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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.


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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.


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