Search Results for: bivalve

Getting to know three … Bivalve edition

Ever know instinctively that some animals are ‘related’ and just can’t pinpoint their similarities? On the third day of every month I explain three features that are common among three animals of a certain group. Of course, generally each group has more than three representatives and even  many more similarities and then even more differences, but I am going to choose three similarities that link threes to keep it simplified. This month is focused the mussel, scallop, and clam. These three animals are all part of the bivalve group which is the second largest group of mollusks. The largest group of mollusks are the gastropods. Mollusks are well-known for their soft, unsegmented bodies and shell covering (although cephalopods do not have this feature). Check out the image below to learn what the featured animals all have in common.




20 reasons oysters are awesome

O-Y-S-T-E-R! Happy National Oyster Day! There needs to be much love for the oyster. These creatures are delicious, sustainable, and help the environment. Maybe we need more than just one day to celebrate this bivalve? If you don’t believe me, here are over 20 reasons oysters are awesome:

  1. Oysters spawn during the summer months and therefore tend not to be as tasty. This is the epitome of the old wives’ tale on why “you shouldn’t eat oysters in months that don’t end in ‘R’.”
  2. Another reason this adage has prevailed is that oysters are much better when cold and do not taste that good when in the heat.
  3. Oysters can change their sex. They can produce both semen and eggs.
  4. Oysters have been known to live up to twenty years in captivity.
  5. When oyster larvae attach to a hard material, a vital part of their life cycle, they’re called “spat.” Two to three years later they are considered adults.
  6. The habitat of the Eastern American oyster (Crassostrea virginica) extend from Canada to Argentina.
  7. Even though there are countless (and delicious) varieties of oysters there are only five species. These species are the Pacific oyster (Crassostrea gigas), Kumamoto oyster, European flat oyster, American (i.e., Eastern) oyster, and the Olympia oyster. The shells of the five species are truly what sets these species apart (other than the geographic region they are most often found). The American is pretty familiar with its large size and comma shaped shell. The Olympians have a small, round, pale shell with lustrous coloring. The Kumamotos have a round, pale shell as well but not as much of a smooth shell. The European flat has fine ridges around its large, straight shell, and the Pacific are small with wavy shells. In fact, the same type of oyster can taste different contingent on where it was raised.IMG_7313
  8. Sometimes a bacteria that commonly grows along coastal environments where oysters are found known as Vibrio vulnificus can infect the oysters. This would leave to that “bad oyster” that might make you sick.
  9. One very common misunderstanding of the oyster is that they are an aphrodisiac. However, it’s really just their significant amount of zinc. Zinc is a mineral that will boost your energy and therefore can boost your sex drive. Other benefits of zinc are that skin will improve and make your bones stronger.
  10. Oysters also have immense amounts of omega-3-fatty acids which can sharpen your memory, lower levels of depression and heart disease, as well as a host of other benefits.
  11. Oysters also have lots of vitamin A, C, D and B-12.
  12. Even though Boticelli’s “The Birth of Venus” has Aphrodite rising from the sea on a scallop shell legend has it that the Goddess of Love, Aphrodite, emerged from the sea in an oyster shell.
  13. In the 17th century, New York City was covered in oyster beds and were very much enjoyed by the native Lenape Indians. Eventually, by the 19th century, the oysters were so plentiful that raw oysters could be purchased from the street vendors. There was even oyster saloons with all sorts of methods for consuming oysters.
  14. Most pearls found in jewelry are from clams and mussels – not oysters. Although, there are also actual pearl oysters which are from a different family of bivalves.
  15. Oyster mushrooms and black salsify, also called “vegetable oyster”, actually taste like oysters.
  16. Oysters are a crucial member to the aquatic communities. Not only do they gobble up lots of algae (think of your back bay becoming a dirty fish tank without them), but they are crucial as natural filter feeders. Oysters filter approximately 30 to 50 gallons of water a day removing excess nutrients and allowing shrimp, clams, crabs, and snails to flourish. The cleaner water also enables more seagrass to grow creating more habitat for fish.
  17. Oysters grow on top of one another as an oyster reef. These huge substrates are imperative for soil erosion and shoreline stabilization.Oyster_human_impact_diagram_SM_noaa
  18. If you bring home oysters for your next bake be sure to recycle the shells close to home. The shells of the oysters are extremely rich in calcium and can help balance the pH of the soil as well as add nutrients to your garden. Fertilizer fresh from the sea!
  19. Oyster farms, unlike other types of fish farming, can greatly enhance the health of nearby waterways. Not only do they tend to munch on pollution (yes, they’ve been known to help out Big Oil), but if the oyster were to escape it isn’t in danger of becoming an exotic species.
  20. While it’s all well and good that farmed oysters can do a lot to help water quality … natural oysters reefs are just as vital. Unfortunately, 85% of the global oyster reef population has been lost.
  21. In the Chesapeake Bay an estimated 2,600 acres of oyster beds are lost each year because of runoff and silt. On the Pacific coast invasive crabs and snails are destroying natural oyster beds.
  22. Not only are oyster reefs vanishing, but the ones that remain are just not as strong due to ocean acidification (i.e., climate change for the sea).
  23. There are many organizations along the Atlantic coast that are looking for volunteers to help adopt and raise oysters. If you don’t live on the water volunteers are still urged to build oyster reef substrates or oysters mats.

