It Came From the Ala Wai: 6 Strange Creatures That Thrive in Waikīkī’s Sewage Filled Canal

What lurks in the murk of Honolulu’s most prominent drainage ditch? Lots of things, including a fish that can literally give you nightmares.
Photos: Elyse Butler Mallams

An old film clip in the archives of the Bishop Museum shows a group of children and adults, in early 20th-century swimwear, frolicking in the waters of the Ala Wai Canal. It probably dates to the 1920s, the same decade the two-mile-long canal was dug to drain Waikiki’s wetlands and create more buildable ground there.


People don’t swim in the Ala Wai anymore. Contact with its murky water—filled with bacteria, heavy metals, pesticides, and who knows what else—can be hazardous to your health. As the dedicated canoe paddlers who practice on the Ala Wai are well aware, even light splashes can cause rashes, boils and gastro-intestinal troubles.


As scary as the Ala Wai’s waters are, life thrives there. Sure, the canal is a massive drainage ditch for a swath of city stretching from Punchbowl to Diamond Head. But it’s also a tropical tidal estuary, where freshwater and seawater meet, producing a fruitful habitat for a wide variety of pollution-resistant fish, crustaceans and other creatures.


“It may be a toxic soup,” says Alan Friedlander, a National Geographic scientist specializing in coral reef ecology, “but it supports an awful lot of life.”


Friedlander walked the Ala Wai’s banks with us in an informal biological survey, helping us find a half dozen of those hardy, foul-water-loving life forms.


SEE ALSO: Take a Closer Look at a Mud Ball Designed to Clean Up Hawai‘i’s Most Polluted Waterway

Olivia Nigro takes a water sample.



The Ala Wai teems with bacteria, much of it originating in the intestinal tracts of the rats, dogs, mongoose and other animals that inhabit parts of Honolulu and its watershed that drain into the canal. These visiting microbes are dead-enders, washed into the Ala Wai but unable to reproduce there. There is, however, a type of bacteria that calls the Ala Wai home: Vibrio vulnificus.


This sinister-sounding pathogen is a natural part of estuaries such as the Ala Wai, one which can cause serious illness if it is ingested or enters an open wound. People with chronic disease are especially at risk. V. vulnificus gained notoriety in 2006, afer a man with chronic alcoholic liver disease died of a flesh-eating vibrio infection following a dunking in the Ala Wai. The immersion occurred the same week that a sewer line failed, forcing the city to dump 48 million gallons of raw sewage into the canal. But as V. vulnificus itself is not carried by human waste, the man’s vibrio infection may have been coincidental to the sewage, says Olivia Nigro, a microbrial oceanographer at the University of Hawaii, who was involved in testing the Ala Wai for vibrio following the spill.


Nigro returned to the Ala Wai in 2008 and 2009 to conduct a year-long study of V. vulnificus. She found that vibrio levels are significantly higher in the rainy months, from December through April. But even then levels varied greatly. Sudden rains sending fast-moving fresh water into the canal were followed by reduced levels of vibrio, while soaking mountain rains that produced long, slow influxes of fresh water into the canal brought the highest levels of vibrio—sometimes hundreds of times higher than they were after the sewage spill. “After a big rain, the Ala Wai looks very brown and dirty,” Nigro says. “But that’s not necessarily when the waters are most dangerous in terms of V. vulnificus.”


Vibrio vulnificus under the microscope.


Billy Roehl fishes for Ala Wai seahorses.
Photos: Elyse Butler Mallams



One of the lesser-known creatures living in the Ala Wai Canal hides in plain sight. The endemic Hawaiian seahorse is a master of disguise. In the Ala Wai it wears the same scum-brown algae that covers the rocks, bicycle frames and other debris it clings to with its prehensile tail. Although these animals can grow up to 8 inches long, you could be staring right at one, just beneath the surface, and not realize it was there.


