Science for Everyone

scallop

Scallops, and Clams, and Mussels, Oh My!

Post by Bailey Moritz, Scallop Research Intern

Mussel jackpot! We’ll put these guys back to grow bigger.

The dock has become my office. Since retrieving the spat bags in late July, I have been whiling away the hours, fog or shine, sorting and measuring the baby scallops in all 35 bags that we collected. Eventually, we will map the data to get a picture of where in Penobscot Bay scallop settlement is higher, which can inform fishery management policy. Even though my scallop count is a whopping 14,000 and counting, I can still say that baby scallops are adorable and surprisingly entertaining. These tiny guys are anywhere from 0.1 to 2 cm in height. By rapidly clapping their shell halves together, they can propel water and thus swim to the surface of the jar I collect them in. Check out Hurricane Islands Instagram for a great video of this phenomenon! My swimming jar of baby scallops has been an excellent show and tell for visitors and students pulling up on the dock. In addition to their cute little performance, juvenile scallop shells have colorful and varied patterns worthy of being called art.

An invasive form of encrusting tunicate forms orange and black mats on the mesh. The little white shapes are clams!

Baby scallops come in a beautiful array of colors and patterns that they’ll eventually lose in adulthood.

Mesh spat bags are not selective. Any larvae floating in the water column can enter the bag and start to grow. While there are upwards of 500 scallops in each bag, there are usually more than 5000 little clams filling the bag as well. Thank goodness I’m not counting clams! The spat bags came from different locations in Penobscot Bay, and you can tell. Each spat bag displays distinct characteristics from the others. One might have lots of healthy juvenile mussels hanging on tight with their byssal threads. Another may have only larger scallops compared to bags with handfuls of practically unseeable small ones. A number of bags contain starfish, thought to be a predator to the scallop, which might be the cause behind a number of empty, crushed shells. I have seen 7 species of beautiful sea slugs, called nudibranchs, and am now well acquainted with tunicates and sea squirts that find the thick blue mesh a perfect point of attachment. I won’t say the number of times I’ve accidentally squirted myself (or others) in the eye trying to peel them off the bags.

Over the course of the past month witnessing the ebb and flow of the tides from my workspace, I have come to appreciate the diverse and unique ecosystem that is a spat bag. What may at first appear to be a mess of muddy shells, shrimp, and slime, actually holds a snapshot of a coastal marine world in an early stage of growth. I still have a few more spat bags to pick through. But with the dock as my office and swimming baby scallops to keep me company, I really can’t complain.

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Learning from Shells

Post by Scallop Research Intern, Bailey Moritz

Toni Chute and I start the task of aging the first scallop of several boxes of scallop shells

Bustling with research vessels and ocean scientists, Woods Hole, MA is a fitting location for the Northeast Fisheries Science Center, located right on the water. Toni Chute, one of their scientists specializing in all things scallops, was generous enough to give Cait and I a run-down on how to determine the growth of individual scallops based on their shells. Cait will be using these data as part of the collaborative scallop research project she is coordinating. Scallop shells are formed from calcium carbonate that the shellfish precipitates over the course of its lifetime. Depending on what region of the ocean it grew in, pigments vary, from a rich pink to deeper purple to the rusty red color seen on most scallops here in Maine. The shell-building material is laid down during a period of the year when conditions, such as temperature and food availability, are favorable. Then growth stops for awhile. This pattern creates rings, or visible line markings on the shells surface, that indicate each year of growth the scallop has undergone. By measuring the change in height between rings, you can elucidate how much the scallop grew from year to year. But be careful! As we learned, false “rings” can form if the shell cracked, or was damaged slipping through the large rings of scallop dragging nets when they were still below legal harvest size.

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       Measuring a shell with each of the         growth rings marked off in pencil.

     Measuring a shell with each of the  
      growth rings marked off in pencil.

Determining growth rings can be a tricky task. The surface of some shells have a heavy cover of barnacles and limpets that make it difficult to see the patterns. Often times you can turn to slight changes in color to pin-point the rings, and getting the shell wet and holding it up to the light helps to bring that trait out. We practiced on a number of our shells collected from Muscle Ridge and were still somewhat hesitant in distinguishing between growth rings and cracks. But Toni reassured us that familiarizing ourselves with the shells patterns makes finding rings easier. It’s also perfectly alright to eliminate a shell from your sample if you’re finding it’s just too difficult to tell where the annual growth rings are. So, next time you come across a scallop shell on the beach or at the market, try your hand at finding the growth rings and you’ll be told a story about the creatures path from small spat to adulthood. 

