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Half a fish?

20 July 2014

The ocean sunfish really does look it is missing a middle section!

On my way back from Dun last week, Angus (Kilda Cruises) spotted a sunfish just a short distance from us.  Sometimes these creatures can be mistaken for sharks due to the dorsal fin that sticks out above the water but because it was so close its characteristic oval flattened shape was soon obvious. 

Small sunfish in Village Bay (Photo by Kilda Cruises)(Dorsal fin of the sunfish swimming within Village Bay) 

Our sunfish was small but as the heaviest bony fish in the world it is not uncommon for an adult to weigh 1000kg with some specimens weighing almost double this!  This coupled with their enormous size – on average 1.8 meters in length and 2.4 meters in height – means they are creatures of incredible proportions.   Because their favoured food items such as jellyfish, comb jellies and salps are not very nutritious they need to consume a vast amount to maintain their incredible bulk.    They do however also feed on sponges, small fish and eel larvae indicating that they forage at the surface, among weeds, on the seafloor and in deep water.

 Ocean sunfish (Photo by Kilda Cruises)

(Characteristic flattened shape obvious as the sunfish swims beneath the surface. Photo by Kilda Cruises)

The sunfish seemed to be basking at the surface of the water and Angus suggested this gave birds an opportunity to remove parasites from its skin.  Interesting fact, I thought!  With a little research it seems that these fish are prone to parasites with some 40 types on record.  Even the parasites have parasites…nature’s great, isn’t it!  In an attempt to rid themselves of these critters the sunfish have adapted their behavior and will breach out of the water, swim amongst kelpor sunbath on the surface as an ‘invite’ for fish or birds to dislodge their unwanted body guests.  Genius! 


Close up of a sunfish. A face that only a mother could love(A different sunfish basking at the surface with a face that only a mother could love! Photo by Kilda Cruises)

Once the sunfish went beneath the surface I was actually quite surprised by its speed even though it was a bit clumsy.  Most of my photographs ended up only showing a wave or a splash so many thanks to 'Angus @ Kilda Cruises' for allowing me to use his far superior images! 



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