Bumphead parrotfish (Scarus perrico) spawning aggregation in Palau.

Bumphead Parrotfish Spawning – An Amazing Spectacle


A spawning aggregation is a predictable gathering of adult fishes for the purpose of reproduction. Many reef fish form spawning aggregations, including many grouper (Serranidae), snapper (Lutjanidae), parrotfish (Scaridae) species. Spawning aggregations can consist of tens to thousands of fish.

Bumphead parrotfish (Bolbomeotpon muricatum) aggregate to spawn around the time of the new moon in certain reef passages in Palau. The large spawning aggregations consist of hundreds of individuals. Spawning takes place in early morning.

Once organized, the school heads out from the reef into the blue.

In Palau, these large aggregations usually consist of smaller adults. Multiple males (have pale forehead) will spawn with a single female.

The amazing spectacle lasts for about one hour, before the fish separate.

Bumphead parrotfish grow over 4 feet in length and weigh over 100 lb. They play an unique role in their ecosystem, using their large beak to eat coral and algae. Each adult fish ingests over five tons of structural reef carbonates per year, contributing significantly to reef erosion.

In recent decades, overfishing led to the Palau Bumphead population shrinking, evident by a 10 fold drop in individuals landed by fishing vessels from the 1990s to 2006. This prompted the government to issue a total ban on fishing the species in 2006. And the strategy seems to be helping the population to recover. Over 60,000 Bumpheads now inhabit Palau’s reefs.


Check out the Science and Conservation of Fish Aggregations (SCRFA) to learn more about spawning aggregations and how to protect them.