Coastal Fisheries Programme



Number 14 - October 2005

Editor and Group Coordinator: Tom Graham, PO Box 235, Honolulu, HI 96809 USA. Phone/fax: +1 (808) 625 8755

Production: Information Section, Marine Resources Division, SPC, PO BOX D5, 98848 Noumea Cedex, New Caledonia Fax (687) 263818)

Prepared with financial assistance from Australia, France and New Zealand.

From the Editor

This special issue of the bulletin is devoted to the topic of reef fish aggregations. Spawning aggregations are a fascinating phenomenon, and they are of critical importance when it comes to the challenge of managing reef fish resources effectively. This issue was compiled in recognition of that importance. Its intent is to provide a focus on the topic of reef fish aggregations, especially as they relate to fisheries for live fish, and to highlight recent progress in aggregation research and management.

The following articles document recent efforts to study and manage spawning aggregations in Papua New Guinea, Solomon Islands, Pohnpei and Palau, and they focus on the grouper species that dominate the trade in live reef food fish. The articles pay particular attention to the three groupers that are among the most valuable species in the trade and whose spawning aggregations in the Indo-Pacific tend to share the same sites and times. These three species, which make up Yvonne Sadovy’s “trysting trio” in the article that follows, are Epinephelus fuscoguttatus, E. polyphekadion and Plectropomus areolatus (with some region-specific substitutions and additions — see the articles by Sadovy and by Hamilton and coauthors).

Richard Hamilton and coauthors share some of the rich local knowledge of aggregation sites and patterns held by fishing communities in Papua New Guinea and Solomon Islands. The authors’ interviews with fishers in four study areas reveal detailed information about the dynamics and status of aggregations at no less than 50 grouper aggregation sites.

Kevin Rhodes and coauthors summarize the results from four years of underwater surveys of a grouper-trio aggregation site in Pohnpei and discuss how the results can be used to devise more effective conservation measures for aggregating fish populations.

Yvonne Sadovy and coauthors discuss various ways to track the status of aggregations over time, focusing on underwater monitoring methods. They highlight the difficulties — in terms of both survey design and practice — that must be overcome in order to obtain information that is truly valuable for management.

Finally, Terry Donaldson summarizes the ongoing aggregation studies in Micronesia, Melanesia and Asia conducted by the University of Guam Marine Laboratory and its partners.

All these articles deal with the effects of fishing on aggregations and on fish populations that aggregate. A common theme, not surprisingly, is that many aggregating populations are in trouble from fishing, and not just from live food fish fisheries. Hamilton and coauthors find that “What is more startling [than the effects of the live reef food fish trade] is the dramatic impact that recent artisanal night-time spearfishing appears to be having on [grouper aggregation sites] throughout Melanesia.” The assessment of management options provided by Rhodes and coauthors for the case of Pohnpei takes into account a similar finding: “the removal of reproductively active fish for subsistence use may equal or exceed that of commercial catch….”

In 1999, Bob Johannes and coauthors commented that “Researchers and fisheries managers in the western Atlantic have a substantial lead over those elsewhere in their employment of management measures focusing on spawning aggregations.”(1) The articles in this bulletin are evidence that this lead is eroding. Although this small collection does not represent all the recent progress in the Indo-Pacific, it reflects the growing momentum in documenting and monitoring aggregations and the increasing efforts to use the resulting information to effectively manage the region’s reef fish resources (efforts that I’m sure these authors would say are not yet enough).

Tom Graham

1. Johannes R.E., Squire L., Graham T., Sadovy Y. and Renguul H. 1999. Spawning aggregations of groupers (Serranidae) in Palau. Marine Research Series Publication No. 1. The Nature Conservancy.


Troubled times for trysting trio: Three aggregating groupers in the live reef food-fish trade
Sadovy Y. (pdf: 211 KB)
Applying local knowledge and science to the management of grouper aggregation sites in Melanesia
Hamilton R., Matawai M., Potuku T., Kama W., Lahui P., Warku J., Smith A.J. (pdf: 280 KB)
Reef fish spawning aggregation monitoring in Pohnpei, Federated States of Micronesia, in response to local management needs
Rhodes K.L., Joseph E., Mathias D., Malakai S., Kostka W., David D. (pdf: 116 KB)
Monitoring and managing spawning aggregations: Methods and challenges
Sadovy Y., Colin P., Domeier M. (pdf: 144 KB)
Reef fish spawning aggregation studies at the University of Guam Marine Laboratory
Donaldson T.J. (pdf: 64 KB)

Noteworthy publications ()


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Live Reef Fish #14 (pdf: )

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