David Madden: Engines, Dolphins, and Sharksuckers, July 24, 2019

NOAA Teacher at Sea

David Madden

Aboard NOAA Ship Pisces

July 15-29, 2019


Mission: South East Fishery-Independent Survey (SEFIS)

Geographic Area of Cruise: Atlantic Ocean, SE US continental shelf ranging from Cape Hatteras, NC (35°30’ N, 75°19’W) to St. Lucie Inlet, FL (27°00’N, 75°59’W)

On board off the coast of South Carolina – about 50 miles east of Charleston (32°50’ N, 78°55’ W) – after a slight change of plans last night due to the approaching tropical depression.

Date: July 24, 2019

Weather Data from the Bridge:
Latitude: 32°50’ N
Longitude: 78°55’ W
Wave Height: 3-4 feet
Wind Speed: 15 knots
Wind Direction: Out of the North
Visibility: 10 nm
Air Temperature: 24.6°C 
Barometric Pressure: 1011.8 mb
Sky: Cloudy

Sunset over the Atlantic Ocean
Sunset over the Atlantic Ocean
NOAA Pisces Full Track 7-20-19
This is a map from the other day outlining the path of the ship. The convoluted pattern is the product of dropping off and picking up 24 (6 x 4) fish traps per day, along with the challenges of navigating a 209 foot ship in concert with gulf stream currents and winds.



Science and Technology Log

Life and science continue aboard NOAA Ship Pisces.  It seems like the crew and engineers and scientists are in the groove.  I am now used to life at sea and the cycles and oddities it entails.  Today we had our first rain along with thunderstorms in the distance.  For a while we seemed to float in between four storms, one on the east, west, north, and south – rain and lightning in each direction, yet we remained dry.  This good thing did indeed come to an end as the distant curtains of rain closed in around us.  The storm didn’t last long, and soon gathering the fish traps resumed. 

Dave with red grouper
Processing fish: measuring length and weight of a red grouper, Epinephelus morio.
Fish Count for July 23, 2019
Yesterday’s fish count. Compare to other day’s catches: Tons of vermillion snapper, tomtate, and black sea bass. And one shark sucker (read on for more). Thank you, Zeb, for tallying them up for me. 


The highlight of yesterday (and tied for 1st place in “cool things so far”) was a tour of the engine room lead by First Assistant Engineer, Steve Clement.  This tour was amazing and mind-blowing.  We descended into the bowels of the ship to explore the engine rooms and its inner workings.  I think it rivals the Large Hadron Collider in complexity. 

I kept thinking, if Steve left me down here I would surely get lost and never be found.  Steve’s knowledge is uncanny – it reminded me of the study where the brains of London cab drivers were scanned and shown to have increased the size of their hippocampus.  (An increase to their memory center apparently allows them to better deal with the complexities of London’s tangled streets.)  And you’re probably thinking, well, running a massive ship with all its pipes and wires and hatches and inter-related, hopefully-always-functioning, machinery is even harder.  And you’re probably right!  This is why I was so astounded by Steve’s knowledge and command of this ship.  The tour was close-quartered, exceptionally loud, and very hot.  Steve stopped at times to give us an explanation of the part or area we were in; four diesel engines that power electric generators that in turn power the propeller and the entire ship.  The propeller shaft alone is probably 18 inches in diameter and can spin up to 130 rpm. (I think most of the time two engines is enough juice for the operation).  Within the maze of complexity below ship is a smooth running operation that allows the crew, scientists, and NOAA Corps officers to conduct their work in a most efficient manner. 

Dave and Steve and engines
First Assistant Engineer Steve Clement and TAS Dave Madden in the Engine Room

I know you’ve all been wondering about units in the marine world.  Turns out, students, units are your friend even out here on the high seas!  Here’s proof from the bridge, where you can find two or three posted unit conversion sheets.  Makes me happy.  So if you think that you can forget conversions and dimensional analysis after you’re finished with high school, guess again!

conversions
Posted unit conversion sheets

Speaking of conversions, let’s talk about knots.  Most likely the least-understood-most-commonly-used unit on earth.  And why is that?  I have no idea, but believe me, if I were world president, my first official action would be to move everyone and everything to the Metric System (SI). Immediately. Moving on. 

