Jennifer Fry, July 22, 2009


NOAA Teacher at Sea
Jennifer Fry
Onboard NOAA Ship Miller Freeman (tracker)
July 14 – 29, 2009 

Mission: 2009 United States/Canada Pacific Hake Acoustic Survey
Geographical area of cruise: North Pacific Ocean from Monterey, CA to British Columbia, CA.
Date: July 22, 2009

Weather Data from the Bridge 
Wind speed: 13 knots
Wind direction: 003°from the north
Visibility: clear
Temperature: 13.6°C (dry bulb); 13.2°C (wet bulb)
Sea water temperature: 15.1°C
Wave height: 1-2 ft.
Swell direction: 325°
Swell height: 4-6 ft.

Science/Technology Log 

Today we did a fishing trawl off the coast of Oregon. First, the scientists used multiple acoustic frequencies of sound waves.  After analyzing the sonar data, the scientists felt confident that they would get a good sampling of hake. The chief scientist called the bridge to break our transect line (the planned east/west course) and requested that we trawl for fish.

Here is an acoustic image (2 frequencies) as seen on the scientist’s screen. The bottom wavy line is the seafloor, and the colored sections above are organisms located in the water column.

Here is an acoustic image (2 frequencies) as seen on the scientist’s screen. The bottom wavy line is the seafloor, and the colored sections above are organisms located in the water column.

The NOAA Corps officers directed operations from the trawl house while crew members worked to lower the net to the target depth.  The fishing trawl collected specimens for approximately 20 minutes. After that time, the crew members haul in the net. The scientists continue to record data on the trawl house.

The trawl net sits on the deck of the Miller Freeman and is ready to be weighed and measured.

The trawl net sits on the deck of the Miller Freeman and is ready to be weighed and measured.

Today’s total catch fit into 2 baskets, a “basket” is about the size of your laundry basket at home, approximately 25-35 kilos. Included in the sample were some very interesting fish:

  • Viper fish
  • Ctenophores or comb jellies
  • Larval stage Dover sole, lives at the sea bottom
  • Jelly fish, several varieties (*Note: Jelly fish are types of zooplankton, which means they are animals floating in the ocean.)
  • Hake, approx. 30 kilos

The scientists made quick work of weighing and identifying each species of fish and then began working with the hake. Each hake was individually measured for length and weighed.  The hake’s stomach and otolith were removed. These were carefully labeled and data imputed into the computer.  Scientists will later examine the contents of the stomach to determine what the hake are eating. The otolith (ear bone) goes through a process by which the ear bone is broken in half and then “burnt.” The burning procedure allows one to see the “age rings” much like how we age a tree with its rings.

Personal Log 

A view from the trawl house during a fishing trawl.

A view from the trawl house during a fishing trawl.

Everyone works so very hard to make the Hake Survey successful.  All hands on the ship do a specific job, from cook to engineer to captain of the ship.  It is evident that everyone takes their job seriously and is good at what they do. I feel very fortunate to be part of this very important scientific research project.

 

 

A viper fish

A viper fish

Did You Know? 
Bird facts: An albatross’ wing span can be 5 feet, which equals one very large sea bird. A shearwater is slimmer and smaller yet resembles an albatross.

Animals Seen Today 
Ctenophore, Jelly Fish, Dover sole, Hake, Humboldt squid, Fulmar, Albatross, Gull, and Shearwater.

Here is something interesting, a hake with two mouths discovered in the trawl net.

Here is something interesting, a hake with two mouths discovered in the trawl net.

A hake and its stomach contents, including krill, smaller hake and possibly an anchovy

A hake and its stomach contents, including krill, smaller hake and possibly an anchovy

Dover Sole, larval stage

Dover Sole, larval stage†

NOAA Oceanographer John Pohl and NOAA Fish Biologist Melanie Johnson discuss data about the fish collected.

NOAA Oceanographer John Pohl and NOAA Fish Biologist Melanie Johnson discuss data about the fish collected.

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