NOAA Teacher at Sea
Leanne Manley
Onboard NOAA Ship Delaware II
March 24 – 31, 2005
Mission: Atlantic Mackerel and Herring Survey
Geographical Area: New Jersey
Date: March 24, 2005
Weather Data
Latitude: 40° N
Longitude: 72° W
SOG (speed over ground – boat): 10.8 knots
Speed log (speed of boat through water): 10.2 knots
COG (course over ground – boat): 241?
Furuno3 (3 meters deep) temp.: 2.4? C
Air temp.: 3.7? C
TSG (thermosalinograph) conductivity: 29
TSG Salinity: 31.4 ppt. (3.1%)
Fluorescence value (phytoplankton): 253 µg/L
Swells: 2- 3 feet (varies)
Science and Technology Log
This is my first shift. I’ve been told that most boats work a 6 hour on and 6 hour off shift cycle. This particular cruise, on board the 147’ DELAWARE II, we are pulling 12 hour shift cycles. I awoke at 0500 hours (10 Greenwich Standard time), gathered my gear, ate breakfast and then started interviewing crew members.
Last night (or early this morning) while I was off duty the night crew calibrated the Simrad 500 (echosounder – fish finder sonar). This sonar device is the standard device used by NOAA to do fish population counts. The basic objective of this cruise is to do acoustical fish surveys off the New Jersey continental shelf. We will transect the area of study going from shallow to deeper areas of the shelf.
Mike Jech is the chief scientist. He explained the meaning for the abbreviations on the data display screen. The probes that acquire this data are located on the hull of the DELAWARE II. They record a vast array of quantitative measurements. I included the ones in my log that apply to this cruise.
Eventually, we will deploy a CTD (conductivity, temperature and depth) sensor at the beginning and at the end of every transect. The abiotic datum it will provide is very important in order to accurately survey the fish.
Rob Gamble, contracting scientist with Mike, assists in handling the technology involved with the fish survey. He helps setup and run the Simrad equipment and the limnoterra, which is a magnetic fish measuring board. He also assists in the use of the FSCS (a computer program used to enter the fish survey data).
Dan Price is the acting executive officer on this cruise. He explained the transects that we will be doing off the coast of Southern New Jersey. An area of land off the coast was chosen to do population counts of Atlantic Mackerel and Herring. The transects are basically the ship’s course “transecting” the chosen area of study. Picture a large square with lines crossing back and forth (in a lawn mower pattern) across the square. We will transect the chosen squire/area about 8 times. Within this survey area, the fish finding sonar will be used to locate areas of schooling, or fish hot spots. Trawls and underwater video will be used to identify the fish found by the sonar.
Pete Langlois, acting chief Boatswain, is in charge of many things. One of his main areas of operation is handling and directing the releasing and retrieving of the trawling net. At 8:30am they (Mike, Pete, and Dan) released the trawl for a practice run. We will be at the area of study about 2 pm. At that time we will start the first transect. Mike Jech just stated that we have a leak in a hydraulic seal—the hydraulic system operates the trawl (among many other systems on this boat). The pictures I took show the net in the water, the leak was apparent when they started to retrieve the net. Most likely we have to enter a port to get the parts needed to repair the leak. For now, the Simrad will be used.
Personal Log
So far today has consisted of interviewing, writing log entries, taking Dramamine and staying hydrated. They have an exercise bike on this ship and it’s a nice reprieve for me! Since my students are on spring break, most are not available for e mail communication. I will show them my pictures when I return and highlight the objectives and methodology of this cruise. On only the first day I’ve learned a great deal about the equipment and methods used on this cruise.