Back to knots, a unit used by folks in water and air.  A knot is a unit of speed defined as 1 nautical mile/hour.  So basically the same exact thing as mph or km/hr, except using an ever-so-slightly-different distance – nautical miles.  Nautical miles make sense, at least in their origin – the distance of one minute of longitude on a map (the distance between two latitude lines, also 1/60 of a degree).  This works well, seeing as the horizontal lines (latitude) are mostly the same distance apart.  I say mostly because it turns out the earth is not a perfect sphere and therefore not all lines are equidistant.  And you can’t use the distance between longitude lines because they are widest at the equator and taper to a point at the north and south pole.  One nautical mile = 1852 meters.  This is equal to 1.15 miles and therefore one knot = 1.15 miles/hour. 

This next part could double as a neato fact: the reason why this unit is called a “knot” is indeed fascinating.  Old-time mariners and sailors used to measure their speed by dropping a big old piece of wood off the back of the boat.  This wood was attached to some rope with knots in it, and the rope was spun around a big spool.  Once in the water the wood would act kind of like a water parachute, holding position while the rope was let out.  The measuring person could then count how many evenly spaced knots passed by in a given amount of time, thus calculating the vessel’s speed. 



Personal Log

The scientists on board have been incredibly helpful and patient.  Zeb is in charge of the cruise and this leg of the SEFIS expedition.  Brad, who handles the gear (see morning crew last post), is the fishiest guy I’ve ever met.  He seriously knows everything about fish!  Identification, behavior, habitats, and most importantly, how extract their otoliths.  He’s taught me a ton about the process and processing.  Both Zeb and Brad have spent a ton of time patiently and thoroughly answering my questions about fish, evolution, ecology, you name it.  Additionally, NOAA scientist Todd, who seeks to be heroic in all pictures (also a morning crew guy), is the expert on fish ecology.  He has been exceptionally patient and kind and helpful. 

The fish we’re primarily working with are in the perches: Perciformes.  These fish include most of your classic-looking fish.  Zeb says, “your fish-looking fish.”  Gotcha!  This includes pretty much all the fish we’re catching except sharks, eels, and other rare fish. 

For more on fish evolution here are two resources I use in class.  Fish knowledge and evolution: from Berkeley, A Fisheye View of the Tree of Life.

Fish Tree of Life Berkeley
Fish Tree of Life, from University of California-Berkeley

And check out Neil Shuban’s Your Inner Fish series.


General Updates:

  1. Plenty of exciting animals lately.  Here’s a picture of those spotted dolphins from the other day.
  2. The weather has been great, apart from yesterday’s storm.  Sunrises and sunsets have been glorious and the stars have been abundant. 
  3. We found a common octopus in the fish trap the other day.  The photo is from crew member Nick Tirikos.      
  4. I’m missing home and family. I can’t wait to see my wife and son. 
  5. That tropical depression fizzed out, thankfully. 
spotted dolphins
Spotted Dolphins
common octopus
Common Octopus (Photo by crewmember Nick Tirikos)


Neato Facts =

Yesterday we caught a shark sucker in the fish trap.  I was excited to see and feel their dorsal attachment sucker on top of their head. 

Hold on.  I just read more about these guys and turns out that sucking disc is their highly modified dorsal fin!  That is the most neato fact so far.  What better way to experience the power of this evolutionarily distinct fish than to stick it to your arm?!  The attachment mechanism felt like a rubber car tire that moved and sealed against my skin. (Brad calls them sneakerheads).

Shark sucker
Shark Sucker on Dave’s Arm

Consider all the possible biomimicry innovations for the shark sucker’s ability to clasp onto sharks and fish and turtles while underwater.  This grasp and release adaptation surely has many cool possible applications.  Here are a few: Inspiring New Adhesives.  Robotic Sticky Tech.   Shark Sucker biomimicry

I’d love to hear your questions and comments!