Saturday, July 21, 2012

A 'Reel' story, and adventures on the continental shelf

So, a few nights ago around 3am, I was finishing up some model work on my computer and went by the computer lab before bed... The winch operator asked me if my undergrad was awake, because apparently two Mahi had been sighted swimming around the ship.  I headed out to the deck, since I knew where the rods were stashed... A few minutes of waiting, and lo and behold, a pair of Mahi swim into the light of the ship's deck lights chasing squid.

One of the crew guys and I start casting, and I cast out to the edge of the light/shadow and start reeling in.  All of a sudden there's a pull on the line, and the bigger of the two fish (looked ~2 feet or so from up on the ship) starts jumping around like crazy.  I reel in as fast as I can, trying to keep up with it's jumping shenanigans, but while the other guy ran to get the net, the fish popped off the lure.  (argh).

We keep casting, in hopes that they're still hanging out... but I can't see them.  Then, crazily enough, the same fish hits my lure _again_.... and this time, I set the hook as hard as I can, and he starts fighting.  In what seemed like moments, I'm fighting the fish, reeling in as I can, when the handle of the reel just snaps off in my hand (!).   The reel is screaming away as the fish made for the hills, and I yell for help from the crew guy... who comes and finds that the handle has cleanly snapped off... but dashes of to grab a pair of vice grips... he proceeds to take apart the reel a bit so that he can get a clean grip on it, and manages to start reeling the fish in using the vice grip reel handle... (ridiculousness~!)

The rod was bending like crazy, and before long, he had it at the side of the ship.  I had a long net in my hands, but either couldn't see the fish in the shadow of the ship, or it kept diving under the ship, or it wasn't close enough to the surface.

And just when we thought we would get it on deck... the spool of the reel broke completely.  I grabbed the line to pull it in hand over hand, but as I was doing that, I felt the fish pop off the hook -_____-

Quite an adrenaline filled night, to say the least... the crew guy cast out at the smaller mahi that was still hanging around, and hooked it... but it too popped off the hook as I was trying to get the net again...

*sigh*  If we had landed that bigger fish, it would have been epic.  There's a lesson about fishing with crappy equipment in here somewhere... but ah well.  You win this round, mahi... we shall meet again hopefully...

In other news... after that night of infamy, we moved onto the continental shelf off the coast of Brazil.  Where once we were coring in 4000m of water, now we're dropping it in 20 m.   o_O

It's a completely different ballgame now.  The North Brazil Current, which conveys the plume waters to the northwest, is really strong here, sometimes moving as fast as 2.5 knots (nautical miles per hour).  This causes the instruments we deploy to 'kite' in the water, as they get dragged along.  This can be rather challenging to work in, as we typically need our instruments to be straight up and down.  The ship's crew has been doing a great job to help maneuver the ship to get the best samples.

Some photos of the work going on at these coastal sites:

Preparing to deploy one of the optical measurement instrument suites.  The instrument below is called the 'FRRF' which stands for Fast Repetition Rate Fluorometer. It measures fluoresence (which can detect pigments like chlorophyll) in the upper ocean as a means of measuring the amount of photosynthesis occurring.

Here Sarah is rinsing her sample canisters in advance of the CTD cast.  Sarah is a member of the Montoya group that measures the abundance and isotopic composition of suspended particles in the ocean.

And here's the deployment of the CTD.... notice the bright green water off to the side?  Last night it was brown!

Here's Brandon of the zooplankton team waiting for their surface net tow to come back... The continental shelf is far too shallow to use the MOCNESS, so they use smaller nets instead.

Here comes the net...

Now what about my group's work on the shelf?  In addition to the screaming fast current, we face another problem - the mud on this part of the shelf is very soft and soupy, which makes coring a challenge.  The way our corer works, is that the outer frame 'lands' on the sea floor and stops moving, allowing the center part of the corer to continue moving down, which triggers a release mechanism to close the lids and feet covering the core tubes.

We've been having a problem of the release mechanism not firing at all, even after hitting the bottom.  Once of our recent modifications has been to attach wood 2x4s to the frame, to give it more surface area to prevent the frame from sinking the same amount as the center spider.

Unfortunately, 6 tries in, we still haven't managed to get cores back on board yet.  We've come up with some new ideas to try and we'll give it a go again tomorrow when we're at the next station which happens to be right in the river mouth.

The multicorer with its new skids...

And now.... a sunset...

Til next time.....

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