Donna Knutson: The Atlantic Sea Scallop – More Than Meets the Eye, June 21, 2016

NOAA Teacher at Sea Donna Knutson

 Aboard the Research Vessel 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 21, 2016

The Atlantic Sea Scallop – More Than Meets the Eye

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.

Science and Technology:

Latitude:  41 16.296 NIMG_3250 (2)better me

Longitude:  68 49.049 W

Clouds: overcast

Visibility: 5-6 nautical miles

Wind: 21.1 knots

Wave Height: 4-6 occasional 8

Water Temperature:  59 F

Air Temperature:  64 F

Sea Level Pressure:  29.9 in of Hg

Water Depth: 101 m

Science Blog:

Sea scallops are unique from clams, molluscs and other bivalves.  All of them are filter feeders, but the sea scallop filters out larger sized particles such as diatoms and large protozoans that are larger than 50 micrometers. Clams filter feed on smaller animals and particles that are too small for the scallop to retain and therefore flow right through their digestive system.

Older scallop found in a protected area.

Older scallop found in a protected area.

Dr. Scott Gallager is looking inside the stomachs of scallops.  His hypothesis is that microplastics are traveling down to the bottom of the ocean, and if they are, the scallop will siphon them into their stomach along with their food.

Microplastics are, as the name suggests, small pieces of plastic measured in micrometers.  They may enter the ocean as an object such as a plastic water bottle, but over time with the turbulence of the ocean and the sun’s ultraviolet radiation break down into smaller and smaller pieces.

Another way microplastics are entering the ocean is through the cleaning products we use.  Many shampoos, detergents and toothpastes have small beads of plastic in them to add friction which aid the products cleaning potential.  Untreated water, such as runoff, has the likelihood of flowing into the ocean bringing microplastics with it.

Small colorful scallops.

Small sea scallops.

If a sea scallop ingests microplastics the same size as its food, the scallop will not be getting the nutrients it requires.  Large quantities of micro plastics falling to the bottom of the ocean would obviously cause the health of scallops to deteriorate.

Another interesting story of the sea scallop is its “attachment” to the red hake.  It is not a   physical attachment.  There appears to be a sentimental attachment between the two even though that is obviously not possible.

The red hake is a fish that starts out its life as a small juvenile without any protection.  It finds a home and refuge inside a sea scallop shell.  The sea scallop almost befriends the little red hake and allows it to live behind its photoreceptive eyes, next to the mantle.

The fish curls its body into the same contour shape as the scallop.  The little fish can swim in at times of danger and the scallop will close its shells to protect them both.  After the threat has passed the scallop opens its shells and the little red hake can swim out.

Red hake did not make it in before closing time.

There seems to be some commensalism between the two.  Commensalism is the relationship between two different species where each live together without any one feeding off of the other.  They live in harmony with each other neither hurting the other.  It is not known whether the fish feeds on the scallops’ parasites or if they just coexist together.

It is clear something is happening between the two, because after the red hake grows and no longer fits inside the shell, the fish will still live next to the scallop.  It now will curl itself around the outside of the shell.  Looking at HabCam pictures, it appears to curl around a scallop even if the scallop is no longer alive.  Could it really be the same scallop it lived in as a minnow?

DSCN7843 (2)RED HAKE AND SCALLOP

Red hake curled around its scallop. Picture taken from the HabCam.

Red hake numbers increase in areas where there are larger, more mature, sea scallops present.  What connects two together?  Is there some chemical connection where the fish can identify the scallop it “grew up” with? 

Why is the red hake red?  The red hake is part of the cod family.  The other fish such as the silver hake, spotted hake, white hake and haddock do not act like red hake.  Red hake are the same color as the scallop. Coincidence?  Maybe.

Is the red hake now protecting the scallop as it curls around it?  The scallop protected the young fish for as long as it could, so now is the Red hake returning the favor?  The main predator of the scallop is the starfish.  A starfish would have to climb over the fish to get to the scallop.  The red hake would not allow the starfish to get that far.

Red hake have a swim bladder that erupt when brought to the surface.

Red hake have a swim bladder that erupt when brought to the surface.

Is the red hake still just protecting itself?  When curled around the scallop, the fish blends in with the scallops red color and is in a sense camouflaging itself from its enemies. In this sense, the scallop is still allowing the red hake to hide, but this time in plain sight.