Resources: Food Republic, NOAA – Cheasapeake Bay Office, Organic Life, Oyster Recovery Partnership.

Nudibranchs: The elusive butterflies of the sea

The 3,000 species of nudibranchs (noo-duh-brangk) boast more colors than a box of Crayola crayons and most nudibranchs “live no more than a year and then disappear without a trace, their boneless, shell-less bodies leaving no record of their brief, brilliant lives”.

These sea slugs are found all over the world and range in size from a quarter of an inch to just about a foot. The word “nudibranch” means “naked gills”. A name appropriate since their gills are exposed prominently outside of their bodies (not covered like other sea slugs).

These gastropods are remarkable for their defense mechanisms. A listing and description of some are listed below along with some select images of these brilliantly colored sea slugs.

Warning coloration: Bright, contrasting pigments warn prospective predators they’re are inedible.
Skin: They can be can be tough-skinned, bumpy, and abrasive.
Toxic secretions: Some feast on poisonous sponges and then absorb the toxins into their body which are secreted later when disturbed.
Stinging cells: Some accumulate the stinging cells (nemocysts) from their prey (e.g., fire corals, anemones, and hydroids) and then the stinging cells are emanated from their own body when distributed.





I must admit that the title and inspiration of this post came from the book “The Highest Tide” (2005) by Jim Lynch. If you have time this summer it’s a must read if you think you might enjoy an homage to Rachel Carson secretly embedded in a coming of age story set along the coast of Puget Sound.

Image (c) top to bottom:

Molly Malone’s cockles and mussels

On the way home from work yesterday I had a driveway moment and could not stop listening to a story on All Things Considered on the benefits of forgoing the pub this Sunday and instead preparing some heartwarming Irish food at home to celebrate Erin go bragh. The story featured a recipe – Molly Malone’s Cockle and Mussel Chowder – from Rachel Allen, a popular Irish TV Chef, and I got to thinking on how I think it’s time to briefly feature those bivalves on Beach Chair Scientist! Here are 5 facts about cockles and mussels so you can have some fodder if you like to pretend to be the host of a show while cooking for your family.


Cockle shells

Cockle shells

  1. There are more than 200 species of cockles.
  2. Cockles have a distinct rounded, heart-shaped shell with ribs that fan out through the length of the shell (they’re actually evenly spaced on the exterior of the shell).
  3. Cockles prefer intertidal areas with sand and mud beaches and depths up to 60 feet. Cockles are distributed world-wide, but the common cockle (Cerastoderma edule) is found widely distributed around the coastlines of Northern Europe (extending west to Ireland, the Barents Sea in the north, Norway in the east, and as far south as Senegal).
  4. Cockles move with a powerful muscular foot. They’ve even been witnessed springing with this strong foot on the bottom of the ocean floor.
  5. Cockles are not important commercially.



