Sea life: Cushion stars

When I was a child, I thought all starfish looked like this.

Cushion star at Long Beach
Cushion star at Long Beach

Cushion stars are a kind of starfish, but instead of radiating limbs, they have legs that are so short that often only the tips are distinguishable from their bodies. They are extremely common in the rockpools along the Cape coastline, and we used to love picking them out among the algae and seaweed when we visited the beach. They are often very well camouflaged.

Cushion star on the Clan Stuart
Cushion star on the Clan Stuart

Like many starfish, cushion stars are sensitive to light, and in shallow water will often hide under a handy piece of sea lettuce. They are usually found on hard surfaces such as rocks, or the pipeline at Long Beach. They eat algae and anything else they can get hold of, including (yum) carrion and decaying organic matter in the ocean.

Cushion star on the Clan Stuart
Cushion star on the Clan Stuart

In the two photos above and the one just below you can see the greyish, roughly circular region just off centre on the top of the cushion star known as the sieve plate (or madreporite, if you want to be fancy). It’s made of pourous calcium carbonate. It is the entrance to the vascular system of the starfish: instead of blood and bones, sea stars draw water into their bodies and use this for a skeleton. It’s a handy adaptation that makes them pretty much incompressible, which is handy in an underwater environment. The water is also pumped to the tube feet underneath the creature, which enables it to move about.

The anus is roughly top and centre on the body of a starfish. You can just discern it in these images, most clearly on the one below (look for the tiny blue-grey circle with a black speck in the centre, to the left and above the sieve plate).

Cushion star at Long Beach
Cushion star at Long Beach

Both times I have visited Sodwana (October 2010 and April 2011) we have seen very large cushion stars. Here’s a close up of one we saw at Stringer. It was about the size of a birthday cake and its pentagonal shape was almost hidden by the bulge of the top of its body.

Close up of the giant cushion star
Close up of the giant cushion star

Handy hints: Sleeping on the beach

Clare is never one to miss an opportunity for a nap. She sat out one of the dives in Sodwana early one morning (she’s not a morning person and besides we’d had some hectic days prior to that). It was overcast but there was a glare from the sand, sea and clouds, and there was a slight breeze that made the air a little cold.

Clare chilling in Sodwana
Clare chilling in Sodwana

When we returned to the gazebo we found a jumbled pile of clothing, towels, sarongs, hats and neoprene. Somewhere under there was Clare, looking like a hobo and just waking from a nice little sleep.

Dive sites (Sodwana): Stringer – part 2

Close up of the giant cushion star
Close up of the giant cushion star

As Sophie and I started our ascent I saw a huge ribbontail ray swimming away from us on the sand. It was surgy and there was lots of sand in the water (as can be seen from the photos), so he disappeared fast.

Dive date: 19 April 2011

Air temperature: 23 degrees

Water temperature: 24 degrees

Maximum depth: 13.8 metres

Visibility: 10 metres

Dive duration: 55 minutes

Dive sites (Sodwana): Stringer

Stringer is made up of two separate, small outcrops separated by a sand strip about 20 metres wide. It’s a fish nursery, teeming with life, and we saw juveniles galore!

Dive date: 19 April 2011

Air temperature: 23 degrees

Water temperature: 24 degrees

Maximum depth: 13.8 metres

Visibility: 10 metres

Dive duration: 55 minutes

Handy hints: Keeping your feet clean on the beach

This post could equally well be titled How to spoil your little brother rotten, or How to be the best big sister in the world, or How to get a weight training workout without setting foot in a gym.

Kate carries Ollie across the beach in Sodwana
Kate carries Ollie across the beach in Sodwana

Here’s Kate, carrying her brother Ollie (who, at 15 years old is a keen rugby player – no welterweight) across the beach at Sodwana from the coffee shop to the gazebo. I think it was so his feet didn’t get sandy. Whatever the reason, I am impressed!

Surf launching

The vast majority of the best diving in the world lies beneath the ocean. I know there are many wonderful and exciting cave and quarry sites as well as inland lakes, but in South Africa we dive mostly in the ocean. Some of the launches are from sheltered harbour jetties and some are from sheltered launch sites in a cove or a bay. Many are however straight off the beach through the surf (such as in Sodwana, where these pictures were taken). On a calm flat sea this is very easy and safe but in rough conditions with huge swells it has a few risks.

