nine mid-shelf reefs having been resurveyed. All of the reefs sampled to date are located between Lizard Island in the north and the Daintree coast in the south. As anticipated following last year's fine-scale surveys, active reef-wide or spot outbreaks of COTS (crown-of-thorns starfish) were found throughout the survey area. Localised COTS densities of between three and ten times sustainable levels (= 30 COTS per hectare) were detected at every single reef surveyed. As expected, the proportion of mature starfish in outbreaking populations has increased significantly since last year. Large, mature COTS have considerably higher food requirements compared to their juvenile stages that have dominated many populations over the last couple of years. Consequently, levels of coral mortality have also increased at certain reefs. At quite a number of individual survey sites, live hard coral cover has now been reduced to between 0% and 10%. COTS numbers at many sites remain unsustainably high with a further reduction in the mean live coral cover highly likely in the near future.

Table 1 illustrates the observed changes in reef classification and status since the transect-based surveys commenced in 1994-95.

Reef ID Reef Name Latitude Status
94-95 Status
95-96 Status
96-97
14-143 North Direction Reef 14°45'S ASO AO AO
14-132b Rocky Islets Reef (b) 14°52'S ASO AO AO
15-019 Long Reef 15°03'S ASO AO AO
15-024 Mackay Reefs 15°08'S ASO AO AO
15-033 Lark Reef (East) 15°17'S NO ASO ASO
15-070 U/N 15°30'S NO ASO ASO
15-084 Irene Reef 15°39'S ASO ASO ASO
15-089 Endeavour Reef (East) 15°46'S ASO ASO ASO
15-095 Evening Reef 15°54'S AO ASO ASO

Reef ID	Reef Name	Latitude	Status 94-95	Status 95-96	Status 96-97
14-143	North Direction Reef	14°45'S	ASO	AO	AO
14-132b	Rocky Islets Reef (b)	14°52'S	ASO	AO	AO
15-019	Long Reef	15°03'S	ASO	AO	AO
15-024	Mackay Reefs	15°08'S	ASO	AO	AO
15-033	Lark Reef (East)	15°17'S	NO	ASO	ASO
15-070	U/N	15°30'S	NO	ASO	ASO
15-084	Irene Reef	15°39'S	ASO	ASO	ASO
15-089	Endeavour Reef (East)	15°46'S	ASO	ASO	ASO
15-095	Evening Reef	15°54'S	AO	ASO	ASO

Table 1.
Summary table of locations and respective status of mid-shelf reefs surveyed for Acanthaster planci using fine-scale survey methodology.

AO = Active Outbreak
ASO = Active Spot Outbreak
NO = No Outbreak
U/N = unnamed reef

Fine-scale surveys will continue early in the new year (1997) with mid-shelf reefs remaining the primary focus. In an effort to detect early signs of a possible geographic spread of the outbreaks to the south, a number of reefs in the Central Section of the Marine Park (south of the Mission Beach area) will be surveyed for the first time. Further updates on the latest developments in the ongoing COTS saga will be provided in the next issue of COTS COMMS. Stay tuned.
Navy involvement in local-scale COTS controls

Well, the Australian Navy is yet again lending a helping hand. A bunch of Navy divers under Lieutenant Pete Mellick based at HMAS Cairns are assisting Cairns-based tour operators in their spare time to locally control active COTS outbreaks. Navy staff have offered their services for free in return for a ride to the Reef. The latest word is that the volunteer divers are really starting to get their eyes in on the elusive starfish and are starting to make a difference in controlling COTS outbreaks. This Navy initiative will surely be welcomed by those currently trying to keep the effects of local outbreaks to a minimum.
COTSWATCH update

The statistics for our Reef-user scheme - 'COTSWATCH' for the period from 13 August 1996 to 6 January 1997 are pretty impressive. Thanks to all those dedicated volunteer observers, the COTS program received some 255 completed survey forms presenting information on 393 individual sites from some 61 different reefs located throughout the Great Barrier Reef Marine Park. However, the focus of both starfish activity and COTSWATCH reporting has remained in the Cairns Section, with most records coming from mid-shelf reefs between Cooktown and Innisfail.

Many thanks to all the new and/or regular COTSWATCHERS out there for continuing to supply valuable information on the latest COTS developments on the Reef.

