Searching for juvenile COTS

The particular focus of the congress was on the future development and resource use of Pacific island nations in the 21st century. As part of the proceedings, I was able to present a paper entitled 'The early detection of outbreaks of the crown-of-thorns starfish (Acanthaster planci) - implications for local-scale control measures' (see abstract below).

The paper stimulated considerable interest and discussion amongst participants from a large number of Pacific nations currently experiencing starfish outbreaks of a similar nature to the ones affecting the central parts of the Great Barrier Reef. Having had the opportunity to present the paper at two separate sessions - a special coral reef symposium as well as a marine biodiversity session, I feel confident that my presentation would have reached the greater majority of marine scientists and managers present at the congress. Since that time, I've had a number of requests for further information on the new COTS monitoring (fine-scale survey) and control (sodium bisulphate injection) techniques.

In discussions with the coordinator of 'Reef Check 97', a special international initiative as part of the International Year of the Reef (IYOR), it was agreed to incorporate various aspects of COTS monitoring into the program's formal activities throughout the Indo-Pacific region. Furthermore, several individuals as well as overseas tourism operations have indicated their willingness to participate in an expanded Reef-user survey program termed 'COTSWATCH - International'. Following the recent publication of a short promotional article in a regional dive magazine, I anticipate growing interest in this expanded Reef-user monitoring scheme.

Fine-scale surveys of COTS

Only one other paper dealt with aspects of COTS research. Quinn and Kojis reported on a survey of the Northern Mariana Islands where COTS outbreaks have occurred in the past. When applying our criteria for what constitutes an unsustainably high (outbreaking) population of COTS, then at least one of the reefs surveyed in that part of the world appears to be supporting a current active spot outbreak. See their abstract for further details.

Overall, the opportunities for networking and information dissemination as well as information gathering facilitated through the congress were found to be invaluable in gaining an improved appreciation of the truly large-scale nature of the COTS phenomenon.

ABSTRACTS

The early detection of outbreaks of the crown-of-thorns starfish
(Acanthaster planci) - implications for local-scale control measures

---

U. Engelhardt
Great Barrier Reef Marine Park Authority, PO Box 1379,
Townsville Qld 4810, Australia

sing a new transect-based survey methodology, current outbreaks of crown-of-thorns starfish (Acanthaster planci) in parts of the Great Barrier Reef have been detected much earlier than has previously been possible using other survey methods. Intensive, fine-scale surveys have been successfully applied to detecting the early stages of developing A. planci populations including the usually cryptic juvenile starfish (1+ year old). On the Great Barrier Reef, fine-scale monitoring of A. planci has detected early signs of developing outbreaks some 12 to 24 months before the outbreaks became obvious to untrained divers. Reef users in the Great Barrier Reef Marine Park are already benefiting from the improved early warning capacity of the fine-scale surveys. Reef-based tourism operations on A. planci affected reefs have been able to initiate local-scale control measures before starfish outbreaks had developed their full potential, thereby reducing the loss of live hard coral cover. Injecting starfish with an environmentally-acceptable compound - sodium bisulphate - has been shown to be the most efficient method for protecting small reef sites of particular importance.

Current outbreaks of A. planci are not confined to the Great Barrier Reef. Recent reports suggest that outbreaking populations are now appearing on many reef systems in the Indo-Pacific region. The geographically widespread nature and apparent synchrony of these events suggests that a truly large-scale phenomenon may provide the initial trigger. Applying the fine-scale survey methodology outlined here may greatly assist in the early detection of similar trends on other Indo-Pacific reefs with a known history of A. planci outbreaks.

cleractinian coral cover on reefs around Rota, Saipan and Tinian was substantially reduced by the crown-of-thorns starfish (Acanthaster planci) in the 1960s. Following the outbreak, coral cover on the outer reef slope to the western side of Saipan was estimated to be between 5 and 60%, with 50 to 98% of that dead. Twenty-seven years after the outbreak coral cover on many reefs remains below pre-outbreak levels. Many of the reefs had become dominated by Porites rus, a non-preferred prey species. Acanthaster planci and Culcita noveaguinea were present in low densities along most of the reefs surveyed on Rota, Saipan and Tinian. Larval recruitment rates were very low suggesting that much of the recruitment occurs asexually. The low larval recruitment rates for the Northern Mariana Islands in comparison with those observed along the Great Barrier Reef suggest that coastal zone managers in the Commonwealth of the Northern Mariana Islands need to look with increased caution at activities which are likely to affect the reefs. Although the reefs around Saipan have recovered from war and an A. planci invasion, it does not appear that larval recruitment has contributed much to the recovery. The species diversity is not likely to be either maintained or increased swiftly by larval recruitment brought in by water currents. We postulate that the Northern Mariana Islands coral reefs of Rota, Saipan and Tinian provided some of the recruits for the recovery of Guam reefs.

COTSWATCH

For 1997, the 'vital statistics' up to and including 29 September 1997 read as follows - 431 completed reports have been received, providing details on 761 individual sites from 108 different reefs.

