New Report Finds Hazardous, Aggressive Aquatic Species Wreaking Havoc in World’s Oceans and Coasts

First Ever Global Maps Reveal Spread and Severity of Marine Invasive Species

HONOLULU, HAWAI'I — February 19, 2008 — Eighty-four percent of the world’s coasts – including those in Hawai‘i – are being affected by foreign aquatic species, according to a new Nature Conservancy study published today in the journal Frontiers in Ecology and the Environment.

This study represents the first quantitative global assessment of the impacts and causes of marine invasive species, and evaluates where they are located, how they are transported, and which species are the most harmful to native habitats.

Hawai‘i is named as an ecoregion with high levels of invasion, with 73 marine invasive species, 42 percent of which are considered harmful and are disrupting multiple species or wider ecosystems. San Francisco tops the list with 85 species, 66 percent considered harmful. (The study only includes species for which there is scientific data available on the ecological impact, and local scientists believe there may be many more marine invasive species in Hawai‘i.)

Likely pathways for the spread of these invasive species in Hawai‘i are shipping (68 percent) and aquaculture (39 percent), according to the study.

Kane'ohe reefs choked with Eucheuma algae

Kāne'ohe reefs choked by the invasive algae, Eucheuma.
Photo © Jennifer Smith.

“Many in Hawai‘i have seen what alien algae have done to some of our reefs. We need all the tools that can be provided for wise management of our coasts,” said Celia Smith, a professor and seaweed specialist in the University of Hawaii's Botany Department. “Our next concern is that reefs in other parts of the Pacific may be similarly impacted but have no scientists there to help.”

Scientists in Hawai‘i say invasive algae are a growing threat to reefs. An effective tool in combating invasive algae in Hawai‘i is the Super Sucker, a mechanical removal device that acts as an underwater vacuum cleaner to take invasive algae – such as smothering algae (Eucheuma denticulatum) and gorillo ogo (Gracilaria salicornia) – off the reef. The full-size device can scoop up about 800 pounds of algae an hour.

Currently, there are two bills – HB 2828 and SB 2638 – moving through the State Legislature that, if passed, will appropriate funds for the full-time operation of the Super Sucker in Kāne‘ohe Bay for one year and for purchase of a portable unit.

Divers use Super Sucker to vacuum alien algae off reefs. Photo © Kanako Uchino.

"The Super Sucker is an essential component of a comprehensive management strategy for controlling these alien algae,” said Eric Conklin, marine science advisor at The Nature Conservancy in Hawai‘i. “The research we’ve done shows that we can efficiently remove mass quantities of algae from impacted reefs. In some cases, we can restore the reef to a condition that native fishes are able to maintain in an algae-free state, which allows corals to recover.”

Invasive species are non-native species that have been introduced into a new landscape, freshwater system or ocean region. Because this new area often lacks natural competitors and predators, the invasive species tend to displace native plants and animals, disrupt food webs, and alter fundamental natural environmental processes.

“Everyone in the world depends on healthy oceans and coasts for survival. Invasive species are severely impacting native plants and animals, and are causing significant economic damage at the same time,” said Stephanie Meeks, acting president and CEO of The Nature Conservancy. “By understanding the scale and scope of these invaders, we are better equipped to stop them.”

The economic costs of invasive species, including marine invaders, can also be huge. The U.S. spends $120 billion annually to control and repair damage from the country’s more than 800 invaders. Throughout the world’s oceans, aquatic alien invasives damage economies by diminishing fisheries, fouling ships’ hulls, and clogging intake pipes. Some can even directly impact human health by causing disease.

The study cites many examples of this damage, such as the comb jellyfish that was carried to the Black Sea on a ship in the early 1990s. By feeding voraciously on fish eggs and zooplankton, they devastated fish populations and disrupted the entire food chain. At its peak, this plague made up 90 percent of the weight of all living organisms in the Black Sea. When the comb jelly invasion later reached the Caspian Sea, it again diminished fish populations and left the threatened Caspian seal both hungry and vulnerable. Both of these invasions destroyed commercial fisheries and caused coastal communities to lose thousands of jobs.

“The scale of this problem is vast,” said Jennifer Molnar, conservation scientist at The Nature Conservancy and lead author of the study. “Every day, thousands of vessels cross our oceans with invasive species hitchhiking on their hulls. Because of this, as many as ten thousand species are estimated to be in transit at any one time.”

According to the study, international shipping and aquaculture represent the major means of harmful species introduction world-wide, and 80 percent of all invasives introductions are accidental. Other specific findings from the study include:

Prized for their plump meat, Pacific oysters have been transported from Japan to be farmed in coastal waters around the world since the early 1900s. Once introduced, they aggressively attach themselves to rocks and group together, squeezing out other species. In Australia and elsewhere, this fast-growing species can smother prized native oysters and mussels, hurting local fisheries.
Caulerpa, a tropical seaweed that has wreaked havoc in the Mediterranean and in Australia, is transported on the anchors of fishing and recreational boats. It is toxic to many fish and spreads rapidly, eliminating native seagrass. When a population was discovered in a California harbor in 2000, divers needed six years and over $4 million to eradicate the species.
Native salmon stocks in Scotland and Scandinavia are being decimated by new pathogens, while escaped farm salmon are weakening the genetic resilience of wild salmon. Each year, up to half a million salmon escape from fish farms in Norway alone.
San Francisco Bay, California, is the most invaded aquatic region on earth. More than half of its fish and most of its bottom-dwelling organisms are not native to the Bay, and new species are being introduced at an alarming rate.

Burlap bags full of alien algae sucked off coral reefs

The alien algae is packed into sacks and delivered to taro farmers for use as fertilizer.

The study, “Assessing the Global Threat of Invasive Species to Marine Biodiversity,” analyzes the problem on a global scale by synthesizing information on 329 aquatic species and drawing information from over 350 data sources. The report is also accompanied by a geographically referenced and publicly available database of marine invaders that can be used to determine the most threatening species per region, and to prioritize strategies for preventing further damage.

“Once alien species become established in marine habitats, it can be nearly impossible to remove them,” added Molnar. “The best way to address these invaders is to prevent their arrival or introduction in the first place.”

The Nature Conservancy is working as part of the Global Invasive Species Programme, a coalition of four leading international environmental organizations, to stop further introductions of marine invasive species through pathways such as the discharge of ballast water, which ships carry for stability, and the bio-fouling of ships hulls, which occurs when aquatic species hitchhike to new places on the bottom of ships. The Conservancy is working around the globe to advise policymakers on how to develop prevention strategies at ports and on shipping vessels.

More information on the report can be found at www.nature.org/marineinvasions.
For more information on Super Sucker, go to www.nature.org/wherewework/northamerica/states/hawaii/projectprofiles/art22268.html

The Nature Conservancy is a leading conservation organization working around the world to protect ecologically important lands and waters for nature and people. To date, the Conservancy and its more than one million members have been responsible for the protection of more than 15 million acres in the United States and have helped preserve more than 102 million acres in Latin America, the Caribbean, Asia and the Pacific. Visit The Nature Conservancy on the Web at www.nature.org.