Into the Deep - Diving the Great Blue Hole, Chain Wall and Half Moon Caye Wall

The winds have calmed and the sea is smoother, so we are clear to zip over to the Great Blue Hole this morning. As I mentioned in an earlier post, the Blue Hole is a flooded fresh water cave system formed through a few periods of glaciation. It is 124 m (407 ft) deep, 318 m (1,043 ft) across and at least 150,000 years old. It resides in the centre of the Lighthouse Reef Atoll - here's a cool photo from space courtesy of Wikipedia. You can see a tiny perfect circle in the middle just below the clouds. That's the Blue Hole. Science is neat!

We are not.

There are two points of ingress into the blue hole. Most boats approach from one to moor on the other. It's really quite tough to see that there is a giant flooded cave from water level. It looked pretty indistinguishable as we approached.

When I asked what there was to see, the answer was either “stalactites” or “not much”. It is more of a technical dive than nature safari. We begin with a bit of a swim from the boat to the north east break in the circular reef surrounding the hole. The next step is to descend down to about 5 metres (15 feet) to check everyone’s ears and equalization. Next it is over the ledge and slowly down to the first stalactite at 34 m (110 ft). The maximum depth we are aiming for is 40 m (130 ft). Due to the more technical nature of the dive, you're required to have Advanced Open Water (or equivalent) certification and a minimum of 24 dives prior to attempting the Blue Hole. I'm not sure if it was our boat's policy or government policy, but we were also required to remain with our two guides at all times.

Down we go!

Somehow we were slightly distracted and dropped to 42 m (138 ft) at one point...

Something interesting I learned is while my camera (Nikon AW130) can take photos until 30 metres (100 ft), after that, the pressure is too much for the spring in the button and/or the shutter to depress. But it can still take video! And also fortunately didn't leak or crack under the added pressure.

As we slowly ascended and came over the ledge or crest of the cenote, we started seeing some of the usual creatures in the reef and sand. We had lots of time to look around during our extended safety stops.

File clam

Small snail

A turnicate - type of bivalve

Brittle stars in a sponge

After the great blue yonder, we headed back to the boarders of Lighthouse Reef for a shallower dive on a site called Chain Wall. We didn’t have much luck with the dive there as strong currents made conditions tricky. We spotted a few things before heading back to the boat. It was weird to experience two different strong down currents; a warm jet of water coming from over the sand channels and a cold blast of water from over the reef. When you’re working hard to keep your buoyancy under control, you can go through a lot more air than usual so you have to keep an eye on your air supply. 

The Fisharts getting ready to go

Brittle star in orange sponge

I don't really know what this squishy pink dealy is but I thought it was cool. Probabily a turnicate?

A grouper getting a cleaning

We moved on to a different site that had less current and more visibility on a reef system called Half Moon Caye. Both Half Moon Caye and the Great Blue Hole are actually Natural Monuments in Belize. Half Moon Caye was actually the first marine natural monument in Central America. There are three endemic species on the island - the Red-footed Booby bird, the Island leaf-toed gecko, and the Allison's anole lizard. It's also an important nesting ground for the three local species of sea turtles - green, hawksbill and loggerhead. None of which we got to see because we had a slim chance of catching a water taxi from our boat to shore, but it was too rough and the taxi was already engaged. Poop.

Oh well. Plenty to see under the water anyways! We did our last two dives of the day on Half Moon Caye Wall. 

Garden eel

Moon jelly. Someone booped it on its bell. Boop!

Arrow crab - note his cool blue pincers and long stabby "nose"

Brittle star

A crowded tube sponge

French angelfish

A cave swim through. Very murky!

A derpfaced flounder. Technically a Peacock flounder, but look at his derp face!

Juvenile wrasse with orange bellies 

Sitting very still and staring carefully in the tiny holes and cracks of a one metre by one metre cement mooring block, we found a beautiful little (maybe one centimetre wide and five centimetres long) sailfin blenny. And a little ways down the block, there was a female sailfin blenny. They are quite skittish, so you have to wait patiently for them to poke out of their homes and even more still to see them flash their sails. Their eyeballs are also cool. They always look like a mad cartoon character.

Lady blenny

Searching for more tiny, delicate creatures, I noticed something zip past like an aquatic bubmle bee. Turned out to be this little guy, once it slowed down a bit.

Teeny little baby gray angelfish. He has blue pectoral fins!

Unarmed cryptic shrimp (which we have been calling grass shrimp)

The seas turned on us a little and things got slightly rough and windy, so we headed back across to Turneffe and a sheltered cove. Which means a bit of a bumpy ride over dinner and no night dive. Which also means drinking with dinner, so cheers!