Sea anemones plentiful in Sunshine Coast rockpools

LEFT: decorated anemone, RIGHT: green anemone.

Last Wednesday I went searching for sea anemones on a rocky shoreline south of Coolum Beach, and found five different species in the rock pools there.

My first sighting was of a decorated anemone (Oulactis muscosa) in a sandy, wave-exposed pool, which is a typical microhabitat for this species.

This animal has greyish-white tentacles and a dark red section inside its oral disc, and gets its name from the way it decorates its margins with sand and pebbles in order to better camouflage itself.

This species can often appear almost entirely buried by sand, but I found one specimen in a calmer rock pool that allowed for the good view shown above.

Next up was a green anemone (Aulactinia veratra), and this proved to be a common and variable species at this location.

It was most frequently found deep inside crevices, including some narrow and shallow ones that barely held any water at low tide.

The colour of this creature was not always the vivid green shown in the photo here, and it was quite often a muddy brown hue instead.

Encountering the decorated and green anemones at the start of my search made my eyes grow accustomed to typical anemone shapes and hiding spots, so much so that seeing the next wildly atypical species came as quite a surprise: I suddenly realised that stretching out over the rocks and pools before me lay a vast colony of tiny anemones that I had read about in the Queensland Museum’s Wild Guide to Moreton Bay.

These creatures were green and grey in colour, and the ones that were exposed to the air had retracted their tentacles into compact little stubs.

MAIN: unidentified Anthopleura species, INSET: Anthopleura handi.

In the first edition of the museum’s Wild Guide, these animals were considered to be zoanthids, relatives of anemones and coral that are often found together in large aggregations.

The second edition in 2011 updated their ID to being an unidentified species of Anthopleura anemone, however, and no information beyond that seems to be available.

Their green body columns and unmarked grey oral discs and tentacles are quite different to the related anemones found elsewhere in the Indo-Pacific region, and it is possible that they are unique to South-east Queensland and Northern New South Wales.

There was a second species of Anthopleura that I found at this location as well, albeit in much smaller numbers. It is called Anthopleura handi, and it has white banding on its tentacles.

One Australian anemone ‘superstar’ that I had been hoping to locate in the rock pools was the waratah anemone (Actinia tenebrosa).

Being a brilliant red colour, I originally thought it would prove easier to spot than its more camouflaged relatives, but I found otherwise.

It turns out that I was initially looking for this species in the wrong microhabitat; it actually grows not in the cracks and crevices like the other anemones, but midway up on the boulders where the surf crashes on an incoming tide.

MAIN: anemone survey area, INSET: waratah anemones.

Unfortunately, as I was visiting during a low tide, all I could see were the blobby body columns that the tentacles are withdrawn into when exposed to the air. Once I knew where to look, however, I could see that it was a very numerous species, and I will remember this information should I visit again on a higher tide.

For those of you who are as fascinated by these beautiful animals as I am, the Queensland Museum has published a helpful paper on all the various anemones found in our local waters (minus the undescribed colonial one), available in a free PDF format here.