Hey aloha everyone!
Are you guys ready for an adventure?
Today we're gonna go explore a coral reef ecosystem. Let's go.
[Slack key guitar music]
Hi, I'm Michael, aquarist and teacher at Mokupāpapa Discovery Center located here in Hilo.
I grew up in these waters swimming, fishing, and diving,
and today I'd like to take you on an adventure to go explore a Hawaiian coral reef.
Before we jump in, let's take a look at this map of the Hawaiian islands.
We're here in Hilo on Hawaiʻi Island.
About 70 percent of all coral reefs in the United States are here in the Hawaiian Archipelago.
As we zoom out, you can see the other main Hawaiian Islands.
But Hawaiʻi is much bigger than most of us know.
Most coral reefs are located in the older Northwestern Hawaiian Islands
protected as Papahānaumokuākea Marine National Monument
and World Heritage Site.
That's the area in the light blue boundary.
We'll talk more about Papahānaumokuākea later, for now let's get going.
Corals create rich ecosystems.
The reefs provide both habitat and feeding grounds that attract many different species.
A healthy reef is full of life, often hidden at the first glance.
Help me find some of the animals that make their home here.
As we find things, I'll let you know the Hawaiian name followed by the English name.
Some small marine organisms don't have known Hawaiian names.
Here is a school of māʻiʻiʻi or brown surgeonfish feeding on limu or algae growing around the coral.
Look! We just surprised a Hawaiian white spotted toby, a type of small puffer fish.
There isn't a known Hawaiian name for this endemic fish.
Endemic means this species is only found in Hawaiʻi
There are some lauhau or four-spotted butterflyfish.
Butterflyfish actually are corallivores... or coral eaters
Not a bad day at the office don't you think?
Oh! I just got buzzed by an ʻāloʻiloʻi or Hawaiian dascyllus,
another endemic fish to Hawaiʻi.
They feed on plankton in the water column and shelter in branching corals.
Come over here.
Can you spot the loli or sea cucumber trying to camouflage in the sand?
That was a trick question. There are actually two loli.
Do you see the second one?
Loli are important ocean cleaners.
They eat huge quantities of detritus mixed in the sandy floor.
Oh here's another easy one to miss.
Check out this ‘ina kea, a rock boring sea urchin.
They use their spines to scrape limu off the rocks for food,
and can actually dig channels and holes in the rock.
They are important bio-eroders.
And here are some wana - a blue black urchin.
The long spines are painful if they break off into your skin,
but it's the secondary needle-like spines that carry the venom.
And here's a great example of another wana - the banded urchin.
You can see the shorter secondary spines better with this one.
Look there! This is the hāwaʻe maoli or collector urchin.
These urchins collect bits of algae, shells, and other material on their spines,
possibly to camouflage themselves or carry some snacks for later.
And finishing the urchin parade,
here we have a pūnohu or the red pencil urchin.
On other Hawaiian Islands it is also called the hāʻukeʻuke ʻula ʻula.
All of these urchins we've seen help clean the reef by feeding on algae and debris.
Swimming through here, you get a sense of how complex the reef habitat really is.
You have to pay attention if you want to see some of the coolest organisms on the reef.
This empty sea snail shell is actually home to the unauna or hermit crab.
They are important scavengers on the reef.
Did you notice those kio or Christmas tree worms?
The spiral fans you see are how they feed and breathe.
The body of the worm is safe in the tube built into the coral.
It can instantly draw the fans into the tube and block the opening.
Those grooves in the coral are actually burrows created by a never-seen snapping shrimp
called the petroglyph shrimp. The shrimp actually farms limu in the channels they carve out.
Let's check the reef edge where there's a little more water movement from the waves.
[gurgling sound of water]
Here's a surprise! Can you see the little marine slug?
This is an imperial nudibranch.
These are predators who hunt sponges, worms, sea slugs, and more.
The two purple tentacles on the right are sensory rhinophores.
The mass waving on the left are actually their gills.
Here's one more hidden picture game for you.
Can you spot the fish?
There’s an ‘ulae or lizardfish camouflaged in the rocks.
They'll stay motionless until a fish gets too close
and then they quickly strike with their needle-like teeth
and swallow them whole.
I thought that was the last surprise,
but check out this puhi or zebra moray eel.