Someone who has developed an eye for spotting seahorses in the Ala Wai is Billy Roehl, a marine-science student at UH.  In preparation for a master’s thesis centered on Hawaiian seahorses, Roehl needed to learn how to breed them in captivity. But first he had to find some to breed. He had heard rumors of seahorses in the Ala Wai, but he couldn’t find them there himself. Then he met a homeless fisherman, who claimed he would catch a seahorse for Roehl in exchange for a 40-ounce bottle of beer and a pack of cigarettes. Within 15 minutes, the man had a bucket with a live seahorse in it. By the time Roehl returned from the store with the beer and cigarettes, the man had three more seahorses in the bucket, earning three more bottles of Pabst Blue Ribbon and three more packs of Marlboro reds.


Roehl bought seahorses from the man several more times, before the man eventually taught Roehl how to find them himself. Roehl can now be periodically found reaching into the canal for something passersby cannot see. A woman once dropped 35 cents into the empty peanut butter jar he uses to hold his catch. “I think she thought I was a crazy person, because I was lying in the mud, reaching into the water saying, ‘Come here, you!’” Roehl recalls. “I gave her a pretty dirty look, and she slinked away quickly.”




Summertime on the Ala Wai means love time for tilapia.


Of all the Ala Wai’s fishes, the indestructible tilapia appear to be the most abundant. Unbothered by the low levels of oxygen and high levels of contaminants, they spend their lives happily munching on green-brown algae that grows on everything below the waterline, jealously guarding their territories from other tilapia and breeding like crazy.


While tilapia reproduce year round, they step it up in the summer. If you had magic glasses that allowed you to see through the cloudy water to the bottom of the Ala Wai, you might see the doughnut-shaped burrows the tilapia dig in the muck to lay their eggs. In the summertime, parts of the Ala Wai resemble giant doughnut spills, with one male tilapia hovering over each doughnut, guarding it fiercely.


The newly hatched tilapia spend a week or more inside the doughnut hole, until the father gives them the OK to go. If one tries to slip out early, the father slurps it up and spits it back into the nest.


Tilapia were first brought to Hawaii in 1951, partly to serve as live bait fish for the tuna-fishing industry, partly as a food fish and partly to clean the algae from plantation irrigation ditches. Their tendency to dive when confronted by tuna, thereby luring the tuna away from the fishermen trying to catch them, made them a failure as bait. But their willingness to take bait has delighted generations of recreational fishermen, and their endless appetite for algae has made them a winner in Hawaii’s nastiest waterways.


Photo: Courtesy Roy Caldwell


Mantis Shrimp

The Ala Wai Canal appears only once in the annals of Hawaii fishing records. It’s the site where the state’s largest mantis shrimp was caught, a 1.35-pound, 15-inch-long giant.


The monster-sized stomapod (it’s not a true shrimp) was caught with the most unconventional fishing tackle: a Caterpillar 345B model crane mounted on a barge. The fisherman, Keith Harvey, was a member of the dredging crew that removed two decades of silt, shopping carts and other junk from the Ala Wai in 2003, the last time the canal was dredged. Harvey’s record setter was one of five mantis shrimp he found flopping around in the malodorous muck pulled up from the bottom.


Mantis shrimp spend most of their lives in their muddy burrows, waiting for soft-bodied prey to happen by. They are renowned for the lightning-quick blows they deliver with their knife-like appendages, which fold up like the forelimbs of a praying mantis. In fact, they are known for having the fastest strike in the animal kingdom.


Mantis shrimp are considered a delicacy in the South Pacific, but their insectlike bodies don’t have much plate appeal in the Northern Hemisphere. Harvey’s catch, and what he did with it, was such an odd story it caught the attention of The New York Times, which reported on “murderous, google-eyed crustaceans with barbed spears and
razor-switchblade appendages … captured in the shallow waters off Waikiki.” Harvey told the Times he initially planned to keep his mantis shrimp as a pet, then changed his mind and ate it. “It was really sweet,” he said.



The largest creature regularly seen in the Ala Wai is the porcupine fish, which grows up to 2 feet long and can inflate to twice its usual diameter when spooked.


Porcupine fish have beaklike front teeth and powerful jaws, good for feeding on hard-shelled prey, such as crabs. Their jaws are so powerful they can snip through wire-mesh crab traps, allowing the porcupines to dine on whatever bait or crabs they find within, and making them the eternal enemy of the Ala Wai’s hard-luck crab fishermen.


