99 reasons I’m in ‘Limulus Love’

It’s no secret that I love those horseshoe crabs. Well someone on Twitter this week asked me why I am so crazy over them so I thought I’d take the time to outline 99 reasons I think Limulus polyphemus are a fascinating species.

  1. Three Nobel Prizes were awarded to scientists who did some or all of their research using horseshoe crab physiology.
  2. As far as the horseshoe crab’s Latin name translation, Limulus mean ‘askew’ and polyphemus is taken from a one-eyed giant in Greek mythology.
  3. The very intriguing name of Xiphosura (Greek ‘Xiphos’ meaning sword and ‘ura’ meaning tail) was given to the order of the Atlantic horseshoe crab and its three closest living related species.anatomyhsc
  4. There are 4 living species of horseshoe crabs and only one of those inhabits the western Atlantic waters – the Atlantic horseshoe crab. The other three are found in the Pacific Ocean.
  5. Samurai warrior helmets were modeled after the prosoma of a horseshoe crab.
  6. The body of a horseshoe crab (top picture) is divided into three parts – the prosoma, opisthosoma and telson (tail).
  7. Horseshoe crabs tend to be no more than 7-14” across.
  8. There once was a 50 foot long, 113,000 pound artificial reef horseshoe crab off the coast of NJ.
  9. Takeshi Yamada (pictured 3rd down) is a world-renowned artist often creating masterpieces using horseshoe crab molts.
  10. Horseshoe crabs have remained fairly unchanged over the past 300 million years (that’s 100 million years before there were dinosaurs on earth!).
  11. Horseshoe crabs are the perfect representative for Darwin’s theory that ‘the most adaptable species will prevail’.
  12. Horseshoe crabs are one of the world’s oldest animals.
  13. Before the last ice age, horseshoe crabs didn’t live much farther north than Florida.
  14. Scientists believe that horseshoe crabs (even perhaps many different species of them) were among the most dominant of animals 300 million years ago.
  15. Horseshoe crabs used to be called ‘horsefoot crabs‘ because their shell was thought to resemble a horse hoof.bcs_limuluslove
  16. Horseshoe crabs are sometimes referred to as a ‘living fossil’.
  17. Adult horseshoe crabs are often referred to as ‘walking museums’.
  18. While horseshoe crabs are opportunistic feeders, they are not aggressive animals!
  19. Most people do not understand the value of horseshoe crabs.
  20. People have organized workshops to understand bait alternatives for using horseshoe crabs to catch eels and conch.
  21. Horseshoe crabs are “the single most-studied invertebrate animal in the world”.
  22. While a horseshoe crab’s telson (tail) helps to create the appearance for an intimidating animal, they are not dangerous animals!
  23. Horseshoe crabs are so misleading – they’re actually more closely related to scorpions and spiders than crabs!
  24. Horseshoe crabs do not have mandibles, antennae, or pincers like true crabs.
  25. Native Americans ate horseshoe crab meat, used the shell to bail water, and used the tail as a spear tip.
  26. A juvenile horseshoe crab is easily identifiable because they look just like adults (see 4th picture down).
  27. Horseshoe crabs molt, or as naturalist Samuel Lockwood stated, “it is spewing itself from its own mouth”.
  28. Horseshoe crab molts are excellent shelter for mud crabs, sand shrimp, and spider crabs.
  29. A female’s lucky number is 17. That’s how many times they’ve molted before they’re ready to mate.
  30. As a horseshoe crab gets older and molts more often, they venture into deeper waters.
  31. Each time a horseshoe crab molts they grow an average on 25%.
  32. A horseshoe crab exoskeleton is made up of chitin – a material with wound healing properties.
  33. Horseshoe crabs spend most of their lives hidden.
  34. At the turn of the 19th century, horseshoe crabs were valued as a fertilizer, particularly for poultry, corn, and tomatoes.
  35. Today fishermen use horseshoe crabs as bait to catch eels and whelk.
  36. The threatened loggerhead sea turtle feasts on adult horseshoe crabs.
  37. American eel, killifish, silversides, summer flounder, and winter flounder rely on horseshoe crabs eggs and larvae for food.
  38. Horseshoe crab eggs are green.
  39. Horseshoe crab eggs are rich in fat and protein.
  40. Horseshoe crabs are big midnight snackers and love to feast on worms and mollusks.Horseshoe-crab-eggs-larvae-visible
  41. The mouth of the horseshoe crab will tickle your fingers if you’re lucky enough to have a job where you get to show people how they eat.
  42. Horseshoe crabs use their legs to chew up food and guide food into their mouths right in between their legs.
  43. Horseshoe crab legs are so strong they can crush a clam.
  44. Horseshoe crabs are expert javelinists – using their telson (tail) to act as a rudder and right itself when it tips over.
  45. The 13 pairs of horseshoe crab appendages are very multipurpose – using them for locomotion. burrowing, food gathering, and/or water flow.
  46. Horseshoe crabs use their dozen legs to swim upside down in the open ocean.
  47. Horseshoe crabs (predictably) participate in an annual orgy each May and June when thousands descend on the eastern Atlantic coastline to spawn (see fourth image down).
  48. Horseshoe crabs have a ritual of spawning during high tides of the new and full moons in May and June.
  49. Horseshoe crabs reach sexual maturity around the ages of 9-12.
  50. Horseshoe crabs tend to live a long time, usually 10 years or so after they’ve sexually matured.
