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”.

image of a frogfish
Hiding in Coral

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.

image of a frogfish
Commersons Frogfish

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!

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.

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.

There be dragons here

Dragons, as most people understand them, are mythical creatures – huge fire breathing reptiles that can fly and sometimes even speak human language. That idea is nonsense but dragons do exist!

image of A Small Dragon Moray
A Small Dragon Moray

According to the Maui Ocean Center, there are 42 species of eel that can be found in Hawaii. According to everybody who knows their eels, the Dragon is the most exciting. I had a client recently who came here from Zurich, Switzerland hoping to see “the Holy Grail of eels.” Smart move on his part coming to Kauai because our local dive site, Koloa Landing, is famously popular for the great chance of finding one.

image of a dragon moray
Adult Dragon Moray Eel

Dragons can grow up to three feet long and are skilled predators of fish and octopus.  They have nostril tubes at the tip of their snout and a second pair above their eyes that look like horns.  The “horns”, together with a curved mouth and needle sharp teeth make the Dragon Moray appear ferocious.  In reality, if you keep your hands to yourself you are completely safe.  That is a lesson that we, as divers, should apply to all creatures on the reef – keep your hands to yourself.

A Regular Day

We were having a pretty regular day of scuba diving at Koloa Landing the other day.  In other words, it was spectacular!!!  Looking at the picture below you might think we were in a less interesting area of the reef.  You’d be wrong.  The rubble flats are home to some of the wildest creatures you will ever see.

image of a scuba diver underwater
Scuba Diver At 40 Feet

That picture was taken just seconds after finding a huge Commersons Frog Fish.  Easily the largest I’ve seen.  Commersons Frog Fish are ambush predators.  They sit patiently for long periods of time just waiting for some unsuspecting little fish to come swimming by.  Then, in just hundredths of a second, they open their giant mouth so fast that the victim gets sucked into the frog fish’s mouth and swallowed whole.  It happens so fast it’s like watching a magic trick: Now you see it, now you don’t.  It’s as if the fish simply blinks out of existence.

image of a Commersons Frogfish
Commersons Frogfish

Within minutes of finding the frog fish we had also found 2 Leaf Scorpionfish, a Devil Scorpionfish and 7 species of eel including a Dragon Moray.  So yeah, a regular day of scuba diving on Kauai’s coral reef.