For a few days last November, a contingent of local scientists did their best to dazzle a visiting federal task force with the many and varied threats Hawai`i is facing as a result of increasing pressure from aquatic alien plants and animals.
As a kid, state coral reef ecologist Dave Gulko used to spear fish in Kane`ohe Bay, back when the corals were healthy and fish were more abundant. The alien algae now creeping across the bay, smothering corals and displacing the animals that live there, are just a handful of the plethora of species threatening Hawai`i’s waters.
At the Aquatic Nuisance Species Task Force meeting held last November at the Radisson Waikiki Prince Hotel, an effusive Gulko and about a dozen other representatives from the Bishop Museum, the University of Hawai`i, the state Division of Aquatic Resources, the Waikiki Aquarium, and the U.S. Fish and Wildlife Service, presented a cross-section of the main issues Hawai`i researchers and resource managers are dealing with, from shipping traffic, to aquarium releases, to cleanup efforts.
Impressed by the Hawai`i contingent’s hours-long presentation, the task force requested a proposal to form a Pacific Regional Panel, which would report to the task force, along with four other panels representing regions on the mainland.
Some Background
In the 1980s and 90s, alien aquatic species were wreaking havoc worldwide. European zebra mussels had infested in the Great Lakes and were glomming on to every hard surface they could find, killing clams and other wildlife, clogging pipes, and causing millions – now billions – of dollars in damage. The West Atlantic cone jelly had made its way to the Black Sea, where it decimated zooplankton populations and bankrupted the fishing industry. San Francisco saw the introduction of the Asian clam in October 1986. By the summer of 1997, it was the most abundant species in the bay.
Hawai`i has not yet seen invasions on this order, but it is vulnerable. University of Hawai`i professor Celia Smith says 25 percent of Hawai’i’s coral and at least that much of our algae are endemic, meaning they’re found nowhere else in the world. And 40 percent of our shallow water fish and 32 percent of our shallow invertebrates are also endemic.
According to the state Department of Land and Natural Resources’ Division of Aquatic Resources, all native Hawaiian stream fauna, plus about 20 percent of the invertebrate and 25 percent of the fish species on Hawaiian reefs are endemic. And because of our high endemism rates, alien aquatic species are a particularly menacing threat here and researchers are taking steps to prevent their spread. For example, says Gulko with the Division of Aquatic Resources, since 2001, ten scientific expeditions have been made to the Northwestern Hawaiian Islands. A lot of the equipment used was based Kane’ohe Bay, which is plagues with alien algae. To prevent the accidental introduction of species from Kane`ohe to the Northwestern Hawaiian Islands, the U.S. Fish and Wildlife Service has instituted strict protocols calling for pre-departure inspections and mandatory freshwater soaking of all gear, engines, and hulls.
From dive gear to cruise ships, Hawai`i needs to be wary of what living creatures they bring with them. Aquaculture is another vector that needs to be watched. By Gulko’s count, no fewer than six companies are seeking ocean leases for aquaculture. Among the organisms aquaculturalists are proposing to raise are soft corals, which concern Gulko especially, since their stomachs can hold potentially threatening organisms.
These worldwide examples combined with the local evidence about the effects of shipping have spurred many of Hawai`i’s scientists and resource managers to redouble their efforts to prevent unwanted introductions by paying greater attention to the condition of ships, equipment, and the types of organisms that enter our waters.
A Blacklist
According to Andrew Cohen, an environmental scientist with the San Francisco Estuary Institute, in the mid-1800s, the U.S. Navy had determined that the salinity of north San Francisco Bay’s waters was too low for wood-boring Pacific coast shipworms to survive. The Navy would then not have to worry about the effects these animals might have on its ships and the bay’s wooden pilings that supported its many piers. But in 1914, the Atlantic shipworm arrived, a species more tolerant to fresh water, and by 1919, Cohen says, the worms’ presence was apparent to all: a pier fell every two weeks from being eaten away.