  51. If horseshoe crabs can keep their gills moderately damp their survive to the next high tide in case they were to get hsc_orgystranded.
  52. Horseshoe crabs are great vessels for other animals.
  53. The highest concentration of horseshoe crab spawning on the Atlantic coast takes places along the Delaware Bay.
  54. Approximately 10 horseshoe crabs will survive to adulthood from each of the 90,000 eggs a female lays during her spawning cycle.
  55. A female horseshoe crab will lay almost 20 clutches of eggs each season.
  56. It’s a community effort making certain the eggs get fertilized. Often times many males with aggregate to a female (the males not attached are known as ‘satellite’ males.
  57. In adult males, the second pair of claws (having a distinguishable “boxing-glove” appearance) are used to grasp females during spawning.
  58. If it wasn’t for horseshoe crab eggs, many migratory shorebirds wouldn’t be able to survive.
  59. Many think there is a link between the decline in shorebird populations and horseshoe crab over-harvesting.
  60. The four most abundant species of shorebirds (relying on horseshoe crab eggs) along the Delaware Bay shore are the red knot, ruddy turnstone, semipalmated sandpipers, and sanderlings.
  61. Almost 50% of the red knot population uses Delaware Bay as mid-point stopover to consume thousands of horseshoe crab eggs. These robin-sized birds impressively travel from southern Argentina to the Canadian high Arctic to breed.
  62. The horseshoe crab-shorebird phenomenon helps to generate a large portion of the $522 million  annual ecotourism industry in Cape May County, NJ.satmenhsc
  63. The world’s leading authority of horseshoe crabs is Dr. Carl N. Shuster, Jr.
  64. In March of 2001, NOAA Fisheries Service established the Dr. Carl N. Shuster, Jr. Horseshoe Crab Sanctuary in federal waters off of the  Delaware Bay.
  65. Horseshoe crab blood is blue (see 7th picture down).
  66. Horseshoe crab blood is blue because it contains copper-based hemocyanin to distribute oxygen throughout their bodies (We use an iron-based hemoglobin to move oxygen around).
  67. Horseshoe crabs are essential to biotechnology.
  68. Horseshoe crabs are one of the pioneers in using marine organisms to save human lives.
  69. Horseshoe crabs are what we have to thank for our flu shots.
  70. Horseshoe crabs are sometimes referred to as ‘man’s best friend’.
  71. Horseshoe crabs are often captured to have their blood drained, all in the name of science.
  72. Horseshoe crabs can be released after they have their blood drained.
  73. Horseshoe crab blood cells (amoebocytes) congeal and attach to harmful toxins produced by some types of gram negative bacterias.
  74. Limulus Amoebocyte Lysate (LAL) is the name of the clotting agent made using their blood to detect microbial pathogens in medical intravenous fluids, injectable drugs, and supplies.
  75. The global market for LAL is approximately $50 million per year.
  76. The adaptation for the ability of the horseshoe crab’s blood to congeal in the presence of either living or dead gram negative bacteria has never been able to be reproduced.
  77. Horseshoe crabs have used in the development of wound dressings and surgical sutures.
  78. Horseshoe crabs have a body shape that poses difficulty for predators.wireddotcom_drainblueblood
  79. Horseshoe crabs have ten eyes.
  80. The vision of a horseshoe crab is equally as impressive at night as it is during the day with the use of their lateral eyes.
  81. With a pair of compound eyes, each with 1,000 black disks, horseshoe crabs can see to each side, ahead, behind, and above.
  82. Scientists have learned quite a bit about how human eyes function from research with cells found in horseshoe crab eyes.
  83. Horseshoe crabs have a lateral inhibition mechanism using their eyes which allows them to distinguish mates in murky water.
  84. Horseshoe crabs need a book to breathe, that is – ‘book gills‘ to be more specific.
  85. Horseshoe crab gills have small flaps resembling the pages of a book.
  86. Horseshoe crabs tell time with their tail.
  87. Horseshoe crabs have a heart that cannot beat on its own.
  88. Horseshoe crabs eat through their brain.
  89. Horseshoe crabs chase females that run away!
  90. The black disks, also known as ‘ommatidia‘, found in the compound eyes of the horseshoe crab are the largest known retinal receptors in the animal kingdom.
  91. Horseshoe crabs are able to adapt to vast changes in salinity (i.e., they’re euryhaline).
  92. Horseshoe crabs are able to adapt to vast changes in oxygen availability (i.e., they’re euryoxic).
  93. Tracking juvenile horseshoe crabs with your eyes can be a great way to spend time at the beach.hsceyecloseup
  94. You can also track horseshoe crabs and other wildlife with your iPhone while at the beach.
  95. You can get involved in helping stranded horseshoe crabs and ‘Just flip ‘em’ (see last picture).
  96. If you are a classroom teacher in Maryland you can raise horseshoe crabs as a way to increase student’s ocean literacy.
  97. Monitoring programs, like this one in Long Island Sound, are helping to advance the understanding of horseshoe crabs and their impact on humans.
  98. Development, pollution, water quality, and over harvesting have impaired the horseshoe crab’s habitat.
  99. Today and in the future we have the chance to protect horseshoe crab populations at a sustainable level for ecological and commercial uses.smilowitz

