Uncategorized | Garden Isle Divers

March 2, 2019April 12, 2019

Turtle Cleaning Station

close up image of a green sea turtle — Green Turtle

Hale O Honu is one of our favorite Kauai scuba diving sites. It is a very large and healthy coral reef that never fails to deliver a variety of exciting creatures. For most of the people we dive with, the favorite encounters are with the green turtles that are scattered abundantly across this section of reef.

As dive tour guides on Kauai, we know from experience that there are a few places where turtles like to hang out in large numbers – Hale O Honu is one of the busiest. There are a couple reasons why this seems to be the case. First is that the structure of the reef offers many places for the turtles to rest and be protected from predators and from the movement of the water. There are many depressions and overhangs where they can tuck themselves in and just relax.

A second reason is that the shape and depth of the reef is ideal for the growth of algae that turtles eat. A third reason – and the one that offers a lot of real interest to Hale O Honu – is that there is a major cleaning station here.

Turtle being cleaned

I have no idea how a cleaning station gets established in the first place but the animals involved clearly know how to make it work! For whatever reason, a section of reef that is not distinct in any way as far as we can tell becomes a place where turtles can simply show up and be cleaned. Most of the work is done by members of the Surgeonfish family. At Hale O Honu, this most often means Goldring Tangs and Brown Tangs. When a turtle wants to be cleaned, it will position itself above the reef and hang in the water with its fins drooping down. Fish will peck away at algae and parasites that grow on the turtle’s shell and skin. It’s a pretty cool arrangement where everyone wins – the turtle gets cleaned, the fish get fed and the scuba divers get to watch it all while having an up-close and personal turtle experience.

Come scuba dive kauai with Garden Isle Divers to have your own personal turtle encounter!

February 11, 2019April 12, 2019

A Whale Tale

A whale tale refers to a story that’s probably not true. This story is most assuredly true, though.

At up to 52 feet in length and 40 tons weight, it’s fair to say that Humpback whales are a big deal! More than in just the literal sense, though, whales really are a big deal. Tens of thousands of people per year pay to participate in Hawaiian whale watching excursions. On a nearly daily basis we are asked “Will we see any whales?” Between the months of November to March the answer is “Possibly.” We do see them on the surface regularly during the time they are here. More common, though, is to hear them while underwater. I spend the whole summer looking forward to the time they return and give us the amazing gift of their song.

Whale Song Recorded in Alaska

I like to keep my articles short so instead of writing a long post about the awesomeness of Humpback’s, I’m going to just share some cool facts about them.

There are over 100 recorded instances of Humpback whales defending members of other species from predator attacks.
When whales visit Hawaii, they don’t stay in any given area for more than a couple days. The way they move around is like a human visitor staying at ten different hotels on four islands over a couple week visit.
One reason it’s so important for boats to avoid close approaches to Humpback’s is because the whales don’t have a breathing reflex. If a boat were to strike one and knock it unconscious, it would suffocate and die.
A newborn Humpback is 12 to 15 feet long and will grow to about 30 feet long in the first year.
Humpback’s make a variety of sounds which appear to be social communication but only males sing. All the males in a particular group sing the same song which will undergo slight changes during each breeding season. When the whales return for the next season, they will all be singing the exact same song they were singing when they left at the end of the previous season.

August 28, 2018April 12, 2019

What? I Don’t See It

A few years ago there was an ad campaign that ran in several national level magazines.

image of a US Navy Seals recruiting ad — Navy Recruiting Ad

The ad was designed to promote recruitment to the US Navy Seals. It had a picture of a swamp and a caption underneath that said “Pictured from left to right . . .” I’m guessing that there really were soldiers hidden in the picture but the only thing I know for sure is I never could see them.

I think of that ad when I consider the unique characteristics of a Commersons Frogfish. Like a special forces soldier, the frogfish is aggressive and fearsome. Unlike a special forces soldier, though, only fish need to fear a frogfish.

The Waikiki Aquarium says on its frogfish page that “The frogfish is superbly adapted for its habit of ambushing prey.” The article explains some of the adaptations which make that statement true. First, the fish’s head is mostly mouth which enables it to swallow other fish as large as itself. Second, the fish’s small gill openings are tucked away behind the pectoral fins so that exhaled water will not reveal the fish’s presence to potential prey. Third, and this is the part that reminds me of the Navy recruiting ad, is that frogfish are so good at camouflage that they can be difficult to distinguish from the section of reef they are situated upon. They sometimes even have real algae growing on their skin!

image of a frogfish — Yellow Commersons Frogfish

When we scuba dive Kauai, we have the opportunity to view a number of creatures that are skilled at camouflage but frogfishes are among the most specialized of ambush predators; their camouflage is so effective that biologists call it “aggressive mimicry”.

As members of the same family as the deep sea Anglerfish, frogfish have a special spine that they can use as a sort of “fishing pole” to lure in a potential meal that needs to get just a little bit closer to be food. When an unlucky creature gets to within about the distance of the frogfish’s body length, the frogfish will open its cavernous mouth so quickly that the rapid suction will draw the prey into its mouth. This whole process takes place in just six to ten thousandths of a second, making this one of the fastest capture mechanisms in the animal kingdom.

We have several resident frogfish living at Koloa Landing – one of Kauai’s best dives. It is a virtual certainty that we pass by at least one of them on any given dive tour. The trick is to actually see one. For your best chance at coming face to face with a frogfish while scuba diving Kauai, book a tour with Garden Isle Divers today!

August 10, 2018April 12, 2019

Animal, Vegetable, Mineral?