How would things have been different if the Navy had known in advance of the worm’s potential?
Lucius Eldredge and Donna Turgeon of Hawai`i’s Bishop Museum are in the early stages of a project that may one day address such issues. The two researchers are working on a kind of on-line Most Wanted album of verified alien aquatic species that will help early detection of possible threats.
Of the 50,000 alien species in the United States, about 600 of those are aquatic, and between 70 and 235 of these are found in the lower 48 states. Some of them can cause severe environmental and economic damage; to take the example of the zebra mussel again, cost of dealing with the problems it has caused over the last decade comes to roughly $3 billion.
In hopes of preventing such a catastrophe from occurring here, Eldredge and Turgeon propose a website listing all verified aliens – a kind of pilot warning system that could be used in doing risk assessments and predictions of those animals, and aid in the development of federal and state rapid responses and mitigation measures to be used if, despite all precautions, introductions do occur. They have been working on the project for about a year, entering those species found in Hawai`i, and hope eventually to link that with the 20,000 species archived in the databases of the National Oceanic and Atmospheric Administration, the National Coastal Data Development Center, and others.
According to Eldredge, the project grew out of inventories of alien aquatic species that the museum had done in the 1990s. The information collected is entered into a database of known alien invasive species (those established and reproducing) that will serve as a pilot warning system and be posted on its website.
Hawai`i has more than 300 coastal alien species and the pilot system will have a strong Hawaiian focus for the first several years. In the meantime, Bishop Museum will work on modifying software to allow incorporation of information from other databases. The inventory of Hawaiian alien aquatic species should be completed this spring, with a peer review of the final species list in 2004.
Shipping
Because the zebra mussel was the catalyst for much of the nation’s legislation regarding alien aquatic species, a strong focus of the movement to address aquatic aliens is on the vector that brought the mussel to the Great Lakes — ballast water. Ballast water was responsible for between 50 and 85 percent of alien introductions in San Francisco waters between 1910 and 1998, says Cohen.
It is a different story in Hawai`i, however. Here, it turns out, fouling by organisms that grow on the outside of vessels’ hulls plays a bigger role than ballast water in the introduction of alien aquatics. In his research, Eldredge found hull fouling was responsible for bringing 212 species of marine invertebrates to Hawai`i. Solid ballast and ballast water followed with 21 and 18 species, respectively.
In 1998, Scott Godwin came to Hawai`i from the Smithsonian Institute to participate in further shipping studies being conducted by the Bishop Museum. Honolulu Harbor is the major shipping hub in the Pacific, with vessels arriving from ports of call all over the world. Godwin studied 74 vessels calling on Hawai`i.
His findings, like Eldredge’s, showed hull fouling as a major vector for dispersal of established alien aquatic species. Nanosesarma minutum crab and the oyster Chama macerophylla arrived here from a floating dry dock towed to Pearl Harbor from the Philippines. Dictyota flabellata, a type of algae, came from another dry dock from San Diego. And in 1999, the U.S.S. Missouri brought with it mussels, alive and spawning, despite efforts to clean the ship before it got here. Three months after Godwin surveyed the ship, he found juveniles had settled.
On eight vessels, Godwin found 16 non-indigenous plant species, one sponge, three cnidarians (anemones), five polychate worm species, and five crustacean species.
By studying towed vessel traffic patterns, Godwin was able to trace specific alien species back to where they came from. He found that the largest source of hull-fouling species collected in his study came from the Eastern Pacific Region. “This was due to a single floating dry dock that was towed from San Diego to Barber’s Point Harbor,” his study states. He also found that previously documented alien species on O`ahu “were found regularly on interisland cargo barges. These vessels may be acting as agents for the further dispersal of some alien species to other main islands.”
As an example of this, Godwin cited a barnacle on an inter-island cargo barge that is now found on all of the main Hawaiian islands, except for the rarely visited Ni’ihau and Kaho’olawe.
