The great fish rescue

Anna Belcher (BAS)

A successful evening: 5 Pelagras (NOC’s drifting sediment traps) recovered and one fish life saved! As the third Pelagra was being lifted onto the ship, something seemed a little strange…one of the collection funnels was still filled with water…hmmm…wait, what’s that? A fish tail! The team gathered around, and sure enough there was a fish! Wedged in the funnel with its nose poking out the bottom. Word spread like wild fire on the ship and soon Larry the fish had quite an audience. Now just to get him out…

Fortunately fish rescuer Kev Saw was at hand, and after nudging Larry’s nose enough to let the water drain out, Kev grabbed Larry by the tail and released him from the sediment trap. Larry was naturally pretty excited and squirmed out of Kev’s hands and onto the deck of the ship. After a short blast of paparazzi photos, Kev scooped him up and tossed him over the side. Larry was free and happily swimming away from the ship with a great tale to tell his fish pals.

The Pelagra traps are actually designed to catch sinking particles, which carry carbon out of the surface ocean and into the deep.  They drift around with the currents at depths of between 50 and 1000 metres for about 3 days before popping back up to the surface.  The race is then on for the ship to locate them and recover them.  Thankfully the Pelagra traps have GPS beacons, lights and a very bright pink flag, all of which help us to find them again.  The ocean after all is a very big place!

The sinking material collected in the traps is analysed to figure out what kind of particles it contains (such as dead phytoplankton, zooplankton poo, aggregates) and how much carbon they are carrying.  This material is one of the key ways that the ocean stores carbon, helping reduce the effect of increasing carbon dioxide in the atmosphere.