The tractor pushes the boat into the water
The tractor pushes the boat into the water

The best operators and boat skippers will know the local conditions well and will rarely if ever launch if there are huge swells. So if the skipper is confident you should be safe.

The ladies climb in after pushing the boat out a bit
The ladies climb in after pushing the boat out a bit

A semi-ridgid inflatable dive boat is an extremely robust piece of equipment. They are well put together and can withstand a huge amount of punishment from the skipper and the ocean. They are also most often raced up the beach at high speed after every dive so they need to be tough. Most if not all will float despite being swamped with water, and many will stay afloat with more than 50% loss of air in the pontoons. There is most often a stainless steel keel strip under the boat and this takes most of the load as the boat is beached and trailored.

Everyone climbs on board
Everyone climbs on board

The risks

A dive boat filled with divers and their gear is stable and sits low in the water. The skipper will move people around to get the boat balanced and level and if all the divers have their feet in the foot straps on the deck it is then safe to race through the waves. Wave after wave can be punched with a boat and with the correct and well timed throttle control each wave can be crested gently without too much bone jarring. An inflatable boat can become almost vertical without capsizing but what it cannot do, nor can any other vessel for that matter, is handle waves from the side. A wave must be approached at as close to 90 degrees as possible. A huge swell can be approached at any angle, but a breaking or foamy wave must not.

Cresting a wave
Cresting a wave

Almost any boat will be rolled over by the motion of the wave. Unless you are on a keel boat (like a yacht), once over you are staying like that. A capsizing dive boat fills the air then the water with potentially lethal objects. Airborne weight belts, cylinders and cameras all have the potential for injury. Sandbanks are the most common cause of dive boats being rolled over as a sandbank stops the boat in its tracks allowing a wave to swing the boat on the anchored point (the motors) and the next wave will roll the boat over. The other cause of dive boat rollovers is a motor stalling in the middle of the launch. The sudden loss of power will render the boat poorly powered for wave hopping.

The skipper guides the boat through the breakers
The skipper guides the boat through the breakers

There are to my knowledge no practiced suggestions on how to stay safe. If the boat is going to go over the skipper will most likely shout “Jump!” and then do so quickly and try to get as far away from the boat as possible.

The most important rules:

  • Make sure you know that the skipper is experienced and aware of the local conditions.
  • Make sure the boat is in a well maintained state.
  • Make sure you are opposite your gear, it is secured correctly and add a little air to you BCD. This way it will float if tossed into the sea.

Don’t listen to the loud mouths on the boat that tell you to look at the land to avoid nausea. You won’t get sick while the boat is moving. WATCH the skipper, watch the sea and see what is coming at you. This way you can brace yourself for a wave, or any other unlikely event .

Despite the seemingly ease at which a boat rolls over I have done over a thousand dives from a rubber duck, launched through surf myself as a skipper and have never seen a dive boat go over. Many fishing boats, yes, but not dive boats. I think the industry and skippers in southern Africa and Mozambique are all well aware of the risks, loss of income and potential lawsuits so boats are generally well maintained and the skippers are experienced and capable. A skipper that gives divers scary launches does not last long in a dive resort. So sit back, hold on, feet in the straps and enjoy the ride.

Dive sites (Sodwana): Chain – part 2

Dive date: 19 April 2011

Air temperature: 22 degrees

Water temperature: 24 degrees

Maximum depth: 15.9 metres

Visibility: 10 metres

Dive duration: 59 minutes

Dive sites (Sodwana): Chain

Chain is so named because there is a ship’s anchor chain lying across the reef (hard to spot – I didn’t see it). This was my favourite dive in Sodwana this time around.

Dive date: 19 April 2011

Air temperature: 22 degrees

Water temperature: 24 degrees

Maximum depth: 15.9 metres

Visibility: 10 metres

Dive duration: 59 minutes

Dive sites (Sodwana): Four Buoy – part 2

Dive date: 18 April 2011

Air temperature: 22 degrees

Water temperature: 24 degrees

Maximum depth: 16.0 metres

Visibility: 10 metres

Dive duration: 59 minutes

Dive sites (Sodwana): Four Buoy

Dive date: 18 April 2011

Air temperature: 22 degrees

Water temperature: 24 degrees

Maximum depth: 16.0 metres

Visibility: 10 metres

Dive duration: 59 minutes