Sign (left) and sponges (right) covered with feather stars, ascidians and hermit crabs

Update on the artificial reef: 4 months

The artificial reef, covered in sea lettuce
The artificial reef, covered in sea lettuce

Tony and I installed a small artificial reef on the sand at Long Beach on 20 November last year. We checked on it after 10 days, and again after nearly 4 weeks, and then did not visit it for an extended period of three months during which the visibility was very bad. Summer diving in False Bay is an exercise in patience!

This used to be a cream Woolworths plant pot
This used to be a cream Woolworths plant pot

We visited it again recently, but my camera battery had given out after too much diving and photography for one little camera for one day. We returned to the artificial reef on Saturday 19 March, after it had spent 119 days in the water (4 months).

Algae-encrusted PVC pipe disappearing into the sand
Algae-encrusted PVC pipe disappearing into the sand

The reef itself is now so covered with sea lettuce that we almost swam right past it. The PVC pipes are almost completely buried in the sand, and algae encrusts almost every surface except for the cable ties. Feather stars seem to have taken a particular liking to the sponges, which have retained their shape (if not their colour) remarkably well.

Sign (left) and sponges (right) covered with feather stars, ascidians and hermit crabs
Sign (left) and sponges (right) covered with feather stars, ascidians and hermit crabs

The reef is populated by lots of (shy) klipfish, many of whom take cover in the sea lettuce. One, however, was very friendly and I almost got left behind playing with him on the sand.

Friendly klipfish
Friendly klipfish
Klipfish and warty pleurobranch
Klipfish and warty pleurobranch

We found a very fat pipefish, and a whole bed of hermit crabs going about their business. At least one warty pleurobranch was in residence, sitting on the wooden box.

Fat pipefish on the reef
Fat pipefish on the reef
Mask box covered with algae
Mask box covered with algae

The sign requesting divers not to mess with the reef is completely encrusted with sea squirts of various sizes and descriptions – larger ones as well as the smaller colonical ascidians. It’s not legible any more!

Sign overgrown with ascidians
Sign overgrown with ascidians

We were amazed by how thoroughly the sea has taken over the various items we laid down four months ago. What was originally quite an ugly collection of pipes and other random objects has become a thriving little oasis on the sand. We purposely placed the artificial reef away from other rocky outcrops or detritus that housed copious marine life – out on the sand, we’d be able to see who passed by, and know that the reef was seeded from scratch and not from an adjacent underwater feature.

For a before and after comparison, I’d recommend you go and check out what the reef looked like in these prior posts:

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Clare

Lapsed mathematician, creator of order, formulator of hypotheses. Lover of the ocean, being outdoors, the bush, reading, photography, travelling (especially in Africa) and road trips.

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