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20th International Pectinid Workshop in Galway, Ireland

Conducting drop camera surveys on Muscle Ridge in 2013.

Conducting drop camera surveys on Muscle Ridge in 2013.

I booked my flight to Shannon, Ireland on St. Patrick's Day! In early March 2015, I found out that two abstracts I submitted on behalf of the scallop project team were accepted to be presented at the 20th International Pectinid Workshop in Galway, Ireland. The workshop has been organized around several themes including general scallop ecology and biology, aquaculture, fisheries management, and marine protected areas. The event will bring together scientists, managers, and others who work on scallop fisheries research. It provides an amazing opportunity to build my foundational knowledge on scallop biology, plus get some helpful hints on how to improve our project or other potential analyses to do to understand the effectiveness of small-scale closures in rebuilding the resident scallop population. I also have the opportunity to co-chair the plenary session - Marine Protected Areas with marine ecologist and fisheries biologist, Bryce Beukers-Stewart.

My oral presentation will be entitled, "The effect of small-scale closed areas on giant sea scallop populations in Maine" and the poster will focus on the collaborative project approach including lessons learned through working with a diverse group of fishermen, managers, and scientists. I am looking forward to writing additional blog posts to share what I learn while at the workshop. 

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The Height of Our Scallop Research Season

This summer has been not only busy on-island with student programs, but also a busy field season collecting data for our collaborative scallop research project. In July 2014, we were awarded a grant administered by Maine Sea Grant with funding from the Maine Community Foundation and the Broad Reach Fund. In early August, we started conducting our second year of dive surveys on Muscle Ridge and Ocean Point.  So far we have completed a total of 16 dive surveys on the Ocean Point scallop closure (you can read more about how this project has been set up here), and surrounding area to assess scallop abundance and to collect samples. These surveys have been conducted with the help of scientists from the Maine Department of Marine Resources and from our HIF science advisor, Dr. Rick Wahle's Lab based at the University of Maine's School of Marine Sciences. I've also been able to work alongside Susie Arnold, the Island Institute's marine scientist, to dive on Muscle Ridge. We've completed 8 sites so far and are hoping to get a few more days of diving in before fall officially arrives!

On September 11, 2014, a crew from Dr. Kevin Stokesbury's lab based at the University of Massachusetts at Dartmouth arrived in Maine and set up their drop camera rig on Tad Miller's dragger, F/V Julie Ann in Tenants Harbor. We then did three days of drop camera surveys on Muscle Ridge. To identify the sampling stations, we laid a 200 m x 200 m grid over the survey area and marked the center of each cell. We would then steam to the latitudinal and longitudinal coordinates of that center point and drop the camera to the bottom to take footage of the life below.  Fortunately, we did not have any major technical difficulties and were able to increase the number of sites we sampled this year as compared to October 2013 where we lost a cable which limited our ability to sample deeper sites. 

This weekend (September 19 - 21, 2014), I will work with one of our industry partners to set the spat bags out which will then be collected and processed next June. I hope we are able to wrap up the field work by the end of October then on to analysis and preparing for the 2015 field season!

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License to Kill... in the Name of Scallop Research!

Atlantic Sea Scallop (  Placopecten magellanicus)

Atlantic Sea Scallop (Placopecten magellanicus)

We were recently approved for our 2014 special license through the Maine Department of Marine Resources (DMR). We are required to file a special license application for our research because we are asking for an exception from existing legislation that prohibits collecting undersized scallops, tissue and shell samples. The tissue samples are being saved for genetic analysis which will help us understand the connectivity between different scallop population locations, and we will also keep the shells from each individual collected for aging and growth rate analysis. 

The DMR Application describes the purpose of our project, how project findings might be useful in future management decisions, the specific activities we will be carrying out as part of the project, and gear types used to collect samples. For this application, we worked with Kevin Rousseau, who is part of the regulations, hearings, and special licenses division of the DMR.

Special license applications are reviewed and voted for approval by the Department's Advisory Council, which is made up of 16 members: five commercial harvesters who each represent a different fishery, four people who hold a non-harvesting-related license, a recreational fishing representative, a member of the public, and an aquaculture industry representative. The chair of the Lobster Advisory Council, the chair of the Sea Run Fisheries and Habitat Advisory, the chair of the Sea Urchin Zone Council, and the chair of the Shellfish Advisory Council are ex officio members of the council. 

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