Mark Wolfgang: Fish Eggs, I Will Take Mine Over Easy; April 15th, 2017

NOAA Teacher at Sea

Mark Wolfgang

Aboard NOAA Ship Reuben Lasker

April 11 – April 22, 2017


Mission: Spring Coastal Pelagic Species (Anchovy/Sardine) Survey

Geographic Area of Cruise: Pacific Ocean

Date: April 14, 2017

Weather Data from the Bridge:

Lat: 35o 47.1’N         Long: 122o 58.8’ W

Temperature: 14.9oC (59oF)

Wind speed: 29 knots

Barometer:  1020.92 mbar

Conditions: Windy, blue skies with a few clouds, choppy seas

Scientific and Technology Log:

The research into the fish that live in this area of the Pacific Ocean investigates the entire life cycle.  The night trawls will usually catch adults or juveniles.  There are other techniques to collect eggs and larvae.  One of these techniques is a Continuous Underway Fish Egg Sampler (CUFES).

The Continuous Underway Fish Egg Sampler (CUFES)

There is an intake valve 3m under the surface of the water and it is collecting water (and anything living in it) all the time.  As the Reuben Lasker moves along a transect water is collected through this machine and filtered.  Every 30 minutes, the specimens that have been collected are removed, counted, and identified under the microscope.  The samples are then rinsed into small vials, preserved in formalin and are labeled and stored.  On this survey, they are looking for sardine, anchovy, jack mackerel, hake, and squid eggs.  The sample also has numerous copepods, but those are not counted and recorded.  So far, we have found mostly jack mackerel and squid eggs which are reflected in our catches during the night trawl.

A second technique involves nets dropped off the side of the ship.  The first is net called a

Deck hands and the chief scientist deploying the pairovet from the side station

pairovet.  A pairovet is a vertical plankton tow.  The net is dropped off the side of the ship
to a depth of 70 meters.  The net stays in place for 10 seconds and then are pulled back up.  The specimens collected are rinsed into containers.  One net’s collection is placed in formalin, a preservative, for later identification, while a second net’s collection is placed in ethanol for possible DNA analysis.  The other net is called a Bongo Net.  This net is an oblique tow and is dropped to a depth of 210 meters and is pulled in at an angle of 45o.  The contents are preserved for later identification and possible DNA testing.  The pairovet has a finer mesh to the net, so it collects smaller zooplankton and icthyoplankton.

The Bongo net being lowered into the waters off of Big Sur


The trawls on the night of the 12th had some Jack mackerels, some larger squid, a couple octopi, and a single sardine.  For the Jack mackerel and sardine, we recorded their length

Jack Mackerel

and mass.  We also took tissues for DNA analysis as well as the gonads for female sardines, anchovies, Jack mackerel, and Pacific mackerel.  These will be used for histology and fecundity studies.  Fecundity is the ability to produce an abundance of offspring or their fertility.  We remove a small, hard structure called the otolith.  The otolith is found in the inner ear and maybe used for balance.  The otolith can be used for aging the fish.  We had high winds on the 13th, so we were only able to one trawl.  Ironically, we watched “Finding Dory” while we waited for the bridge to say it was safe to let out the trawl nets.  We didn’t find her.

Personal Log:

It has been quite challenging changing my sleeping schedule.  Not only am I all screwed up with the 3 hour time difference from home, I am currently working the night trawls from 6 pm to 6 am, although the heavy work doesn’t begin until after sunset.  I was awake for 28 hours straight, but was able to get some sleep and relax some this afternoon.  I got a chance to call home and talk to my family.  It has been difficult being away from them and not getting a chance to talk, but I had that opportunity today.  For that I am thankful.  There were some plans to fly the drone when we arrived at the coast of Big Sur, California, but the winds were too high to do so.  I continue to be impressed with the scientists and crew.  I love watching the team work – it is quite impressive.  As we moved up the coast today, I took a few minutes to look around and soak it all in.  Big Sur was beautiful, the sky was clear with only a few clouds, and the water was a deep rich blue.  It was gorgeous.  I am so glad I took a moment to realize how lucky I am.

Big Sur, California


Did you know?

The Pacific Ocean is the biggest ocean in the world.  It contains 30% of the space in the earth and contributes half of the water to the world.  It is also the deepest ocean in world, counted at 3800 m.  I am currently traveling through the Northern Pacific Ocean.

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