If you live on the East Coast and have been to the beach during the last week it's likely you would've seen many bluebottles. An extended period of easterly winds has blown swarms of the creatures ashore and they have infested the line ups and gathered ankle-deep on the high tide mark. Here is some information on them, and also first aid tips for those unlucky enough to get stung.

See also Duncan MacFarlane's amazing close up shots of bluebottles.

Bluebottles (physalia utriculus) are a common feature along Australia's East Coast, mainly during the summer months. They are also occasionally found throughout the southern states of Australia, though far less often.

Commonly mistaken as jellyfish - who's smooth umbrella-shaped body propels itself forward by pumping or flapping - bluebottles have a gas-filled sac known as a 'sail' that allows it to float on the ocean's surface, its direction guided by prevailing winds, tides and currents. A stinging tentacle dangles below the sac that can reach up to a metre in length.

Bluebottles usually live in swarms across the tropical and subtropical regions of the South Pacific Ocean. When prolonged periods of easterly winds develop across these waters, bluebottles are driven westward into the coastal margins of Queensland and New South Wales. Here they will persist near the surf zone until local winds and currents drive them offshore.

When a bluebottle's tentacles come into contact with human skin, it releases a poison that creates a painful burning sensation. This often leaves a raised white welt on the skin with a prominent 'beading' effect.

Detached tentacles and dead bluebottles - including those stranded on shore - may remain potent several days after the death of the creature, especially in moist conditions.

If you or a friend are stung by a bluebottle, Surf Life Saving Australia recommends:

* Keep the patient at rest and under constant observation. * Do not allow rubbing of the sting area. * Pick off any remaining tentacles with fingers (a harmless prickling may be felt). * Rinse the stung area well with seawater to remove any invisible stinging cells. * Place the patient's stung area in hot water (no hotter than the rescuer can comfortably tolerate). * If the pain is unrelieved by the heat, or if hot water is not available, apply cold packs or wrapped ice.

If local pain is unrelieved by these treatments, or generalised pain develops, or the sting area is large (half of a limb or more), or if the patient appears to be suffering an allergic reaction to the sting, seek urgent medical help (dial 000 or 112 and get a surf lifesaver or lifeguard). //BEN MATSON