Tag: ocean quahog

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Anne Artz: July 27, 2011

NOAA Teacher at Sea
Anne Artz
Aboard NOAA Ship Delaware II
July 25 — August 5, 2011

Mission: Clam and Quahog Survey
Geographical Area: North Atlantic
Date: July 27, 2011

Weather Data from the Bridge
Location:  40 08.301N; 72 07.278 W
Direction:  1140
Wind:  NW @ 10
Conditions:  Breezy, choppy water but warm and sunny, very few clouds

Science and Technology Log

We had an interesting night last night – quite a show from the lightning all around us.  We had to stop working on deck due to lightning concerns and the water was definitely choppy.  Shortly after midnight we resumed our survey dredging

A little history and information about the ocean quahog is in order, since we’ve been spending most of our time the last few days collecting, counting, weighing, and measuring them (along with a few other things we dredge up – more about those later).

The ocean quahog, or Artica islandica, is a marine bivalve member of the phylum Mollusca.  It is native to the North Atlantic (where we are right now) and is commercially harvested as a food source.  The ocean quahog lives in deeper water than the more common clam (the ones you can dig up along the beach) and are collected in much the same way as we are doing on the Delaware II, by dredging the bottom, rinsing off the mud, and throwing away all the other things brought up.

We bring up any where from one to three baskets of ocean quahogs with each dredge.

One of the unique characteristics of the ocean quahog is its longevity.  They are known to live over 100 years.  They are extremely slow-growing and as adults, may take years to add any measurable length to their shells.  Both water temperature and population density appear to play a role in their growth.  From previous NOAA studies, some of the fastest growing populations occur at the Georges Bank region off the coast of Massachusetts.  The National Marine Fisheries Service (NMFS) uses the data collected from this survey to advise policy makers on the best way to protect and ensure the survival of the ocean quahog populations.

So what do we know so far about the ocean quahog’s populations?  Besides the fact that they grow slowly, we know they are suspension feeders of phytoplankton and they themselves are food for a variety of other invertebrates including crab, sea stars, urchins, and some fish such as cod.  The dredging process damages some ocean quahogs making them susceptible to other predators such as sculpin, skates, and flounder.  Every three years the populations in the Northern Atlantic are surveyed and past results indicate the populations are stable despite the dredging methods of collection.  The ocean quahog is not considered endangered at this time and is not considered overfished.

Personal Log

The lightning storm was beautiful to watch – the only  thing missing was the thunder!  Our ship never stops so the engines run continuously, making hearing anything on deck almost impossible.  We’ve brought up some incredibly interesting animals – some I’ve never seen or heard of.  For example, we’ve brought up numerous “sea mouse” samples.

Sea Mouse
A sea mouse, or Aprodita aculeata (member of phylum Annelida)

They are actually carnivorous worms who live on the ocean floor and are covered with long hair-like threads, or setae.  The ones we’ve brought up are 4-6 inches long. Creepy!

We are currently at survey site 229 which for you students translates to trial number 229.  No more complaining to me about having to repeat your experiment 25 times!

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Anne Artz: July 26, 2011

NOAA Teacher at Sea
Anne Artz
Aboard NOAA Ship Delaware II
July 25 — August 5, 2011

Mission: Clam and Quahog Survey
Geographical Area: North Atlantic
Date: July 26, 2011

Weather Data from the Bridge
Location: 40 32.672 N070 43.585 W
Temperature: 18.5 C
Winds:  Easterly at 3-4 knt
Conditions:  Sunny today, some clouds, ocean calm

Science and Technology Log

Our first full day at sea (and at work)!  We left the dock at Woods Hole, MA yesterday at 2 pm and headed out past Martha’s Vineyard and Nantucket.  While steaming towards our sampling site, we practiced two very important safety drills — a fire drill and the abandon ship drill.  The abandon ship drill was unique in that we had to don our survival suits (supposedly in a minute but I think I took longer than that) that protect us in the water from hypothermia and also help keep us afloat.

Survival Suit
Anne Artz in her survival suit

Around 6 pm we reached our first sample location and the “day team” (that’s me and some fellow volunteers) started our work.  The testing protocol is fairly simple: sample sites have been predetermined by computer.  Survey sites are selected based on depth and location (latitude and longitude).  When we reach those locations, a large sled-like cage called a dredge is lowered into the water and dragged along the ocean floor for a prescribed amount of time (generally 5 minutes).

Sampling dredge on the Delaware II
This cage goes on the ocean floor scooping up samples for our analysis.

The dredge is then brought up and the contents emptied onto the deck.  Our work then takes 10-15 minutes to sort through what is brought up, keeping those items we are surveying or counting, and throwing the rest back into the water.  We attempt to identify organisms we bring up and we count all live bivalves, any gastropods, hermit crabs, starfish and all fish.  Species we identify and measure are the surfclam, the ocean quahog, the southern quahog, and sea scallops.  Once we’ve separated out what we need, we weigh the catch then measure the size of each item collected.  We throw everything back into the water and clean up the deck while heading to our next location.  The procedure is repeated about twice each hour.  For our work on the deck we wear protective clothing, hard hats, and of course, a life vest.

Personal Log

There are seven volunteers aboard this trip, including myself.  They are a varied group from all over but are all very interested in ocean science.  Some of them are college graduates, some are still in college and we are all first-timers on this type of research vessel.  We were assigned a 12-hour shift, either noon to midnight or midnight to noon.  I feel fortunate to be on the noon-midnight shift as that means I don’t have to alter my sleeping pattern much.  It’s tiring work but the good part is there are breaks between each haul so most of us have our books with us on the deck (so handy to have a Kindle!).  The crew here is as varied as the volunteers, from all over the country and they are all very good at what they do.  I initially thought having 4 girls sleeping in a room the size of a walk-in closet would be difficult but it’s not.  At any given time two of us are on deck, on duty, so the room is available for sleeping, changing, showering, etc.  We all respect quiet below deck because at any given time, someone is always trying to sleep!

Interesting Things Seen Yesterday

A shark with a rather large fin above the water was following us from a distance for a while — maybe curiosity?  We brought up several skates (they look like rays) the largest being about 12 inches long.  They are incredibly beautiful up close, looking almost angelic.  It seems a shame they have such a bad reputation!

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Anne Artz: Introduction, July 14, 2011

NOAA Teacher at Sea
Anne Artz
Aboard NOAA Ship Delaware II
July 25 — August 5, 2011

Mission: Clam and Quahog Survey
Geographical Area: North Atlantic
Date: July 14, 2011

Personal Log

I’ve spent most of my life on the west coast, about a mile from the beach.   I teach Environmental Science and Biology to high school students and we frequently visit the Pacific Ocean to collect data.  This summer, I am doing research on the east coast leaving from Woods Hole, MA aboard the NOAA Ship Delaware II as part of NOAA‘s Teacher at Sea Program.

NOAA Delaware II
NOAA Ship Delaware II

I’m excited about our experiment – collecting data about the Sea Clam and Ocean Quahog.  My students already have a summer reading project about the particular species we are looking for and I hope to be able to share some new information with them when school begins in August.

I love the outdoors and am looking forward to a new adventure at sea in the Atlantic Ocean. I’m guessing it’s going to be different seeing the sun rise over the ocean instead of setting.