My experience as a professional scuba tour guide on Kauai has been that people are most interested in seeing the colorful tropical fish that are found here. It’s common to come in from a dive and have someone ask a question like “What was that blue one with the yellow tail?” There have only been a couple times that I’ve had a client ask about coral. I’ve always assumed that’s because we can’t normally observe coral ‘behaviors’ like we can with fish.

image of Hawaiian Sergeant — Hawaiian Sergeant

That is easy enough to understand. After all, I’ve never had a coral try to chase me away from its egg deposit like a Hawaiian Sergeant will do.

Maybe more people would be interested in coral if they knew how amazing they really are. So, here is some cool stuff about corals.

image of coral polyp structure — coral structure

Coral is a fleshy animal that creates a stone ‘skeleton’. With most corals some of its food comes from single cell algae that lives in its cells. As Douglas Fenner says in his book Corals of Hawaii, this means that we can say coral is animal, vegetable and mineral. What other living organism is this true for?

When you see a head of coral, what you are actually looking at is hundreds to millions of individuals. Each of the individuals that makes up a particular head is known as a ‘polyp’. Because a head of coral is made up of many individuals, I think of coral heads as being like cities – some small and others larger.

image of mound coral colonies in kauai — Mound Coral Colonies

In the picture shown here, some of the Mound Corals can be thought of as being like Los Angeles or Chicago (without all the murder) while others would be more like Springfield or Grand Rapids.

An individual coral colony starts out as the result of spawning. Many corals release sperm and eggs into the water on a schedule that is known to marine biologists and frequently occurs in relation to a full moon. This means you can plan carefully and then witness, firsthand, this event. Once a colony is established, it will grow by a process of division which means that a given head of coral is a collection of genetically identical polyps. When a polyp divides, the new polyp will secrete limestone to create its skeleton. This process grows the substrate of a coral colony making the size of the coral head larger. This growth can add up to about a quarter inch per year. There is a particular Mound Coral at Koloa Landing that is roughly 15 feet in diameter which makes it thousands of years old. In other words, that particular head of coral is one of the oldest living animals on the planet.

The largest coral heads I see while scuba diving in Hawaii are Mound Corals. The polyps that make up this type of coral are about one sixteenth of an inch in diameter – slightly narrower than the lead of a standard pencil.

image of oval mushroom coral — Oval Mushroom Coral

The largest coral polyp in the world is Mushroom Coral which grows up to about 12 inches in diameter! To continue the cities comparison, a normal coral head is Tokyo and a Mushroom Coral is Godzilla.

These are just a few of the things I think are interesting about coral. If you like this then book a scuba dive tour with us today and I will share more with you. Even better, I will take you on an underwater adventure to explore the reefs of Kauai where you can see many different corals as well as all the beautiful tropical fish we have here.

March 19, 2018April 12, 2019

I Wanna See More of Those!

For as long as I’ve been a diver, I’ve been particularly excited to get to see a nudibranch. The first part of the name ‘nudibranch’ does mean “naked” but that has nothing to do with why they’re exciting to see!

The word “nudibranch” comes from Latin; “Nudi” means ‘naked’ and “branch” is ‘gills’. So, we are talking about an animal that, in most cases, has gills external to its body. Obviously, this is not normal animal kingdom type stuff!

image of a Gold Lace Nudibranch — Gold Lace Nudibranch

In the image of the Gold Lace nudibranch, notice the feathery looking stuff near the lower part of the body – those are gills. To put this in a totally inappropriate perspective, our president spends a lot of time talking out his tail while some nudibranchs spend their lives breathing through theirs. Does this mean they’d be good candidates for vice-president?

According to the World Registry of Marine Species there are currently at least 2,300 species of nudibranch that can be found throughout seas worldwide. While the greatest diversity can be seen on shallow tropical reefs, some have been discovered at depths exceeding 8,000 feet.

Now let’s get to the part about why I’m particularly excited when I get to see a nudibranch. As it says on Wikipedia “This group includes some of the most colorful creatures on earth.” As I say “These things are awesome!” It’s this colorful nature that makes them so fun to see. To put it simply, many are just plain spectacular.

If you’ve read some of my other posts then you might be starting to figure out that I’m pretty much a total nerd.

image of Orange Cup Coral — Orange Cup Coral

One sign of that fact is that I think it’s super cool how nudibranchs have a variety of ways to defend themselves. Since they are just slugs and couldn’t hope to outrun or outmaneuver larger predators, they’ve developed a variety of passive defenses instead. Some individuals have developed coloration patterns that mimic their primary food source. If the Cup Coral nudibranch was hanging

image of a Cup Coral Nudibranch — Cup Coral Nudibranch

around inside the Orange Cup Coral would you see it?

Other nudibranchs go the exact opposite route and have such intensely bright and contrasting color patterns that you couldn’t possibly miss seeing them. In these cases the bright colors are believed to signal to predators that the creature is either poisonous or intensely distasteful.

image of a Varicose Phyllidia — Varicose Phyllidia

And then, there are some – like the Blue Dragon – that can take stinging cells (nematocysts) from the animals they eat.

image of a Blue Dragon Nudibranch — Blue Dragon Nudibranch

This type of nudibranch is capable of eating these nematocysts and relocating them, through their digestive organs, along their bodies where they will then provide a defensive system for the nudibranch.

All of this is in sharp contrast to a creature like me who has primarily relied on an obnoxious personality and sarcasm as a form of keeping potential threats at a distance. In actual practice, this plan frequently backfires and actually creates enemies that didn’t previously exist. Again, our president. . .

I could go on listing interesting nudibranch facts but I think I’ll just post a few more pictures of some of the one’s we see while scuba diving on Kauai instead.