A Decade of Diving Palau’s Spawning Aggregations

Text and Images by Richard Barnden

It’s been 10 years nearly to the day since I sat down and wrote my last article for Asian Diver magazine, Scuba Diver AUSTRALASIA’s sister title. Lots of things have changed in the intervening years, but one thing remains the same – my love for diving in Palau and my fascination for spawning aggregations.

10 YEARS OF LESSONS AND DISCOVERIES

When I wrote my first story for Asian Diver, I had only really just started to understand these spawning events. Back then, I thought I had itall dialled in, but as usual, Mother Nature loves to show us who’s boss and I have been humbled many times in the process. So here are my thoughts and discoveries from a decade of diving Palau’s spawning aggregations.

PLANNING DIVES AROUND LUNAR PHASES

I have been fortunate enough to dive in Palau for more than 20 years. I have yet to get bored of diving here with the number and diversity of dive sites. But the real attraction that keeps me coming back year after year is the predictability of certain spawning events. The more you start to learn and understand these events, the better the diving becomes each year when you start piecing together itineraries based around these lunar phases.

WHAT ARE SPAWNING AGGREGATIONS?

A spawning aggregation is a natural phenomenon that occurs when a group of fish or other marine organisms gather together in a specific location for the purpose of reproduction and continuing their species. These aggregations can range in size from just a few hundred individuals to thousands and thousands of fish, and they occur in the same location year after year. The timing of these aggregations is often linked to lunar cycles and other environmental factors, like tide, temperature of the water, and sunlight. Over the last decade, Palau has become very popular in discovering these aggregations and some of these unique itineraries even offering combo spawning trips targeting multiple species in one trip.

Twinspot snapper spawning

UNIQUE PALAU

The people of Palau have always had a special understanding of spawning aggregations from very early on. Even before Western scientists came to the island to study Palau’s diverse marine ecosystems, there have been legends carved in wooden storyboards describing the predictability of marine life around lunar cycles and the dangers of overfishing. Through this local guidance and extensive knowledge shared from the Palauans, researchers have been able to gain a better understanding of the behaviour and ecology as well as the importance of spawning aggregations in the overall health of the local marine ecosystem. This research has also helped to raise awareness about the need to protect these important natural resources from overfishing, especially during these vulnerable times of spawning.

THE PALAU PROTECTED SPECIES ACT

Palau first protected the bumphead parrotfish (Bolbometopon muricatum) along with Napoleon wrasse (Cheilinus undulatus) in 2009, when the country’s government listed the species under their Protected Species Act. This made it illegal to catch, sell, or possess these fish in Palauan waters. In addition, Palau also implemented a number of other conservation measures to protect the species and its spawning aggregations, implementing a no-take zone in the area where the bumphad parrotfish aggregation occurs, prohibiting fishing and other activities that could disturb the fish during their spawning months.

A bull shark on the prowl during the spawning

A LEADER IN MARINE RESOURCE PROTECTION

That same year, in September 2009, Palau was also the first country in the world to start a shark sanctuary, covering an area of 800,000 square kilometres and prohibiting all commercial shark fishing in Palauan waters. Through these conservation measures, Palau has become a leader in protecting its marine resources. The country’s efforts have been recognised internationally, and Palau has received praise for its commitment to marine conservation and sustainability.

I always ask myself why Palau has such large schools of fish, and why there seems to be far more spawning aggregations than anywhere else in the world. Is this due to the fact that Palau has protected its aggregations for so long or is Palau just blessed? Maybe it is a bit of both.

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Scuba Diver oceanplanet No.126