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Päpaka/Tunnelling Mud Crab Austrohelice crassa

Endemic. Not assessed.

A frequently seen animal on the mudflats around the Estuary which is easily observed from the viewing platform on Dawick Street. As their name suggests they are enthusiastic tunnellers and can have a very complex burrow system which they diligently clean out at low tide. 

 

Scavengers by nature, they will eat not only carrion, worms and algae (seaweed) but also rummage through mud for morsels to eat.

 

As far as mud crabs go, they are a small species with a carapace (shell) growing to a maximum of 40mm. Eyes are on stalks, and these are reputed to see movement up to 40 metres distance but even so, they are a favourite prey of kōtare/kingfishers around the Estuary which hunt them from perched on tree debris or other structures that provide them with some elevation.

iNaturalist-Tunneling Mud Crab

titan acorn barn
Titan Acorn Barnacle  Megabalanus coccopama

What is believed to be the first record for this large and colourful barnacle found naturally in Aotearoa New Zealand was in November 2020. There are several other records however of them being attached to ships.

Their natural distribution is the Pacific coasts of South and Central America but is now being reported from other parts of the world, plus heading northward towards North America. It has been reported several times from Australia. 

As the individual found locally was attached to a cuttlefish bone it is thought to have originated from Australia where the nearest population of these familiar beach oddities are found.

Like numerous other species it is thought to be expanding its range as sea temperatures gradually warm.

Wikipedia-Titan Acorn Barnacle


Smithsonian Institute-Invasive data
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