Mussel shells

  1. Mussels have wedged-shaped, asymmetrical shell that is longer than wide. They’re typically dark blue, blackish, or brown, while the interior is silvery and somewhat nacreous.
  2. Mussels are filter feeders and feed on plankton and other microscopic, free-floating sea creatures in seawater.
  3. Mussels provide shelter and protection from heat, desiccation, and predators for many smaller marine organisms.
  4. According to Wired, “Chemists recently made prototype bandages with an inkjet printer filled with adhesive proteins taken from mussels, whose remarkable “feet” — a tangle of fibers that anchor them to rocks — have made them the most widely studied specialist in marine clinging”.
  5. 90% of the world’s mussels are cultured, with the major producers being China, Spain, Italy, Thailand, France, and New Zealand. Don’t fret, the U.S. has tough regulations on its imports of mussels.

Click here for the lyrics to the Irish song Cockles and Mussels, or Molly Malone. Erin go bragh!

17 facts about the wee sea potatoes

In honor of St. Patrick’s Day, and my Irish heritage, here’s a post on the humble and charming sea potato.

  1. The dried shell (also known as the test) of this urchin resembles a potato, hence the common name – sea potato.
  2. The sea potato, Echinocardium cordatum, is a common echinoderm found along beaches on all coasts of Britain and Ireland.
  3. The sea potato is related to sea urchins, heart urchins, and sand dollars.
  4. Most sea urchins live in rocky areas, but the sea potato prefers sand, particularly muddy sand.
  5. The spines of this echinoderm are thin and flattened.
  6. On the underside of the urchin are special spoon-shaped spines that help it to dig.
  7. There are longer spines of the back of the sea potato which aid in helping to breathe while it is burrowing.
  8. The sea potato can survive to depths of 650 feet.
  9. Unlike regular urchins, the sea potato has a distinct front end (i.e., not circular).
  10. The sea potato can grow up to 3 inches.
  11. The sea potato is very fragile and rarely survives collection.
  12. While alive the sea potato is deep yellow in color and covered in fine spines.
  13. The sea potato prefers sub-tidal regions in temperate seas.
  14. The sea potato are a type of heart-shaped urchin.
  15. Sea potato are deposit feeders and tube feet on its underside the sea urchin pick up sediment from the front of its mouth.
  16. The sea potato has no conservation concerns.
  17. The sea potato often has a commensal symbiotic relationship with the bivalve Tellimya feringuosa attached to its anal spines.

A sea potato, commonly found along the shore of Ireland


The test of the sea potato


The underside of the sea potato

Jingle shells, jingle shells, jingle all the way

Oh, you know it’s stuck in your head. If not the Christmas carol, than the image of the beautiful shell that leaves a twinkle in the sand as you walk along the shoreline. Many people assume jingle shells are juvenile oysters because they’re often attached to them. But, jingle shells are their very own species known as Anomia simplex. Here are 10 facts for you to better get to know this treasured beachcomber’s find.

1. Jingle shells have thin, translucent shell halves that look like frosted nail polish.
2. Jingle shells have also been nicknamed “Mermaid’s Toenails”, “Saddle Oyster”, or  “gold shell”.
3. Jingle shells appear all year and are found in shallow waters, beaches, oyster beds, and mollusk shells as far north as the coast of Nova Scotia, and all the way down south to Brazil.
4. The jingle shell is a bivalve mollusk, similar to mussels, oysters, and scallops, which all have two separate shells or “valves”. The upper valve is rounded and movable. The lower valve is typically flat and forms to the object which it is attached. It has a hole in the top where tufts of filament, the animal’s byssal threads, grow out to attach it to another surface (i.e., Jingle shells are epifaunal just like bromeliads).
5. The raw meat of the jingle shell is sharply bitter to the taste.
6. The jingle shell can reach up to 1-3 inches.
7. The lower valve of the jingle shell remains white, while the upper valve ranges from shiny lemon yellow, golden, brownish, silvery black, or pale buff. The shiny iridescence of the jingle shell is retained even after death.
8. Jingle shells take in water and filter nutritious plankton and other food through ciliated gills.
9. Jingle shells were given their common name because of the sound they make when strung together. Beachcombers often use jingle shells to make jewelry or wind chimes. Julia Ellen Rogers noted in her 1931 The Shell Book that “Pretty lampshades are made by piercing the valves of jingle shells near the hinge and stringing them, then attaching the strands so as to fit over the outside of a plain glass or porcelain shade, whose brightness is pleasantly mellowed by the network of shells”.
10. Fishermen have been known to disperse jingle shells over oyster beds in a process known as “shelling” to create a habitat for oysters can settle.