The Atlantic sea scallop is more interesting than expected.  It is curious how the scallop seems to realize how close it is to other scallops.  Without having a fully functioning brain, just groupings of neural ganglia, acting as a control center for a bodily functions or movement, how can the scallop decide the best place to live?  Do they move in search of a better habitat?  How do they know to disperse within their area so they are relatively the same distance apart as seen on the HabCam?  Is it competition for food?

Could it be their photosensitive eyes can’t tell the difference of movement of a predator to that of another scallop?  They seem to be able to tell the difference between a sea fish predator and one that is not.  Why are they so tolerant of the red hake?  More questions than answers.

The HabCam is a wonderful tool for studying these questions and more.  So little is understood about the habitats within the oceans.   It has been easier to study space than to study the depths of our own planet.  This is a very exciting time in oceanic research.  The HabCam will reveal what has been covered with a blanket of water.

Personal Blog:

We spent a little more time at Woods Hole.  Jim, the ship’s captain, hired a crew of scuba divers to scrub off the barnacles growing on the rudder.  I was lucky enough to find a tour of some of the labs at Woods Hole.  Scott called around to his colleagues and discovered there was a tour for teachers occurring at that moment when we arrived.

Alvin the deep sea submersible in dry dock.

Alvin the deep sea submersible in dry dock.

I quickly was sent on a campus bus with Ken, a man working in the communications department, also with a science degree.  I think he said it was in physical geology.  Everyone around here has multiple degrees and they are often opposite what you would imagine.  Such diversity makes some very interesting people to chat with.

In the teacher tour was a former TAS (Teacher at Sea). She was here because she won a touring trip to Woods Hole, so we had some time to chat over lunch about our experiences.  We agreed the TAS is one of the best teacher development opportunities out there for all teachers and I think we convinced a third to apply for next year.

I never got the long walk I had planned on, but a much better one learning more about Woods Hole.  Ken even took me to see Alvin, the deep sea submersible that lives on the Atlantis.  The Atlantis was leaving Alvin behind on its latest mission so Ken showed it to me.  The navy is using it this time.

I’ve been feeling great and even got on the exercise bike.  Today we will be HabCaming the entire day.  It is a nice rest compared to the physical work of dredging from the last two days.  Both HabCam and dredging have their benefits.  Together they create a much better understanding of what’s below us.DSCN7966 (2) lobsters

While I’ve been writing this the wind has picked up 10 knots.  The waves are 4-6 ft high with an occasional 8ft and it doesn’t look like it will let up.  The HabCaming continues but it is harder to keep it level.  They are considering going in early if the weather continues to get worse.  I believe Tasha said we were a bit ahead of schedule so that wouldn’t be so bad for the survey.  Before that happens, there is more dredging to do.

Channa Comer: Crabs and Stars, May 15, 2011

NOAA Teacher at Sea
Channa Comer

On Board Research Vessel Hugh R. Sharp
May 11 — 22, 2011

Mission: Sea Scallop Survey Leg 1
Geographical area of cruise: North Atlantic
Date: Monday, May 15, 2011

Weather Data from the Bridge
Air Temperature: 16.2C, Mostly Cloudy
Wind Speed: 11.6 knots
Water Temperature: 13.4C
Swell Height: 1.0 meters

Science and Technology Log
Question of the Day (See the answer at the end of the post)
How do you count a basket of crabs?

It’s hard to believe that we’re already at the halfway mark of the cruise. Since my last log, we’ve covered a total of 966 nautical miles. Today, we’ve traveled from Hudson Canyon which is 60 nautical miles east of Atlantic City to about 50 nautical miles from the coast of Point Pleasant, NJ.

Bucket of Crabs

Bucket of Crabs

Each day, the boat stops at predetermined points along the route. At each stop, the scallop dredge is lowered to the ocean floor at depths ranging from 15 to 60 fathoms. The dredge is then towed for 15 minutes at a speed of 3.8 knots. When 15 minutes has passed, the dredge is brought up and the catch is dumped onto a platform were we all wait anxiously to see what comes up. Once the empty dredge is secure, we get to work sorting the catch. Scallops and fish get separated, with everything else collected into baskets, cataloged as “trash” and returned to the ocean. The scallops are measured, and the fish are sorted by species, then counted, weighed and in some cases saved for further scientific study back at NOAA labs. Once everything has been counted, weighed and measured, it’s time for my favorite activity – shucking! Scallops are shucked and if there’s time, washed bagged and placed in the deep freezer for Paul to use in the galley for meals. To date, we’ve completed 90 tows and dredged 23,212 scallops.