According to Eldredge’s statistics, the areas with the greatest percentage of aliens are those that see a lot of traffic. Pearl Harbor has 23 percent non-indigenous species (NIS), Waikiki has 6.9 percent, Kuapa (Hawai`i Kai) has 18 percent, the south and west shores of O`ahu have 17 percent. More remote places such as Midway, Kaho`olawe, and French Frigate Shoals have hardly any invasives, with 1.5 percent, 1 percent, and two species, respectively.
From Ocean to Streams
Over the years, new marine species have come in waves coinciding with increased pulses in shipping traffic. But shipping is just one vector. According to DAR’s Mike Yamamoto, in the late 1800s, the emergence of the sugar industry brought large numbers of Asian workers to Hawai`i, and with them, some of the fish and animals they were used to eating: Japanese weather fish, Chinese catfish, snakehead, Chinese soft shell turtle, and others.
Other species were deliberately introduced by the government, like tilapia, Tahitian prawns, mosquito fish and various kinds of sportfish, including rainbow trout and large- and small-mouth bass. Even more alien aquatic species have become established via the aquarium industry, with people accidentally or deliberately releasing the contents of home aquariums into nearby streams. Annette Tagawa of DAR says that 80 to 90 percent of alien species in streams come from the aquarium trade. Some people in the industry harvest streams like Kamoli’i in Kane`ohe since “it’s easier than raising” new animals or grass, she says.
While Hawai`i has no equivalent of the zebra mussel, alien aquatics have caused problems here.
– Baby Asiatic clams, brought to Hawaiian food markets in 1997, clog irrigation systems.
– One species of armored catfish digs out nesting tunnels in stream banks, causing erosion.
– Small-mouth bass are highly aggressive and predatory and compete with native gobies. According to the book Hawai`i’s Invasive Species, by Eldredge and Robert Cowie, “native fish and crustaceans [are] almost completely absent in sections where smallmouth bass occur.”
Alien invasives have completely taken over Kamoli’i Stream on O`ahu’s windward side. Tagawa says the o’opu nakea, one of a handful of native gobies, is the only native fish found in the channelized stream. Even these are seen only occasionally, she notes.
On the other hand, on a field trip last November for visiting members of the aquatic nuisance species task force, Yamamoto and Tagawa easily captured a large armored catfish, about half a dozen Asian clams, an adult Chinese softshell turtle and a day old baby turtle, a few tilapia, about a dozen each South American catfish and ciclids and some crayfish – all in an hour and a half.
Yamamoto says that the state’s current procedures to control importation works well, “but it takes just one or a couple people” to cause a nuisance species to become established.
Algae From Hell
Like the lonely o`opu nakea in Kamoli`i Stream, life underwater at Kane’ohe Bay is becoming a nightmare for native corals, turtles, and the scientist hoping to control the alien algae that are blanketing parts of the bay with frightening speed. Kappaphycus, introduced to the north reef flat of Coconut Island in Kane’ohe Bay in 1974 for growth experiments, escaped into the bay and has covered 6 square kilometers in 25 years. It has been spotted as far north as Kualoa Beach Park in 1999.
Kappaphycus is one of several invasive algae in Hawai`i threatening the bay’s coral. Turtles are affected as well, says the DAR’s Gulko, as the algae crowd out the turtles’ sleep holes and affect their feeding habitat and mating and cleaning stations. Green sea turtles will stand on coral outcroppings and allow reef fish to nibble away, thereby getting their shells cleaned.
Kane’ohe Bay has experienced what’s called a phase shift, where a once-healthy coral reef ecosystem, dominated by reef-building corals and coralline algae, becomes dominated by macroalgae.
Unlike the worldwide problem with Culerpa taxafolia, where the algae grows in big stands over sand flats, most of Hawai`i’s alien algae grows on living coral reefs. Kappaphycus in Kane`ohe Bay is increasing at a rate of 10 percent a month and as a result, areas of exposed coral are decreasing. And when the algae is removed, the coral beneath is sick or dying.
