Friday, 16 May 2014

Barred Mudskippers

The most common mudskipper in north east Queensland is the barred mudskipper (Periophthalmus argentilineatus), named after the vertical silver bars on their sides.  They are usually a fairly unassuming fish from 5-10 cm long.

Periophthalmus argentilineatus, typical appearance

When they get riled up by the sight of a rival, they suddenly get colourful.

Periophthalmus argentilineatus threat display

Another thing that gets mudskippers going is food.  A shrimp was startled and flicked out of its pool and on top the muddy bank and was instantly pursued by a small mudskipper.  Each time the shrimp flicked its tail, it flew tens of centimetres and each time the mudskipper kept pace, catching up with the shrimp after a few seconds of agile persuit.  Think of that, a fish chasing erratically moving prey at high speed and accuracy across land.  It says that mudskippers have sophisticated vision and can move with precision even when leaping across the ground using their tails.  The exhausted shrimp can be seen lying on its side on the ground just in front of the close mudskipper.  It is at least half as long as the mudskipper and I wondered how the mudskipper would be able to eat it.  Other mudskippers were coming in by this stage, triggering threat displays from mudskipper number one.  Faced with a bigger mudskipper, it picked up the shrimp in its mouth and bounded away.

Periophthalmus argentilineatus with a captured shrimp


At night, mudskippers sleep in the open or in a the mouth of a crab hole.  Even when gently touched, they remain fast asleep.  As the tide often comes in at night, it leaves me wondering what they do.  The cannot stay put as predatory fish abound.

Periophthalmus argentilineatus sleeping

2 comments:

  1. The last two photos are P. gracilis.
    They stay put at night probably not because they sleep, but because they're stunned by your torchlight :-)

    In fact, they also feed at night.

    GP

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