Tuesday, April 21, 2015

Marine Science @ Otago - Oarfish

An Oarfish was found washed up in the Otago Harbour on 17th April 2015.  This specimen was 3 metres long.  They are known to grow to more than 11 metres in length!

There are thought to be only two species of Oarfish and this is the southern one, Regalecus glesne.  There are periodic strandings round New Zealand, but mainly in the Cook Strait region between our two islands.  It is an oceanic fish, so that is probably because of the ocean currents that are funnelled between our two main islands and then get caught in shallow bays or sandbanks.  

However, It is pretty rare to find an Oarfish washed up in our area, and especially such a good specimen.  The Otago Museum had about 5 reports of Oarfish found on local beaches from the last 150 years.  Since our story went out, I've had two further reports.  One was stranded in almost the same spot in 1998, and one was reported on a beach further south in 2011.

They are often found after storms or earthquakes, which has given them a bit of a reputation as harbingers of doom!  This specimen was stranded after some very stormy weather.
Little is known about the Oarfish.  When this was dissected, its stomach was full of nyctiphanes (krill).  Other specimens have also been found stuffed full of krill.  They are a deep water ocean fish.  They have been some caught on video in recent years and they have been observed swimming vertically with their pectoral fins out to the side, which is how they get their name "Oarfish". 

Tyson Roberts wrote a book on Oarfish in 2012 and he suggested that Oarfish "self-amputate"  their tails.  This is his theory based on finding specimens that have obviously healed up after losing their tails.   It has been suggested by others that this might be caused by injuries or attacks by other creatures.  Perhaps they shed parts of their tails as a defence mechanism - like skinks and lizards - to help them escape.  As long as the injury is not too bad it may heal and grow back.  But who knows what goes on in the deep ocean and the lives of these amazing fish!

1 comment:

  1. More species are dying of natural and artificial disaster.Biodiversity requires a better understanding of animals and the development of biology