Valued contributors include:
A Kelly / Great Adventures, Cairns; A J Lloyd / Ingham; A Nichols / Reef Biosearch, Port Douglas; B Knuckey / DoE Gladstone; B Moors / Port Douglas; Staff of Big Cat Green Island Cruises / Cairns; C Cattanach / Trinity Beach; C Coxon / Port Douglas; C Kemp / Sunlover Cruises, Cairns; C Packard / Mareeba; C Purdon / DoE Townsville; C Rowe / Sunlover Cruises, Cairns; C Schoenberg / Townsville; Staff of Coral Princess Cruises / Townsville; D Baird / Reef Biosearch, Port Douglas; D Orgill / DoE Gladstone; D Schapendonk / Great Adventures, Cairns; D Wachenfeld, I Johnston & J Moxham / Undersea Explorer, Port Douglas; D Wiseman / Sunlover Cruises, Cairns; G Bennett / Deep Sea Divers Den, Cairns; G Burns / Bribie Island; G Grant / Sunlover Cruises, Cairns; G Inglis / DoE Dungeness; G Connett / Port Douglas; H Larsen / Cairns; H Jones / United Kingdom; H Malcolm / DoE Pallarenda; I Davis / Great Adventures, Cairns; I Stapleton / Nimrod Cruises, Port Douglas; I Werner / Germany; I Poelger / Holloways Beach; J C Rowe / Clovelly; J Hallback / Sweden; J Holcombe / Kandos; J Meyer / Big Cat Green Island Cruises, Cairns; J Money / Sunlover Cruises, Cairns; J Purcell, J Sando, S Wilson, R Schnauer, R Shutte, R Aiello, T Forsyth, M McCarthy, T Lace, M Woodhouse, P Paxton & J Wells / Great Adventures, Cairns; J Weisgerber / Cairns; J Wildforster / Reef Biosearch, Port Douglas; K Robertson / England; L Knowles / Mossman; L Squire / Cairns; M Burnham & M Ford / DoE Lucinda; M Greet / Port Douglas Dive Centre, Port Douglas; M Walker / United Kingdom; Staff of MV Poseidon / Port Douglas; N Griffiths / Sunlover Cruises, Cairns; N Sorensen / Cairns; P Heatherwick / Port Douglas; P Mellick / HMAS Cairns; P Woolley / Cammeray; R Buck / DoE Mackay; R McElligott / Reef Biosearch, Port Douglas; R Persson / Sweden; R Phelan / Wahroonga; R Townsend / Great Diving Adventures, Cairns; R Fisher / Rosslyn Bay; R Op Den Brouw / Cairns; S Balson / Cardwell; S Brown / United Kingdom; S Coulthard / United Kingdom; S Fisher / Mackay; S Moon / Ocean Spirit Cruises, Cairns; S Richards / Captain Cook Cruises, Cairns; S Goodhew / Aquatic Images, Cairns; T Anger / Cranbrook; T Arakawa / Cairns Dive Centre; T Ayukai / Townsville; V Nelson / Townsville; W Mahon / Sunlover Cruises, Cairns.

Late addition to Panama symposium
Below you'll find a late addition to our list of abstracts of COTS-related papers presented at the recent International Coral Reef Symposium in Panama City (see COTS COMMS, Reef Research, September 1996). A paper by Drs Roger Bradbury and Robert Seymour came in as a late entry and thus missed the cut for the previous issue of this newsletter. Anyway, for completeness sake here it is.

Waiting for COTS

R. Bradbury¹ and R. Seymour²
¹National Resource Information Centre Canberra ACT 2600
²University College London, England WC1E 6BT

uring the past few years, a significant number of practising scientists have reached broad consensus on the `cause' of outbreaks of the crown-of-thorns starfish on the Great Barrier Reef. They see the observed series of outbreaks as a novel, system-wide episode of anthropogenic origin. As a result, scientific interest in the outbreaks is shifting from causes to consequences. In particular, our interest is in the consequences of repeated outbreaks on the ecosystem of the Great Barrier Reef. In this paper, we argue that our analysis of the available evidence shows two distinct trends: the outbreak dynamics seem to be changing from a travelling wave to a system-wide pulse; and the proportion of reefs available to host the outbreaks is declining through time. The first trend may signal a qualitative shift in the dynamics, while the second may be the first indication of a long-term degradation of the ecosystem. We await the data on the progress of the current outbreak episode to help clarify these trends.

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