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I live 80m above sea level I'm fine. We've had three massive rain storms in as many days. And yes I can swim. Lived on a boat off ...

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Impurest's Guide to Animals #104 - Green Surf Anenome

After the deluge comes the frost, as icy fingers wrap around the throat of this fair island nation. I’m certain though that the cold is a deterrent to the ariel menace known as the African Crowned Eagle which dive-bombed last week’s issue. If that wasn’t enough to keep it away perhaps the weeks tidal predator will make it thinks twice. Hope you guys enjoy.

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Issue #104 – Green Surf Anemone

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Kingdom – Animalia

Phylum – Cnidara

Class – Anthozoa

Order – Actiniaria

Family – Actiniidae

Genus – Anthopleura

Species – xanthogrammica

Related Species – The Green Surf Anemone is one of many species found in the genus Anthopleura (not to be confused with the fossil millipede genus Arthtopleura) (1)

Range - Green Surf Anemones live in tidal water ranging from Alaska in the north, all the way down the American west coast to Panama in the south

The Green Meanie

The Green Surf Anemone is a relatively large tidal anemone, with a maximum stalk height of 18cm, and a column width of 30cm. The oral disc is flat, and surrounded by feeding tentacles which form a feeding crown which grows to a width of 25cm. While mostly sessile the anemone can move to find new feeding pastures, or to avoid desiccation at low tide, but generally the animal withdraws its tentacle crown into the oral cavity until it is once again fully submerged in water.

The green colouration of the anemone’s tentacle crown comes from symbiotic photosynthetic bacteria living in the anemone’s gut (2), and provide their host with energy in return for a safe and sturdy platform on the tide battered shores. Despite this, the Green Surf Anemone is also a deadly predator, using the stinging cells in its tentacles to capture small fish, crustaceans and molluscs, with the anemone’s venom able to dissolve even the toughest of shells. On occasion the Green Surf Anemone will feed on larger prey, with reports of them feeding on young sea-birds, although it is unknown if the birds were dead before capture, or if the anemone killed them itself (3).

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Green Surf Anemones reproduce through sexual reproduction by releasing sperm or eggs into the ocean current, with fertilisation occurring in the open ocean. Once fertilised the larvae will drift with plankton until it gets too heavy and falls to the sea bed. From there the anemone heads to the coast, before anchoring itself to an unclaimed rock to start its sedentary adult life.

Nature’s Most Wanted #4 – White Spotted Jellyfish

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The White Spotted Jellyfish (Phyllorhiza punctata) is a large jellyfish, with stubby tentacles, recognisable by the white spots that are spread across its bell. Like most jellyfish it is little more than a passive drifter, often travelling in huge swarms with the currents. Within its native range off the shores of the Philippines, Indonesia and Australia numbers are controlled by a range of predators that feed on the larval polyp stage, but no such control occurs in its invasive range on both the Atlantic and Pacific Coasts of the Continental United States and Mexico, as well as Pacific island chains such as Hawaii.

Despite having a relatively mild venom, the White Spotted Jellyfish is still a deadly predator, and large numbers rapidly deplete local fish stocks, and are particularly detrimental to the Caribbean Sea shrimp fishing industry. In the Gulf of Mexico it has been calculated that in the winter of the year 2000, that the jellyfish were clearing almost 100% of all the fish, shrimp and crab eggs being laid by commercially valuable species (4).

The real mystery involving the jellyfish is how they arrived in American waters. While dispersal by ocean currents is possible, the sudden explosion of adult jellyfish makes this theory unlikely. The answer can potentially be found in the way the jellyfish breeds, with both the sedentary polyp form and the adult breeding, albeit in different ways. Whilst the adult breeds via sexual reproduction, the polyps clone themselves through a-sexual reproduction, with each of these clones able to make more copies before it matures into a free swimming sexual medusa. As such a single polyp stuck to the bottom of a boat in the western Pacific could, in theory, create a swarm of adult jellyfish as the boat stops in a port on the other side of the ocean.

Bibliography

1 - www.arkive.org

2 - Encyclopedia of Life. 2010. “Anthopleura xanthogrammica” (on-line), EOL.org. Accessed May 10, 2010

3 - http://www.marineornithology.org/PDF/42_1/42_1_1-2.pdf

4 - http://www.issg.org/database/species/impact_info.asp?si=992&fr=1&sts=&lang=EN

Picture References

1 - https://upload.wikimedia.org/wikipedia/commons/a/a9/Anthopleura_xanthogrammica_1.jpg

2 - http://i.dailymail.co.uk/i/pix/2014/05/15/article-0-1DDD518800000578-998_634x475.jpg

3 - https://upload.wikimedia.org/wikipedia/commons/2/27/Phyllorhiza_punctata_(White-spotted_jellyfish)_edit.jpg

Between sneaky sea anemones and destructive jellyfish it looks like a sting operation is being carries out. Next week we celebrate Australia Day… But until then critic, comment and suggest future issues as well as making sure you check past issues in Impurest’s Bestiary.

Many Thanks

Impurest Cheese

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