Tag: CTD Device

NOAA Teacher at Sea
Heather Haberman
Onboard NOAA Ship Oregon II
July 5 — 17, 2011 

Mission: Groundfish Survey
Geographical Location: Northern Gulf of Mexico
Date: Thursday, July 07, 2011

Weather Data from  NOAA Ship Tracker
Air Temperature:  29.2 C      (84.6 F)
Water Temperature:  29.3 C    (84.7 F)
Relative Humidity:  72%
Wind Speed:  2.64 knots

Preface:  There is a lot of science going on aboard the Oregon II, so to eliminate information overload, each blog I post will focus on one scientific aspect of our mission.  By the end of the voyage you should have a good idea of the research that goes into keeping our oceans healthy.

In case you’re new to blogging, underlined words in the text are hyperlinked to sites with more specific information.

Science and Technology Log

Topic of the day:  Groundfish Surveying

To collect samples of marine life in the northern Gulf of Mexico, NOAA Ship  Oregon II is equipped with a 42-foot standard shrimp trawling net.  NOAA’s skilled fishermen deploy the net over the side of the ship at randomly selected SEAMAP (Southeast Area Monitoring and Assessment Program) stations using an outrigger.  The net is left in the water for 30 minutes as the boat travels at 2.5 to 3 knots (1 knot = 1.15 mph).

Bottom trawling is a good method for collecting a random sample of the biodiversity in the sea because it is nonselective and harvests everything in its path.  This is excellent for scientific studies but poses great problems for marine ecosystems when it is used in the commercial fishing industry.

One problem associated with bottom trawling is the amount of bycatch it produces.  The term bycatch refers to the “undesirable” fish, invertebrates, crustaceans, sea turtles, sharks and marine mammals that are accidentally brought up to the surface in the process of catching commercially desirable species such as shrimp, cod, sole and flounder.  At times bycatch can make up as much as 90% of a fisherman’s harvest.  To address this problem, NOAA engineers have designed two devices which help prevent many animals from becoming bycatch.

All sea turtles found in U.S. waters are listed under the Endangered Species Act and are under joint jurisdiction of NOAA Fisheries and the U.S. Fish and Wildlife Service.  In an effort to reduce the mortality rate of sea turtles, NOAA engineers have designed  Turtle Exclusion Devices (TED).  TEDs provide these air-breathing reptiles with a barred barrier which prevents them from going deep into the fishing net and guides them out of an “escape hatch” so they won’t drown.  TEDs have also proven to be useful in keeping sharks out of  bycatch.

Another device that was introduced to the commercial fishing industry is the Bycatch Reduction Device (BRD).  BRDs create an opening in a shrimp trawl net which allows fishes with fins, and other unintended species, to escape while the target species, such as shrimp, are directed towards the end of the capture net.

Once the trawl net is brought back on board the Oregon II, its contents are emptied onto the deck of the ship.  The catch is placed into baskets and each basket gets weighed for a total weight. The catch then goes to the “wet lab” for sorting.  If the yield is too large we randomly split the harvest up into a smaller subsample.

Each species is separated, counted, and logged into the computer system using their scientific names.  Once every species is identified, we measure, weigh, and sex the animals.  All of this data goes into the computer where it gets converted into an Access database spreadsheet.

When the Oregon II ends its surveying journey, NOAA’s IT (Information Technology) department will pull the surveying data off the ship’s computers.   The compiled data is given to one of the groundfish survey biologists so it can be checked for accuracy and consistency.  The reviewed data will then be given to NOAA statisticians who pull out the important information for SEAMAP (Southeast Area Monitoring and Assessment Program) and SEDAR (Southeast Data and Review)

SEAMAP and SEDAR councils publish the information.   State agencies then have the evidence they need to make informed decisions about policies and regulations regarding the fishing industry.  Isn’t science great!  Most people don’t realize the amount of time, labor, expertise and review that goes into the decisions that are made by regulatory agencies.

Personal Log

During our “welcome aboard” meeting I met the science team which consists of a Chief Scientist, four NOAA Fisheries Biologists, three volunteers, one college intern, one Teacher at Sea (me) and an Ornithologist (bird scientist).

I was assigned to work the day shift which runs from noon until midnight while the night shift crew works from midnight until noon.  This ship is operational 24 hours a day in order to collect as much information about the northern Gulf fisheries as possible.  The Oregon II costs around $10,000 per day to operate (salaries, supplies, equipment, etc.) so it’s important to run an efficient operation.

I am learning a lot about the importance of random sampling and confirming results to ensure accuracy.   Amy and Brittany taught me how to use the CTD device (Conductivity, Temperature and Depth), set up plankton nets as well as how to sort, weigh, identify and sex our specimens.

The food has been great, the water is gorgeous and I love the ocean!  Stay tuned for the next blog post about some of the most important critters in the sea!  Any guesses?

Species seen (other than those collected)

Birds:  Least Tern, Royal Tern, Sandwich Tern, Laughing Gull, Neotropical Cormorant, Brown Pelican, Magnificent  Frigatebird

Go to http://www.wicbirds.net for more information about the various bird species seen on this trip.

Mammals: Common bottlenose dolphin