Seaweed threat to Pacific coral reefs

Coral Reefs in the Pacific Ocean are at risk if ways to combat a rise in seaweed are ignored.

“Pacific reefs are more vulnerable to increases in seaweed than we used to think,” says Professor Peter Mumby from the ARC Centre of Excellence for Coral Reef Studies and UQ’s School of Biological Sciences.

“While historically seaweeds have been scarce on Pacific reefs compared to the Caribbean, we are finding that corals are pretty unprepared to cope with some of the more insidious weeds once they get a foothold.”

Evidence is mounting from the Great Barrier Reef, Palau in Micronesia, and Moorea in French Polynesia that corals avoid settling on reefs with even modest amounts of seaweed.

“Seaweeds tend to bloom when too many herbivorous fish are fished too heavily or when agricultural fertilizers pollute rivers that run into the sea. The problems are then compounded by climate change which damages corals making it easier for seaweeds to get a foothold.”

“It’s important for everyone that reefs don’t switch from corals to seaweeds. The ability of reefs to provide fisheries will at least halve if we lose the fabulous towers and hiding places created by corals.

Protecting herbivores is a practical step towards securing coral reef futures. For example, coral reefs in the Pacific would benefit from the development of fisheries regulations that regulate fisheries for herbivores so that enough fish remain to control seaweeds and limit damage to the reef. Prof Mumby’s group recently recommended regulations for the Caribbean and suggested that only 10% of the harvestable fish are taken each year and that a minimum size of 30 cm were enforced for parrotfish.

Note

Professor Mumby will present more on “Embracing a world of subtlety on coral reefs” during his Plenary talk in the Kalakaua Ballroom at the International Coral Reef Symposium in Hawaii on June 22, 2016.
Interviews with Prof. Mumby will be held 9:30am (local time) at the ICRS on June 21, 2016.

Images

Dropbox folder with images for editorial use: bit.ly/28J30Md

Contacts

Professor Peter Mumby
ARC Centre of Excellence for Coral Reef Studies
The University of Queensland’s School of Biological Sciences.
Email: p.j.mumby@uq.edu.au

Kylie Simmonds
Communications Manager
ARC Centre of Excellence for Coral Reef Studies
James Cook University, Townsville
Phone: +61 (0) 428 785 895
Email: kylie.simmonds1@jcu.edu.au