Colorful coquina clams sign of healthy beach

Those tiny, colorful clams with two siphons poking our of their shells that emerge quickly once the waves wash gently ashore are known as coquina (ko-KEE-nah) clams. These bivalves rarely exceed an inch long and are indicators of a healthy beach. If eroding beaches are constantly being renourished, coquina clams, as well as other sand dwelling invertebrates (i.e., mole crabs), could become buried under the extra sediment. Many beaches have to be renourished because the natural supply of sand from rivers and other sources from the mountains have been impeded by dams and reservoirs. Coquina clams can usually recover their populations if a beach has not been renourished in a year or two.

They tend to feast upon single-celled detritus or algae. Fish, shorebirds, and humans tend to feast upon them. That’s right, coquina clams are found around the world and are enjoyed steamed with butter or even as ‘the basis for a great potato puree‘. In Australia there is a commercial fishery for the meat (God help those processors).

In Florida, you can visit one of my favorite places, Blowing Rocks Preserve, and see the coquina rock outcrop. The coquina rock is a soft rock that is made up of the coquina clam shells (as well as other materials). But, what makes this rock outcrop so unique is that it is part of the largest section rock, known as the Anastasia Formation, from the Pleistocene epoch (2.576 million years ago).

30 reasons to be grateful for the ocean

It’s the end of another National Oceans Month. And, on this most lovely of lovely days I’d like to Speak Up For Blue and name 30 reasons to be grateful for the ocean! (OK, and it just so happens to be this Beach Chair Scientist’s birthday)

In no particular order, here are some reasons to appreciate the ocean (and all its glorious ecosystems):

Estuaries (Although the course may change sometimes, rivers always reach the sea. – Led Zeppelin)

  • Nursery grounds for many of the commercially important fish that live in the sea.
  • Make up the public infrastructure that are the harbors and ports used for shipping, transportation, and industry.
  • Serve as a filter for sediments, nutrients, and other pollutants that come from upstream.
  • Coastal areas are home to over half the U.S. population.
  • Mangroves and other estuarine ecosystems are amazing playgrounds and feeding grounds for many wading birds.
  • The smell of low tide!

Intertidal Zone (including littoral zone)

  • Home to the tides going in and out. Where else can we appreciate the ebb and flow of life?
  • This is home to many bivalve species that love to burrow under the muck.
  • We can investigate the wrack line and find many treasures that have washed ashore.
  • Place where my favorite animal, the Atlantic horseshoe crab, likes to come to mate during the full and new moons in May and June.
  • A perfect spot to jump waves with little ones!
  • Home to the lovely and rhythmic sound of waves lapping.

Coral Reefs (Pollution, overfishing, and overuse have put many of our unique reefs at risk. Their disappearance would destroy the habitat of countless species. It would unravel the web of marine life that holds the potential for new chemicals, new medicines, unlocking new mysteries. It would have a devastating effect on the coastal communities from Cairns to Key West, Florida — communities whose livelihood depends upon the reefs. – Former President Bill Clinton.)

  • Support a great diversity of species.
  • Yield compounds that are very important in the medical field (have been used in the treatment of cancer, HIV, cardiovascular diseases, ulcers, and other ailments).
  • Protect shorelines erosion.
  • Center of many country’s tourism income.
  • Home to a myriad of colors and patterns!

Pelagic Zone, Euphotic Zone (Open ocean)

  • The only place large enough for the big blue whale to swim and play.
  • The only place large enough for a blue fin tuna to pick up enough speed.
  • Home to a lot of phytoplankton that helps support oxygen production.
  • Home to the Sargasso Sea the only place special enough for the American eel to breed.
  • Home to peace and solitude.
  • A perfect spot to become humble.

