Why the Humphead Wrasse Is Endangered

With its distinct forehead bulge and striking bright blue, green, and yellow colors, the endangered humphead wrasse is certainly hard to miss. These colossal coral reef fish, found across the Indo-Pacific, weigh in at over 400 pounds and can grow to over six feet long. Unfortunately, the humphead wrasse is also considered a delicacy in places like Hong Kong and mainland China, and has become a victim of widespread illegal fishing as a result.

The International Union for Conservation of Nature (IUCN), which first placed the humphead wrasse on the endangered list in 2004, estimates between 2.5 and 3.5 adults per 8,000 square meters on Australia’s Queensland reefs and about 10 fish per 10,000 square meters throughout the rest of its range. In 2005, CITES listed the humphead wrasse in Appendix II to regulate its international trade by issuing export permits in source countries.

Learn all about this amazing endangered species and what is being done to help the remaining population survive.

Threats

The humphead wrasse is primarily vulnerable to destructive overfishing practices and illegal fishing due to its high value in Southeast Asia’s live reef fish trade. As members of coral reef ecosystems, the species is also threatened by climate-related issues like increased ocean temperatures and rising sea levels.

Destructive Fishing Practices

Traditional methods for capturing humphead wrasses included hook and line, hand spear, trap, or, more recently, speargun using diving tanks. Since the fish are so massive and difficult to catch, divers typically hunt at night or focus on smaller, more juvenile fish.

In some areas, fishers use a destructive method where they expose fish to cyanide poison to knock them out, then quickly remove them into freshwater. The cyanide that remains in the environment can kill corals and cause bycatch death among marine animals exposed to the poison but not removed in time. Studies show that this method may result in irreversible ecological damage in Indo-Pacific coral reef systems, especially when combined with the impacts of climate change.

Illegal Trade

Despite its protection from CITES, the humphead wrasse is still hunted and sold illegally throughout its range. Traffic surveys conducted in 2015 found at least 15 companies selling live, chilled, or frozen humphead wrasse, 12 of them in mainland China.

In Hong Kong, surveys in the region’s three largest fish markets discovered a total of 1,197 live humphead wrasses for sale between November 2014 and December 2015 alone. However, Hong Kong’s Agriculture, Fisheries and Conservation Department and CITES Management Authority recorded the import of just 150 humphead wrasses during 2014.

Climate Change

Climate change affects the humphead wrasse's habitat in several ways. Primarily, warming ocean temperatures can contribute to changing ocean chemistry and higher risks of coral bleaching, disease, and toxic algae blooms. As the ocean warms and sea levels rise due to added water from melting ice sheets and thermal seawater expansion, it may lead to destructive erosion and increases in sedimentation for reefs located near land.

Sea levels on the Great Barrier Reef have already risen 3 millimeters per year since 1991. The Intergovernmental Panel on Climate Change predicts that global sea levels will rise by 26 to 29 centimeters before 2030.

What We Can Do

The evidence shows that humphead wrasses are still being taken illegally from their habitats and could benefit from legislative changes, increased law enforcement, or stricter regulations. Fish trading networks are difficult to track, so conservationists have had to turn to more creative approaches. 

In 2011, a project based in Malaysia aimed at curbing the export of humphead wrasse initiated a “buyback” program for wrasses that were intended for sale. The fish were purchased from markets and strategically released back into the wild in hopes that they would repopulate coral reef ecosystems. Since the program began, a total of 874 live humphead wrasses have been purchased and released at four different sites off the coast of Malaysia.

Researchers from the University of Hong Kong are taking advantage of the humphead wrasse’s complex facial patterns by developing a new facial recognition software to identify individual fish. The software and app could help improve monitoring practices and the subsequent enforcement of illegal humphead wrasse trading. It could even apply to other marine animals with recognizable features. 

Supporting Coral Reefs

Humphead wrasses are vital to the overall health of our planet’s coral reefs. Their main diet consists of crown-of-thorns starfish, a spiny echinoderm that preys upon coral. Although these starfish are native to the same region as the humphead wrasse, the species has been known to devastate hard coral communities and is considered one of the main causes of coral loss in the Great Barrier Reef. Saving this unique species could bring about a range of positive outcomes to important reef communities that are vital to wider ecosystem-level impacts.