Sea Anemones of Pulau Hantu

June 22, 2011

After attending the very enlightening and entertaining talk by sea anemone expert, Dr. Daphne Fautin at NUS this evening, I was inspired to put together a little photo presentation of sea anemone’s that can be found in the reefs around Pulau Hantu. Above: Singapore’s anemone fauna contains elements of both Pacific & Indian Oceans; this is probably due to Singapore’s location, and there are more species of anemone in Singapore than west coast of North America from Vancouver to Santa Barbara (around twice as many!) Above: A surreal photograph of four anemonefish in a anemone. The largest is the female, and the second largest is the male. If the female dies, the male (second largest) will become the female, and the rest will fill in the voids.

I’ve coupled the pictures with tweets from Ivan Kwan, who tweeted fervently during the little over an hour-long talk. Above: Removal of anemonefish leaves anemone vulnerable to predation by butterflyfish. Of the thousands of species of anemones known, only about 10 species are known to co-exist with anemonefish.

Anemonefish are NOT immune to being stung by anemones. So how do they avoid being stung? According to Dr. Fautin:
1 theory: mucus of anemonefish protects it from anemone’s sting.
2nd theory: anemonefish picks up anemone’s mucus as it rubs against tentacles, hence doesn’t trigger the stings. Evidence for both.

Anemonefish never occur without a host anemone, that is, anemonefish need an anemone in order to survive in the wild. Anemones of MOST host species seldom occur without fish symbionts but they can, hence the relationship is facultative.

Collecting anemones diminishes fish as well as anemone populations.

Collecting anemones diminishes fish as well as anemone populations. Anemonefish are not the only fish that live with anemones. Others include young of some damselfishes, such as convict fish (in temperate Canada).

Anemonefish can survive fine in captivity without host anemones, since there are no predators. Anemones have not been successfully spawned in captivity; all host anemones in aquaria are collected from the wild.

All sea anemones reproduce sexually, releasing eggs & sperm into the water; some are able to divide asexually. Some anemones can move along the seabed, leaving fragments that can grow into individual anemones!
To view more images of anemones, visit the Hantu Blog Gallery, or Wild Singapore.

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