Nature Blog Network

Thursday, October 15, 2009

Iceland Scallop

Time to celebrate the funding of Mrs. M.'s project, Coral Reef Flip Books, part of the Ocean Bloggers Oceans in the Classroom Initiative. Yesterday I asked for input on which card to feature, and the results are in: with 33.33% of the "vote" the Scallop of Hearts gets the next preview here. I should note that the picture on this card is likely to change before the final version, when we hopefully will get an image of a live animal without too many epibionts (organisms that live on the surface of another living organism, generally a commensal relationship) on the valves.

Classification for the Icelandic Scallop







C. islandica


It is thought that the Chlamys genus originated in the Pacific and expanded into the Atlantic. Fossil Chlamys shells have been found dating to the Miocene in California. In the Atlantic ocean fossilized shells of the Icelandic scallop (Chlamys islandica) have been found from the late Pliestocene, when it ranged as far south as Long Island in the west Atlantic and to the Mediterranean in the east. Today it is found from Hudson Bay to Cape Cod in the western Atlantic and along the coast of Norway in the eastern Atlantic. It is also found in the fjords and waters of western Greenland and Iceland.

The Iceland Scallop (C. islandica) is the northernmost occurring of the major commercial species in the Pectinidae family, occurring in sub-arctic waters of the Atlantic. Several similar species, once thought to be subspecies of C. islandica, are found in similar areas of the sub-polar Pacific. In many areas of C. islandica's range, it is, or has been, a major fishery species. In recent years however in much of its range the fisheries have collapsed.


In most of Norway the fishery for the Icelandic scallop suffered complete collapse in just three seasons and has only recovered in one location. In Iceland the stock is (as of 2008) only at 13% or less of its size just one decade earlier. The causes of the rapid decline in Iceland have been investigated by several researchers. They have determined that overfishing has had a strong impact on the stocks, but the effect has been magnified because of two environmental factors. A protozoan parasite is affecting large numbers of adults, causing increased adult mortality. Sea bottom water temperatures have increased more than 2°C, possibly contributing to both adult mortality and very poor juvenile recruiting years for the past four years, take a moment to think of the implications of climate change for this species. Because of all this, the fishery was recommended for closure in the 2009 and 2010 seasons.

North American stocks have not fared much better in recent years, with strong declines in stocks. The sharp stock declines worldwide coupled with the fact that they are only wild-fished using dredges, which extensively alter the hard bottom habitats where they live, have caused organizations, such as the Blue Ocean Institute, to recommend avoiding this particular species when possible.


Icelandic scallops have separate sexes (gonochoristic) from birth, whereas most scallop species are hermaphrodites. Reproduction is by broadcast spawning, which is cued by rising ocean temperatures in June and July. After 6-10 weeks of floating as planktonic life, the larvae settle to hard sand and gravel surfaces. When settling they preferentially attach to dead hydroids, live hydroids, and algae using byssus threads.

Growth rate varies seasonally, by age, and across the species range, but the scallops generally reach maturity at 5 or 6 years old and can live in excess of 23 years.
Icelandic scallops are largely sedentary, often with large and dense coatings of epibionts, such as sponges and tube worms.

One thing that interests me right now about the Icelandic scallop, mainly because I'm spending my days doing a lot of GIS work now, is that the species is extremely temperature sensitive, with both high and low temperature limits. As the sea surface and bottom temperatures change, the stock densities and distribution of the scallop change as well. Similarly, it has known constraints in salinity, current flow velocities, depth and sediment types. This makes the Iceland scallop a good choice for a GIS-based habitat suitability modeling, using the range of potential climate change parameters to predict future range contractions or expansions and areas where stock recovery efforts or aquaculture are most likely to succeed over the long term.

Of course I also love scallops for their beautiful eyes, and yes... their taste!
I think this is one of my favorite recipes. I don't recall where it comes from originally or I'd credit it. Just make sure to use farmed or wild caught Bay scallops (Argopecten irradians) or Giant scallops (Placopecten magellanicus), not Icelandic scallops.

12 scallops
Sea Salt
2-3 tbsp olive oil (virgin)
4 tbsp chopped onion
1-2 tbsp chopped garlic (we go 3, we love garlic!)
1 dry bird pepper (or use dried thai pepper)
3 tbsp parsley
3 tbsp diced prosciutto
Fish Broth (splash)
12 clams

Sprinkle pinch of sea salt over scallops and let sit 5 minutes. In preheated pan on medium heat, add oil, onions, garlic and thai pepper. Cook until onions are wilted. Add scallops and pinch of saffron. Continue to cook on medium 3 more minutes. Add splash of fish broth, splash of sherry, clams and prosciutto. Cook additional 30 seconds to 1 minute. Serve with rustic bread.


Arsenault, D., Giasson, M., & Himmelman, J. (2000). Field examination of dispersion patterns of juvenile Iceland scallops (Chlamys islandica) in the northern Gulf of St Lawrence Journal of the Marine Biological Association of the UK, 80 (3), 501-508 DOI: 10.1017/S0025315400002198

GARCIA, E. (2006). The Fishery for Iceland Scallop (Chlamys islandica) in the Northeast Atlantic Advances in Marine Biology, 51, 1-55 DOI: 10.1016/S0065-2881(06)51001-6

Jonasson, J., Thorarinsdottir, G., Eiriksson, H., Solmundsson, J., & Marteinsdottir, G. (2006). Collapse of the fishery for Iceland scallop (Chlamys islandica) in Breidafjordur, West Iceland ICES Journal of Marine Science, 64 (2), 298-308 DOI: 10.1093/icesjms/fsl028

WROBLEWSKI, J., BELL, T., COPELAND, A., EDINGER, E., FENG, C., SAXBY, J., SCHNEIDER, D., & SIMMS, J. (2009). Toward a sustainable Iceland scallop fishery in Gilbert Bay, a marine protected area in the eastern Canada coastal zone Journal of Cleaner Production, 17 (3), 424-430 DOI: 10.1016/j.jclepro.2008.08.004

1 comment:

  1. After a bit of feedback from my folks I should note, unless you like your food fiery, leave the pepper whole! Sorry Mom!


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