Donna Knutson: The Absolutely Amazing Atlantic Sea Scallop, June 12, 2016

NOAA Teacher at Sea Donna Knutson
Aboard R/V Hugh R. Sharp
June 8 – June 24, 2016

2016 Mission: Atlantic Scallop/Benthic Habitat Survey
Geographical Area of Cruise: Northeastern U.S. Atlantic Coast
Date: June 12, 2016

Mission and Geographical Area: 

The University of Delaware’s ship, R/V Sharp, is on a NOAA mission to assess the abundance and age distribution of the Atlantic Sea Scallop along the Eastern U.S. coast from Mid Atlantic Bight to Georges Bank.  NOAA does this survey in accordance with Magnuson Stevens Act requirements.

Weather Data from the Bridge

Latitude:  40 26.375 N
Longitude:  68 19.266 W
Clouds: overcast
Visibility: 5-6 nautical miles
Wind: 21 knots at cruise speed of 4 knots
Wave Height: 4-6 occasional 8 ft.
Water Temperature:  56 °F
Air Temperature:  70 °F
Sea Level Pressure:  29.7 in of Hg
Water Depth: 100 m

Science and Technology Log

There are four types of scallops that are found around the United States.  The Sea Scallop is the largest and found primarily along the Eastern coast.  Therefore, it is called the Atlantic Sea Scallop.  Bay scallops are smaller, found closer to shore and are not usually harvested.  The Calico mollusk is the smallest and rare, and is primarily located around the coast of Florida.  The Icelandic scallop is also occasionally sighted around the United States.

The Atlantic Sea Scallop Placopecten magellanicus  is a deep sea bivalve mollusk.  It has a smooth shell and edges.  Young scallops have a pink/red color with darker stripes radiating outward form the hinge. The older sea scallop is more orange in coloration and may fade into white.  Photoreceptive eyes along their pale pink mantle, allow the scallop to sense changes in light allowing it to protect itself from possible dangers such as incoming predators.

Some mollusks are hermaphroditic meaning they have both sex organs in the same animal, but the Atlantic sea scallop has two distinct sexes.  It is impossible to tell what the sex of a scallop is from its outward appearance.  When looking inside at the gonads it is easy to detect.  The male gonads are creamy white and the female gonads are pink/red in color.

The female can reproduce after they are one-year-old, but four year olds release many more eggs.  The older scallop may emit one to two hundred seventy million eggs at one time.  Spawning occurs twice a year, once in the spring and another in the fall.  Males will release their sperm into the water where the eggs have been released, and then the fertilized egg sinks to the bottom of the ocean to develop in groupings called beds.

Adult scallops will filter feed on phytoplankton and microscopic zooplankton.  The immature larva are filter feeders as well, but can also absorb nutrients though their tissues.

Atlantic sea scallops play an important role in the ecosystem as they become food for other animals such as starfish, crabs, lobsters, snails, and fish such as cod, American plaice, wolfish, and winter flounder.

Sources:

Wikipedia, May 30, 2016

US Atlantic Sea Scallop, March 31, 2013

Personal Log

Leg III of the Atlantic Scallop/Benthic Habitat Survey started out a bit rough, bad weather came in from Hurricane Collin and caused a few delays.  The lead scientist Tasha O’Hara decided to push back the departure times in hope of gentler seas.

We set sail on Thursday June 12^, 2016 around 7 p.m. from NOAA’s Northeast Fisheries Science Center in Woods Hole.  The Sharp started the third leg of four on the scallop survey.  The last leg will end on June 24, 2016.  The survey team will use a camera to take pictures of the bottom called a HabCam, which stands for Habitat Mapping Camera, and also dredge the ocean bottom periodically for physically counting and measuring specimens.

I have been allowed to participate in the driving of the HabCam and also the sorting, measuring and recording of animals brought up from the dredges.  My blogging got a bit behind as I was trying to immerse myself in the new experiences when the sea sickness hit.

I did not get sick once on the last month long experience, but conditions here are a bit different.  The captain of the Sharp, James Warrington, explained the gyre (oceanic current pattern) is unique here.  We are in a cruising within circular gyre and with weather conditions forcing high waves into the flat bottomed boat, we are getting a lot of motion.  So, yes, I now know what sea sickness is like.  Today the wind has died down a bit so the waves are not as high, and I feel much better.  I have been placed on the midnight to noon crew so that has been an adjustment as well.  I’m sure you morning classes will agree I’m more active in the afternoon.  Not really a morning person. J

Everyone is so great to me here.  They were very considerate during my seasick time.  I actually have been sitting up on the bridge with Captain Jimmy.  I can see the horizon and feel more stable.  Otherwise we are below decks looking at computer screens for the HabCam or working on the back deck looking at the dredged creatures.

Today we are doing some back tracking to get a start on more dredging and that has allowed me to get this blog in.  I really wanted it to be sooner, but that’s the story.