Algalita Marine Research Blog

The Manta Trawl

Posted by: Katie Transue

Now, this data-collection device might look familiar to you…I’ll admit a little imagination is needed to see it but it was cleverly modeled after the largest species of rays, the Manta.  The Manta trawl will skim the ocean surface behind our vessel for several miles.  With it’s broad mouth, the trawl will capture particles as small as 1/3 of a millimeter in a fine mesh net.  The opening, which is 90cm wide and 30cm tall, is called an aperture. At the end of the aperture a .333mm mesh net is attached which terminates in a small collection sock called the cod end.
The Manta trawl has two angled wings that keep it floating on the ocean surface, as well as a
hood that directs surface splash back into the trawl.

While trawling, we hit a couple small patches of kelp that ended up filling the mouth of the trawl.  At this point, Charlie wanted to reel it in to make sure this obstruction wasn’t going to affect our sample.
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After getting the trawl back on board, the mesh net was washed into the cod end, which is then removed and strained.  This sample will be labeled and stored with a corresponding data sheet which includes the start and stop time and location of the trawl, start and stop numbers on the flow meter (the flow meter measures the distance trawled), time of day, and any other miscellaneous notable information about the trawl.

Stay tuned to see our sample contents!  -Katie

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Date Posted: August 1, 2011 @ 10:34 pm Comments (0) | Comment Shortcut

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