As usual, my sincere thanks to all contributors for continuing to support this valuable scheme. 1997 COTSWATCHERS to date are: A Ballard / Townsville; A Crabtree / Port Douglas; A Lloyd / Ingham; A Payne / Captain Cook Cruises, Cairns; AB Petith, AB Davis, AB Warren / RAN, HMAS Cairns; A Knight / Quicksilver Connections; B Astill / HMAS Cairns; B Knuckey / DoE Gladstone; B Jewel / Cairns; C Coxon / Cairns; C Davies / Cairns; CJ Piper / Lane Cove; C MacKenzie / Sydney; C McCokell / HMAS Cairns; C Purdon / DoE Townsville; C Smith / Townsville; CPO D Hamilton-Thompson / HMAS Tobruk; Cairns Dive Centre/ Cairns; C Bartello, N Roper, A Kelly, D Schappendonk, S Wilson, S Payne, P Paxton, I Davis, D Hicks, D Kusnezow, D Anderson, M Woodhouse, T Lace, W Pearce, J Purcell, J Lackinosh / Great Diving Adventures, Cairns; D Brooks / Townsville; D Clements / Townsville; D Conwell / North Epping; D Pennell / Andergrove; D Wachenfeld / Undersea Explorer; D Wiseman / Sunlover Cruises; Dive Team / HMAS Brisbane; The Diving Officer / HMS Gloucester UK; Dungeness Marine Park Base / Lucinda; E Hardman / Birmingham UK; F Helligman / Lady Elliot Island; F Gunst / HMAS Cairns; F Soper / Brinsmead; F Muir / DoE Cairns; Friendship Cruises / Mission Beach; GA Conwell / North Epping; G Burns / Roseville; G Blazinic / Port Douglas; Greg Smith / Townsville; H Bailey / Captain Cook Cruises, Cairns; H Malcolm / DoE Townsville; R Buck / DoE Mackay; IR Fleetwood / Gladstone; I Stapleton / Nimrod Cruises, Cairns; I Bachtiar / FKIP Universitas Mataram, Indonesia; J Curtin / DoE Cairns; J Jones / HMAS Cairns; J Lothian / Reef Biosearch, Port Douglas; J Money / HMAS Cairns; J Oliver / Townsville; Jill Thorsborne / Cardwell; Jim McKenzie-Smith / Endeavour Diving Services, Cooktown; K Wallis / Magnetic Island; Kai Hoppe / Kiel Germany; L Whiteley / Seascape Charters, Townsville; Lady Elliott Island Resort; L Bright / Townsville; M Abela / Pure Pleasure Cruises, Townsville; M Cunningham / Innisfail; M Puotinen / Townsville; M Earney / Mackay Adventure Divers, Mackay; M Watterson / Innisfail; M Greet / Port Douglas Dive Centre; M Allen / FV Seafari, Cairns; M Mathews / Undersea Explorer; N Munro / Sixteen South Charters, Port Douglas; N Heath / Aspley; Ocean Spirit Cruises / Cairns; P Bikaunieks / Kewarra Beach; P Erasmus / Kangaroo Explorer, Cairns; P Heatherwick / Port Douglas; P Daniel / DPI Qld; Port Douglas Dive Centre / Port Douglas; R Avery / Menai; R Loudon / HMAS Cairns; RD Sluka / Oceanographic Society of Maldives, Republic of Maldives; R Lewis / Big Cat Dive, Cairns; R Berkelmans / Townsville; R Taube / Kelvin Grove; S Balson / DoE Cardwell; S Johnson / Townsville; S Martin / DoE Cairns; S Moon / Ocean Spirit Cruises, Cairns; S Wilson / Cairns; S & G Ellaby / Sunlover Cruises; S Wood / Friendship Cruises, Mission Beach; S Zannino / Gladstone; T Adami / Townsville; Great Diving Adventures / Cairns; T Sheaves / HMAS Protector; V Eiter / Townsville.

COTSWATCH - INTERNATIONAL

Following the publication of a small promotional article in the June/July issue of 'Asian Diver', expansion of the COTS program on to the international arena is well under way. A slow trickle of reports from overseas locations is now coming in, with many of the new contributors to 'COTSWATCH - International' indicating their willingness to provide regular reports and updates on their respective reef areas.

Similar to the October 1993 launch of 'COTSWATCH' in Australia, I anticipate a somewhat slow start followed by a more rapid expansion of the scheme as our network of new observers increases.

Recent reports from overseas have confirmed the existence of current COTS outbreaks on quite a few reef systems in both the Indian as well as the Pacific Ocean. For example, verified records have come in from the Seychelles, Mauritius, Indonesia, Malaysia, the Philippines, the Solomon Islands, Fiji and the Cook Islands. Many of these outbreak reports were accompanied by requests for further information on how to design and implement a local strategy for the control of the outbreaks. As such, 'COTSWATCH - International' is already facilitating the regular exchange of information between geographically isolated parties affected in similar ways by the COTS phenomenon.

Some of the figures provided by overseas observers are quite impressive to say the least. For example, local control measures in parts of Indonesia have resulted in the removal of more than 13 000 COTS over a four-month period from just a few small fringing reef areas.

To make COTSWATCH reporting a little bit easier for those who are already connected to the wonderful world of the Web, survey reports can now be submitted electronically using our new Web site located at
http://www.gbrmpa.gov.au/cots