Moku o Loe (Coconut Island) off Kaneohe Bay: What to explore and how to get there

The Hawaii Institute of Marine Biology offers Sunday tours of its research facilities on this small island on Oahu's east side.

We’re bouncing across the waters of Kaneohe Bay in a small shuttle boat I hopped on with my son at Lilipuna Pier on the east side of Oahu, speeding our way to the offshore island of Moku o Loe only a short distance away. 

The island colloquially is known as Coconut Island for its several coconut trees, which were planted here by its original owner, Princess Bernice Pauahi Bishop, for a big luau in honor of Queen Emma’s lifetime achievements. The island was made most famous, though, by its appearance in the opening credits of the television sitcom “Gilligan’s Island” and, as it just so happens, we’re going there now for a three-hour tour.  

Moku o Loe is used for marine research by the Hawaii Institute of Marine Biology (HIMB), and offers outreach programs to the public, which is why I’m here. I signed up for its Family Sunday Tour that occurs once a month, thinking that it would be filled with other parents with kids, so I brought my 10-year-old son with me. Instead, we found mostly adult couples who lived across the bay and were curious to know more about the island they see every day. Our guide, Leon, walks us around the island’s perimeter, past buildings with large tanks and explains the work being done by researchers here.

Studying the most misunderstood fish: Tilapia

“How many of you refuse to eat tilapia?” Leon asks our group of ten, walking backwards and talking loudly while pointing to a building nearby. A few people shake their heads no with a slight look of disgust, and one woman says, because tilapia have an unhealthy diet, it’s not good to eat. “You usually find them in water conditions not conducive to most fish growth and, for that reason, most people consider them to be bottom feeders, which is not entirely true,” says Leon, comparing them to crabs or lobsters which are the definition of bottom feeders. “Tilapia are opportunistic and omnivorous, so they can eat a vegetarian diet, they can also prey on insects and things like that, so they eat what’s available.”

Scientists on the island are studying tilapia because it’s one of the few fish species that can transition from fresh water to salt water in a period of six hours. “What they’re looking at is the tilapia’s endocrine system, how it produces hormones and how it can change the physiology of its body to be able to survive that change in salinity,” says Leon. “By understanding that, they can make applications to the human endocrine system.” 

Host of hammerheads

Worried my son may have gotten lost in all the scientific terminology, I look over and find he’s absorbing the information better than I expected, and he’s especially excited by where Leon is taking us to next—the hammerhead shark tank. The tank looks more like a shallow waterway, with parts of it divided into very large pens. We walk out onto one of the bridges overlooking the hammerhead sharks in the clear water below, and we see many of them swimming calmly. Kaneohe Bay is known as a breeding ground for hammerhead sharks, and many of the sharks were pups in the waters surrounding Moku o Loe when the researchers brought them to these enclosures, and, Leon says, will be released at a later point in time. In many ways, this is very similar to their natural habitat. 

“Sharks have been around for 350 million years, so you’d think that the head shape [of the hammerhead shark] would be somewhat of a disadvantage, because their eyes are all the way on the ends,” Leon continues, explaining that the ampullae of Lorenzini, the shark’s electromagnetic sensory organ, located on their snout is what they use to find their food. “I’m pretty sure that all sharks have this. However, with the hammerhead, they’re able to spread that out on a much larger plane, and so they can cruise the seafloor with their head much like a minesweeper, and can detect some of the most minute electric signals.”

Touch pool for the senses

Our next stop is to a large touch pool nearby, filled with feather-duster worms, tiger cowry, urchins and sea cucumbers, and the adults look just as excited as my kid. Leon points out the feather-duster worms inside the pool and instructs us to touch them. They look soft, swaying gracefully in the water, and they’re long, just like a feather duster. “Whoa!” people shout out in surprise after they touch them. What was there has now disappeared in a flash. “So these are actually related to earthworms,” Leon begins. “Inside that leathery casing is a worm, and what you’re seeing are its feeding appendages, that plumage. Just like an earthworm, if you touch it, it will contract itself, and that’s exactly what these are doing.” After making our rounds, touching, or choosing not to touch, the many living things within the pool, my son whispers to me that he now wants a sea cucumber as a pet before Leon moves us along.  

History of Moku o Loe

We are headed back to the cove, when we see what Leon describes to be an old swimming hole, used by one of the island’s previous owners. Next to it is a deck, where there is a group of people having lunch, and, along our walking path, we pass a large, ship’s spotlight. Leon says it was used to light up the pool parties on-property long ago, something that sounds like a scene out of an F. Scott Fitzgerald book, and is actually not that far of a stretch from the island’s fascinating history. In the 1930s, Christian Holmes II, heir to the Fleischmann yeast fortune, inherited millions of dollars at a young age and bought the island in the 1930s from the Bishop Estate. He dredged out the lagoons, added lowlands and grew the island from its initial size of 12.4 acres to the 28 acres it is now. He had his own zoo with exotic animals of monkeys, chimpanzees, and a camel, zebra and pet elephant. He also dry-docked a four-masted schooner on the island and entertained celebrities aboard it, watching movies inside the ship that were decked out by his friends, the owners of Consolidated Theatres. The ship was also used in the John Wayne movie “Wake of the Red Witch,” and the actor is said to have waded away some afternoons in the island’s lagoon. When the Japanese attacked Hawai‘i in 1941, the atmosphere changed, says Leon, and Holmes turned the island over to the military for its use. Five years later, it was sold to Edwin Pauley, an oil magnate, who was the first person to establish a marine laboratory on the island in 1947. 

“After Edwin’s passing, it was put back on the market and [his widow] Barbara Pauley donated the funds to the University of Hawaii Foundation so that they could purchase the island outright,” continues Leon, rounding out our tour as we return back to the boat. “They are our great benefactors. They donated the money for the new and old laboratories, as well as the classrooms at the top of the hill, and they continue to fund the research to this day.”

Family Sunday Tours are typically held twice on the third Sunday of the month. $10 per adult, $5 per child, 12 years and under. Bring water and a hat.  Click here for more information about this tour and others.