Baffling Bluebottles

Physalia physalis which we have been using to ID the blueblottles found here does not exist here. Those are an animal that grows to 30 cm, a near full crest, and a large number of tentacles that can extend to 50 m and I am sure we will all agree that we have not seen anything that large in all of our bluebottle obs.

So what do we call ours? Well there seems to be four possible ID's for our ones.

Physalia utriculus (top left) has a single main fishing tentacle, a float with a high crest in the middle half of the float and long, cylindrical, tapering, posterior extension (right hand side). They can also have a bloated float.

Crested Bluebottle - Physalia sp1 (full crest) (top right) has one single main fishing tentacle, and a prominent crest along the full length of the float which does not stand up high like the Physalia utriculus crest, instead it shows more as "joins" as seen in the sample photo.

Barrel Bluebottle Physalia sp2 (no crest) (bottom left) has a single main fishing tentacle and no crest. The float is also smooth without any "joins" but you must turn the float to make sure that the "join" was not sand down.

Irukanji Bluebottle - Physalia sp3 (multi-tentacled) (bottom right) which has multiple main fishing tentacles. These are the long ones and we can see in the photo that there are at least 2 long ones.

The crest is the main thing to look at as what it is will eliminate most of the other species. Next would be the number of main fishing lines although it is really obvious when there is more than one.

Further Reading
This Obs with lots of korero
Flag for Physalia Genus
Photographing Bluebottles
Bluebottle Guide - Coming Soon

Posted by tangatawhenua tangatawhenua, February 22, 2019 04:51

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