I see the body,
let's see if we can find the head.
Ah, there it is!
Believe it or not, the zebra morays eat crustaceans,
crushing them with small blunt teeth and swallow them whole.
The small waves also carry in a lot of food.
The reef edge is a great place to see bigger fishes.
There’s a big school of pākuʻikuʻi or Achilles tang and māikoiko or whitebar surgeonfish.
Even though they are different species they are all surgeonfish and often school together.
Hey! Can you see that uhu or parrotfish feeding below?
Its color sure helps it blend in.
Hey, look over there!
A school of ʻōmilu or bluefin trevally.
I wonder if they are attracted to this huge school of juvenile fish at the surface?
Do you notice how the juvenile fish blend in with the wave foam and bubbles?
Wow! It's a honu or green sea turtle.
It's important to stay at least 15 feet away from honu
so they can help take care of the reef by feeding on algae that can overgrow the coral.
We've seen some of the animals that make their home here,
but did you know that coral itself is alive?
Come and look more closely at this pōhaku puna or mound coral.
Coral reefs are actually a colony of tiny animals called coral polyps living side by side.
In most cases the polyps are so small we can barely see them.
Do you see the small roundish bumps?
Each of those is home to an individual polyp.
There are thousands of polyps just in this one section of coral reef we're looking at.
Corals in Hawaiʻi grow an average of one to two centimeters per year.
As the coral colonies grow they can build huge reefs,
some forming over millions of years.
Now that we know corals are living animals,
I'm going to show you something really cool. Follow me.
Do you see how colorful the different coral species are?
These colors are actually created by microscopic algae called zooxanthellae.
They live within the tissues of the coral polyp animal.
The zooxanthellae take energy from the sun and turn it into food that they share with the polyps.
The coral polyps provide protection and some special nutrients to the zooxanthellae.
We call this a symbiotic relationship.
We humans depend on coral reefs as well.
NOAA estimates 500 million people depend on coral reefs worldwide.
Here in Hawaiʻi, reefs have provided us with food for thousands of years.
They help protect our shorelines from storms
and some are even used in anti-cancer and anti-viral medicines.
This is a coral skeleton.
If we look closely we can see the spaces or calyces where the coral polyps once lived.
The skeleton is made from the same calcium carbonate material
that other marine that animals use to make their shells.
You know the coral reefs are important,
now let's go look at ways that you can help protect them. Let's go!
[sound of wind blowing]
Coral polyps can get stressed or injured from too-warm ocean temperatures,
pollution, or when people touch or step on the reef.
When they are stressed, the polyps can expel the zooxanthellae from their bodies.
Without the algae to give their tissue color,
all we see are white calcium carbonate skeletons of the coral polyp.
We call this coral bleaching.
Here we can see some severely bleached rice coral.
At this point the coral polyps are still alive but much weaker and open to diseases and other problems.
If conditions improve, the coral can pull more zooxanthellae into its body and potentially recover.
Look at this cauliflower coral.
Notice that the left half is alive?
There is a bleached section,
and then the right half is bleached and covered with algae.
At this point all we are seeing is the skeleton of dead coral.
As the skeleton breaks down it helps to form sandy ocean floor and white sandy beaches.
All this time you've been relaxing on tiny pieces of dead coral
shells and other ocean life that contains calcium carbonate.
I'm headed back to shore.
Use what you've learned as we swim back.
How do you think the reef is doing?
Some coral reefs are so important they are given special protections.
Remember those older Northwestern Hawaiian Islands we saw on the map?
Papahānaumokuākea Marine National Monument protects 3.5 million acres of coral reef.
That's almost the same area as all the Hawaiian islands put together!
All of us can make a difference.
Be careful not to step on or touch living coral when you are swimming or fishing.
We can also reduce our carbon footprint to slow climate change
and the increasing ocean temperatures that are damaging coral reefs worldwide.
Research has shown that chemicals in some sunscreens
have harmful effects on the coral reef and other marine animals,
so be sure to cover up or use reef safe sunscreen.
I had fun learning and exploring with you today.
Please visit our website where we've put together activities
that will let you virtually explore reefs all across Papahānaumokuākea.
I hope you will join me in taking care of these special places.
Aloha.
[sound of waves hitting the shoreline]
[slack key guitar music]