What comes up at each catch depends on the location of the tow. The southernmost, areas that have been open, or those areas that have recently been closed will usually yield fewer scallops. Scallop yields increase as we head northward and in areas that are closed to fishing. In addition to scallops, our tows have included a variety of deep sea fish, starfish, lots of live sand dollars (with their accompanying green slime), and very often, mud.

At select tows, representative samples of scallops are processed beyond the usual length measurements. The shells are scrubbed clean and weights are recorded for the meat and gonad (reproductive organ). The shells are then labeled and bagged for transport to the lab where they will be aged. The age of scallops are determined by counting the number of growth rings on the shell – similar to counting rings on a tree.

Every three tows is my favorite – Crabs and Stars!! In this tow, in addition to the usual sorting and measuring, all Cancer crabs are collected, counted and weighed and a representative sample of starfish are sorted by species, then counted and weighed. Astropecten, a small starfish is a predator of scallops and the most abundant species of starfish that we’ve counted. Usually, a tow that has large numbers of Astropecten has very few scallops. Being a stickler for detail, having the job of counting starfish has been perfect for me.

Did you know?
Starfish eat a scallop by attaching themselves to the scallop in numbers, forcing the shell open, then extruding their stomachs into the shell and digesting the meat.

Animals Seen
Dolphins
Red Hake
Sea Mouse
Chain Dogfish
Little Skate
Four Spot Flounder
Red Sea Robin
Sea Urchin
Snake Eel
Ocean Pout
Sand Dollar
Sand Lance
Goosefish
Starfish
Gulf Stream Flounder
Black Sea Bass
Hermit Crab
Sea Raven

Personal Log
Day 3 – Thursday, May 12, 2011
With my sea sickness over after the first day and having adjusted to my new sleep schedule — I actually get to sleep a full 8 hours! — the days are starting to take on a nice flow. It’s been great being part of a team. We’re like a well-oiled machine. Everyone in my crew continues to be generous, sharing the best shucking techniques and giving me a little extra time to take photos and collect samples. We’ve jokingly renamed the “crabs and stars” tow to “crabs, stars and mud”. It’s really hard to count starfish when they’re covered in mud. Dinner was especially delicious today with salmon in pesto sauce with potatoes and broccoli.

Day 4 – Friday, May 13, 2011
The day started out cloudy and overcast, but the sun made an appearance late in the afternoon. The first tow of the day was my favorite — Crabs and Stars!! — with accompanying mud. As part of the Teacher at Sea program, in addition to my logs, I am required to write a lesson plan. I’ve started to draft what I think will be a great unit using the sea scallop as a springboard to explore issues in ecology and the nature of ecological science. Highlights will be an Iron Chef style cooking competition using scallops and a design challenge where students will have to build a working model of a scallop dredge. Vic has been great with providing whatever data, materials and background information that I need for my lessons. Lunch today was chicken burritos with fresh, spicy guacamole.

Day 6 – Sunday, May 15, 2011
Since its Sunday, I decided to take it easy and instead of trying to get a lot done before my shift and during the breaks, I took it easy and watched a little TV. With satellite TV and a large selection of DVDs, there are always lots of options. Although the guys tend to prefer sports or reality TV. The first few tows were back to back which meant little time for breaks, or snacks, or naps. Just enough time to clean up, shuck and be ready for the next tow.

Day 7 – Monday, May 16, 2011
The trip is half over. It’s hard to believe. The tows were once again, back to back with a fair amount of scallops, but I think after today, we won’t need to shuck anymore. Yay! Today was the day that the animals fought back. I was chomped by a scallop and a crab! The scallop was more of a surprise than a pain, but the crab clawed right through my glove. After days with no restrictions, we received the warning from the engineers today that we have to be careful with the faucets. Dripping faucets waste water and it takes time for the water to be converted through condensation in the condenser to usable water. If we’re not more careful, we’ll be faced with restrictions on how much water we can use……… I hope that doesn’t happen since I think we all officially smell like fish. Lunch today was cream of asparagus soup, yummy and reminiscent of my recent trip to Peru. The only thing missing was Quiona. And finally, today was the day that I’ve been waiting for. I found my favorite ice cream. I’ve been rationing myself to one per day, but after I found my favorite – butter pecan ice cream sandwiches – I could not resist a second.

Answer to Question of the Day: Very carefully!