17 March 2014

Lionfish kingdom

by Ali Hendren

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Over the past 25 years, an outbreak of invasive lionfish has swept across the Caribbean, along the Gulf coast and even up into North America’s eastern seaboard. Faced with dwindling natural predators and bountiful prey, it is now widely believed that the lionfish epidemic has spread beyond the point where human intervention will have any significant effect, according to the International Coral Reef Initiative. Most likely introduced via aquarium discharge, whether intentionally or not, the lionfish have now taken over Caribbean waters.

“Their voracious appetite and the absence of natural predators have made them a threat to the ecological balance of the Caribbean reefs,” says Alexis Peña, a marine biologist with Panama’s National Authority of Aquatic Resources. His country has teamed up with the Smithsonian Tropical Research Institute to educate locals on the havoc the prickly fish are wreaking on the Caribbean. Peña’s team has also organized fishing tournaments in hopes that netting—and eating—lionfish will catch on.

In Costa Rica’s Caribbean fishery, officials have reported an 80 to 87 percent reduction in fishing yields that they attribute, at least in part, to lionfish. Native to the Indian and Pacific tropics, lionfish (Pterois volitans) are voracious predators, feeding on smaller fish, crabs, shrimp and lobsters. Equipped with long, spines that reach out in all directions, lionfish slowly cruise along coral reefs seemingly without fear of predators. The moray eels, sharks and grouper that are known to eat them all too often pass over lionfish for less prickly prey. To boot, the spines are venomous and can cause paralysis in humans in the worst cases.

Protecting these coastal ecosystems are important to countries like Panama and Costa Rica—a healthy fishery is not only important to locals as a food source but is also a draw for tourists interested in scuba diving and sport fishing.

So why can’t we just fish for them? Unfortunately it’s not that easy. When not out scouring the reef, lionfish live in caves and cracks out of reach of traditional fishing nets and while they are voracious and insatiable eaters, fishing with a hook-and-line tends to catch a lot of other reef predators too. Scientific submarine expeditions, like OceanGate and Nemo, have found Lionfish at depths of 70 meters and 300 meters respectively (230 and 1000 feet).

One of the most promising options lies in targeting individuals for removal by hand. But even spear fishing isn’t without its drawbacks:

  • Spear fishing is labor-intensive, requires training / certification and it is expensive to get divers in the water (boat, equipment, fuel);
  • Divers can only be underwater for a limited time and at limited depths;
  • Snorklers, can spend more time in the water but are limited to only shallow areas;
  • Populations of fish outside of divers’ reach — laterally outside of the patrolled area or at greater depth — can repopulate an area quickly;
  • The market for lionfish meat for human consumption is not strong enough to support a fishery.
  • Spear fishing while scuba diving is banned in places like the Bahamas.

 

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Learn as you go

While removing lionfish by hand off of select reefs may be a short-term strategy for high-value habitats, that methodology has no end-point if more lionfish invade. Female lionfish each lay 12,000 to 15,000 eggs at a time and can breed every four to five days, totaling more than two million eggs per year per sexually mature female. It’s no wonder they have spread like wildfire.

“Successful control of invasive lionfish requires adaptive management,” saysLad Atkins, director of special projects for the ocean conservation organization REEF. A buzzphrase in conservation circles, adaptive management is a systemic approach that continually learns from outcomes as policies are implemented.

This is the format of a new endeavor between Costa Rica and Mexico’s Regional Lionfish Committee for the Caribbean and the Commission of Natural Protected Areas of Mexico (CONANP). The initiative intends to monitor, prevent and control the spread of lionfish in their coastal waters. Instead of hosting spearfishing derbiestraining local sharks or promoting a market for lionfish meat as has been tried before, Costa Rican officials are hoping an ecosystem-based program will restore balance to the ecosystem.

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The USGS has been collecting lionfish sightings since 1992. http://nas.er.usgs.gov/taxgroup/fish/lionfishdistribution.aspx

Eating lionfish

One of the many prongs of attack for Costa Rican officials will be the continued promotion of a fishery and market for lionfish meat. Researchers from Oregon State University have data from computer models based on field experiments in the Bahamas that suggest that a 75% to 95% reduction in local lionfish will allow native fish populations to rebound.

This plan will require substantial human effort and local buy-in as well as incentives for fishermen in the form of a local or export market. Lionfish is consumed as a traditional delicacy in Japan where it is known as gashira or mino kasago. In the United States, some restaurants are servingdomestically caught lionfish as part of a budding “invasivore” movement.

“It must be delicious,” says Tadashi Kimura, chief researcher of the Japan Wildlife Research Center in Tokyo. “But I do not recommend more countries eating the lionfish.” Kimura says the choice depends on personal taste and culture. Though Japan happens to eat lionfish, forcing another country to eat the fish may not be the best way to exploit this resource. In the end, Kimura says, monitoring the effects of lionfish on fisheries like the Caribbean’s is important for preventing future invasions that are bound to come.

“The challenge of lionfish in the Caribbean will provide us more important information for other countries [to] learn.”

Additional reporting by Aleszu Bajak.

 

Also published with more photos up on Medium.

 

 

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Ali Hendren is interested in the marine environment and has worked towards its conservation and management, tackling research projects on the East and West coasts and the Gulf of Mexico. He has a master’s degree in environmental science and policy from George Mason University. Follow him on Twitter @SkiSkillz.