NOAA Teacher at Sea
John Sammons
Onboard NOAA Ship Albatross IV
July 25 – August 4, 2005
Mission: Ecosystem Survey
Geographic Region: Northeast U.S.
Date: July 31, 2005
Weather Data from the Bridge
Latitude: 41° 26’ N
Longitude: 66° 34’ W
Visibility: <1 mile
Wind direction: NW (306 degrees)
Wind speed: 7 knots
Sea wave height: 1’
Swell wave height: 1’
Sea water temperature: 15°C
Sea level pressure: 1023.3 millibars
Cloud cover: 90% fog, haze, dust
Question of the Day: Predict the mass and size of each scallop pictured above. Match them with the masses and lengths shown below.
Yesterday’s Answer: Answers may be different.
- flat body allows it to lay camouflaged on the bottom
- tail fin allows it to move through the water
- spiny back and tail protect it from predators
- long, slender body allows it to move faster through the water
- strong muscle allows it to close the shell to keep out predators
- strong arms allow it to pry open shells for food
Science and Technology Log
“Scallops are a family of bivalve mollusks; there are several hundred species of scallops, found in marine environments all over the world. Like most other bivalves, they consume phytoplankton and other small particles by filter-feeding. Unlike many bivalves (e.g., clams, which bury in the sediments), they live on the bottom surface, and can move by swimming. Atlantic sea scallops (Placopecten magellanicus, also known giant scallops or deep sea scallops) live only in the northwest Atlantic from Cape Hatteras to Newfoundland and the Gulf of St. Lawrence. Sea scallops usually spawn in late summer or early fall, though spring spawning may also occur. After hatching, larvae stay in the water column for 4-6 weeks. At settlement, they attach to a hard object by means of byssal threads produced by a gland at the end of their foot.”
*Thanks to Dvora Hart, Northeast Fisheries Science Center, for supplying the scallop information.
On Sunday, I was able to operate the Conductivity, Temperature, and Depth instrument by myself. This instrument is lowered into the water at every third designated stations. Data is collected as the instrument descends to the bottom. This data includes salinity (saltiness), temperature, and depth of the water. This is important since various marine animals require ideal temperatures to survive. Today’s CTD went down to 80 meters (think 80 meter sticks deep) and recorded a temperature of about 5 °C. That ‘s cold!
Personal Log
Scallop Catch
The heavy dredge is ready for another timely tow,
Expect to catch the scallops, to the surface they will go.
Dropping to the bottom where its 80 meters deep,
Spending fifteen minutes dragging and bringing in the keep.
Then they’re sorted on the surface while hiding in their shell,
The aging/growth ridges on their outside’s what they tell.