Mesopelagic Zone, Twilight Zone (Open ocean bathyal zone)

  • Home to the many creature with the beautiful twinklings of bioluminescence.
  • Only place deep enough for sperm whales to dive down and grab some food.
  • Home to many elusive squid species.

Deep Sea (Abyssal)

Polar Regions

  • Home to the polar bear (did you know their fur isn’t white? It is actually clear but appears white since it is reflected in the sunlight).
  • Important breeding and mating areas for many migratory species (including the red knot).

And, without it we’d be nothing. Oceans cover about 70% of the earth’s surface, and we rely on it economically, environmentally, and scientifically.

Obviously this is a very personal list and it could go on and on forever. I am looking forward to hearing your reasons to be grateful to the ocean and hope we can get to 100 by the end of the year!

5 facts about fish farming

Fish farming on Lake Titicaca.

Image via Wikipedia

Here are five facts about the glory and challenges of fish farming. Fish farming and aquaculture has really stepped up due to the demand for the world’s fish consumption, but maybe not in the most sustainable manner like Linda Thornton.

1.) It’s polluting our water

It seems as though large fish farm like to cram fish to live in very tight spaces. A large amount of fish would lead to a large amount of waste produced by the fish. Also, the unfavorable conditions often lead to disease. Fish farmers tend to treat the disease and infection with harmful antibiotics which further harm the surrounding waterways.

2.) It brings untested chemicals to your dinner plate

It seems as though many of the antibiotics used to treat diseases on foreign fish farms are commonly made of chemical banned in the US. Since there is no regulation often these harmful chemicals make their way to your dinner table.

3.) It’s tearing apart mangroves

Shrimp farmers are tearing apart the mangroves to make way for their new crop of this popular crustacean. However, this destroys a delicate nursery ground for many local fish species. In turn this depletion in resources severely affects local economies. What makes matters worse is that often these shrimp farms are abandoned in order to find better producing areas.

4.) It’s often counter-productive

Fish farms can be tough to maintain, especially for salmon and other carnivorous species. They tend to eat more food than they actually produce! This is turn leads to a lot of waste that can disturb the balance of the surrounding waterways.

5.) It does good things!

Some fish farms raise species that are actually clear out pollutants from the water. Bivalves (oysters, mussels, etc.) are filter feeders and cleanse their aquatic habitat! Also, tilapia are herbivores and do not require as much input as the carnivorous farmed fish need.

D.C. embraces giant quahogs!

A few days ago the Washington Post announced that the National Zoo in Washington, D.C. is now home to 10 giant clams of the species Tridacna crocea. You may think the National Zoo is a peculiar place for clams especially since the National Aquarium now has a branch in D.C., however the clams are suitably placed in the invertebrate exhibit and I highly recommend you spend time there if you ever make it to the National Zoo. It is one of the quieter exhibits, housed in air conditioning (what’s not to love about that?), and has an exhibit for chambered nautilus, a BCS species favorite.

With all that being said, it seems as though if you want to learn about T. crocea, smallest of all the giant clams species, you’ll have to come to D.C. (or simply read the article in the Post linked above)!

So, I am going to take this opportunity to brief you on a real giant clam. This posts features the largest and most elaborately colored of all the giant clam species, Tridacna gigas (pictured right). This being the largest of all living bivalves, T. gigas holds it own at a whooping 500 lbs, 3 ft 10 in length and 30 in wide. The average male American black bear is about that size. At 500 lbs, it’s no wonder they cannot shut their two shells together (It’s like when I to pack for a weekend vacation).

These hermaphrodites, found in the Indo-Pacific, are planktonic when young and sessile as adults. The diet of these placid creatures is algae as they are filter feeders.

There is concern among conservationists that T. gigas is being exploited as they are harvested for food (a delicacy in Japan) and is a popular acquisition in the aquarium trade.

I wonder what creature would win if pitted against each other: the giant clam, T. gigas, or the largest sea urchin, Sperosoma giganteum? Maybe that deserves further thought in a future post.
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