Eric Conklin, a researcher with the University of Hawai`i, says it is testing methods to control the algae. These include increasing salinity and temperature, using herbicide and algicide, and other methods that could affect algae growth.
The first of these, Conklin says, has already been shown to have little promise. The salinity and temperature levels needed to harm the algae have turned out to be too extreme — at 80 parts per thousand sea water and 42 degrees Centigrade.
Manual removal is labor intensive, he adds, taking up to two hours to clear one square meter. To speed up the process, The Nature Conservancy is testing a suction pump to vacuum the algae off the reef.
To test regrowth rates, UH researchers have taken rock covered with Kappaphycus and scraped it off. After two months of soaking in a saltwater tank, Conklin says about 50 percent of the algae had grown back.
A native sea urchin that likes to eat Kappaphycus, Tripneustes gratilla, may be a potential tool, but it would take quite a few of them: it takes one urchin a couple of months to clear a half square meter plot.
About 19 algae species have been introduced to Hawai`i in the last 50 years, five of which have become major pests. The most common, Acanthophora spicifera, was introduced on the hull of a vessel from Guam. The next three — Hypnea musciformis from Florida, Gracilaria salicornia, and Kappaphycus – all came from aquaculture releases. Holding fifth place on the list is Avrainvillea amadelpha, which came to Hawai`i by unknown means.
A survey of 90 sites in Hawai’i found that all but one of the invasive algae thrive in high-nutrient areas. The exception, Gracilaria salicornia, can thrive in pristine reefs. Fish don’t eat it, making it all the more threatening. At present, it is commonly found in Waikiki and parts of Kane’ohe Bay. More than 30,000 pounds have been collected at Waikiki Beach, says Cindy Hunter of the Waikiki Aquarium. In species abundance studies conducted in the 1960s and 1970s, she says, more than 60 species were found there, with no one dominant species. In recent studies, the number of species has decreased to fewer than 20, with two algae dominating the area.
Other algae woes: Avrainvillea, which grows on soft bottoms, may displace native sea grass. And on Maui, foul-smelling Hypnea blooms have plagued Kihei, where the state has had to remove 20,000 pounds a week and spend $100,000 a year cleaning the beach. In addition, the state and county lose millions of dollars a year in lost rental income, decreased property values, and the like, as a result of the Kihei algae.
Moving Forward
For invertebrate alien aquatic species, things are still in the inventory stage. “We need to find out what’s here,” says Eldredge. As for the invasive algae, regarded by most as a more serious problem in Hawai`i, a lot of work is being done to control or eradicate them. “With fish,” he says, “it’s a matter of waiting to see what’s here.”
With their presentations to the task force, Eldredge and his peers laid the groundwork for more and continued federal support. The Federal Aquatic Nuisance Species (ANS) Task Force, an organization set up by the federal Nonindigenous Aquatic Nuisance Prevention and Control Act (NANPCA) of 1990, is dedicated to preventing and controlling aquatic nuisance species, implementing NANPCA and National Invasive Species Act.
If the task force approves Hawai`i’s proposal for a Pacific regional panel, Eldredge says it would put Hawai`i’s problems – and those of other Pacific islands – on a national level and make them eligible for greater federal support. “Not buckets and buckets, but some money.”
On the local front, the Division of Aquatic Resources, which has its own task force to deal with alien aquatic species, has Paul Murakawa heading up a ballast water and fouling program. Murakawa is also preparing a ballast water and fouling section that will be part of a Hawai`i alien aquatic species management plan being prepared by The Nature Conservancy of Hawai`i’s Scott Atkinson and Andrea Shluker. When finished, the plan will be submitted to the state Board of Land and Natural Resources for approval.
— Teresa Dawson
Volume 13, Number 7 January 2003
Leave a Reply