For protection, porcupines rely on their ability to puff up into big, spiky orbs. They have been found in the stomachs of large tiger sharks, but there are few other predators willing to ingest something that can essentially turn itself into a spike-covered beach ball.


That doesn’t mean the porcupines are completely safe in the Ala Wai’s sheltered waters. More than a dozen deceased, fully inflated porcupine fish were found at the mouth of the Ala Wai on the day after the 2011 Japanese tsunami generated strange currents and odd tidal fluctuations around the Hawaiian Islands. “I wasn’t able to get any specimens, so I don’t know exactly how they died,” says Thierry Work, a wildlife disease specialist with the U.S. Geological Survey’s National Wildlife Health Center, who spotted the carnage while walking his dog. Nonetheless, Work acknowledged “scared to death” was a possibility.



There is only one fish swimming in the nightmarishly foul waters of the Ala Wai that has the power to literally produce nightmares. During certain times of the year, the band-tailed goatfish—aka the nightmare weke—develops a toxin in its brain that induces terrible dreams in those who eat its head. Why this happens is a question science has not taken up, but some believe there’s an algae involved.


Hawaiian legend offers another explanation: Pahulu, chief of the ghosts.


In a version of the story recounted in Margaret Titcomb’s classic 1952 fish guide, Native Use of Fish in Hawaii, a mischievous young man named Kaululaau lies in wait for Pahulu beside a spring, hidden in a milo tree. When Pahulu arrives at the edge of the spring, Kaululaau casts his reflection upon the water, making faces at the ghostly goddess. Fooled by the reflection, she dives in to catch him, whereupon he drops a large stone on her, snuffing out her life. But her spirit escapes, leaping into the sea and living on in the nightmares of those who eat the band-tail goat fish, which is also called weke pahulu.                           


Photo: Elyse Butler Mallams



People do it, even though they really shouldn’t.


The state has a seemingly contradictory position on fishing in the Ala Wai Canal. On one hand, the state Department of Health has posted signs along the canal, stating the water is contaminated and warning the public not to fish there. On the other hand, the state Division of Aquatic Resources manages the Ala Wai as a regulated fishing area. So it’s permissible, for instance, to use a rod and reel to catch any legal-size fish in season, or to catch crabs using no more than 10 crab nets at a time.


To be sure, not everyone fishing in the Ala Wai eats what they take. Some practice catch-and-release fishing. Others catch bait to be used for fishing in cleaner waters. A state survey of fishers along the Ala Wai conducted in 1997 found that 38 percent ate their catch, prompting the Health Department to post the warning signs.


HONOLULU Magazine’s own informal survey of fishers along the Ala Wai found that most were fishing recreationally, though some were fishing for subsistence.


Of course, consuming anything that comes from the Ala Wai is a bad idea, but eating the crabs might not be quite as bad as eating other things caught there, says Alan Friedlander, a scientist specializing in coral reef ecology. That’s because crabs have an organ called the hepatopancreas, which filters toxins very effectively. The hepatopancreas is also known as “crab mustard,” and some people consider it a delicacy. “As long as you don’t eat the mustard, the meat probably isn’t that bad,” Friedlander says. “I still wouldn’t eat anything out of the Ala Wai.”


Ala Wai Timeline

1917:  Plans made to drain wetlands, rice paddies and taro patches in and around Waikiki by digging canal.

1918:  Government begins acquiring land, forcing out farmers.

1921:  Hawaiian Dredging Co. begins digging.

1928:  Digging complete. Waikiki heralded as “Venice of the Pacific.”

1929:  Warning issued: Canal unsafe for swimming.

1965:  Canal overflows, floods Waikiki.

1967:  Canal floods Waikiki again. Study looks into opening a second entrance to sea. Canal dredged for first time.

1976:  Study finds Ala Wai regularly violates federal limits on fecal coliform bacteria.

1979:  Three teens catch, eat 7-pound Samoan crab. Newspaper runs photo.

1983:  City dumps 2.5 million gallons of sewage into canal during Island-wide blackout.

1991:  Department of Health posts signs: Do not fish or swim in canal.

2002: Third dredging of canal.

2006:  48 million gallons of sewage dumped in canal; man who goes in dies of massive bacterial infection.