The world’s horseshoe crab research finally finds a home

This month the Ecological Research & Development Group (ERDG) released a one-stop-shop for research, conservation, and education initiatives on the world’s four species of horseshoe crabs. This was a result of the discussions from the 2011 International Workshop of the Science and Conservation of the Asian Horseshoe Crabs held in Hong Kong.

Be sure to check it out today. There’s lesson plans, peer-reviewed articles, posters, PowerPoint presentations, and more. It’s the intention of the database to serve as a tool to benefit everyone who is in Limulus Love!

I was surprised to learn that the new database includes over 2,000 citations and ERDG is still looking for more materials from people like you and me (Maybe, I’ll submit my cheesy infographic).

Horseshoe Crab Research Database http://horseshoecrab.org/research/

Horseshoe Crab Research Database created by the Ecological Research & Development Group

Share your love of the ocean with these unique and inspiring gifts

With less than two weeks before the big ‘gift-o-rama’ day, it’s time to hunker down and get those gifts in time for wrapping and shipping (after all, shipping ground is a lot less harmful for the environment than air). Here’s a list of gift ideas that will inspire anyone on your list to follow your lead to take an active role in loving and learning about the ocean.

1. Beach Amazonite necklace from Peace of Mind on Etsy: It’s a piece to be treasured with a sweet little charm that hangs  on an 18″ sterling silver ball chain with a lobster style clasp. Also, $10 from the sale of each necklace will be donated to the Whale and Dolphin Conservation Society.
2. Cutting board from Waypoint (pictured): Avalon_CB-250x250This sturdy piece features the coordinates of ‘where you want to be’ and is made of solid maple and mahogany. It makes an interesting decoration or is perfect for serving appetizers. The double cleat board features two stainless steel 5” Herrschoff nautical cleats and measures approximately 8″ x 20″. This classic piece was a big hit as a recent gift for my father-in-law who has a cottage in Falmouth, UK. Made in the USA.
3. Driftwood hat or coat rack from nestibles on Etsy: Check out this sturdy, repurposed, shabby chic hook set for your entryway. The wood was collected from Long Island Sound and was sanded with a yellow paint wash.
4. Horseshoe crab pillow from Outer Banks Trading Group: It’s a hand sewn 14″ x 24″ pillow printed with environmentally friendly pigment ink on an organic cotton/hemp blend with a knife edge. Made in the USA.
5. Marine rope doormat from Gaiam: This durable doormat, made from reclaimed lobster trap float ropes, is resistant to mildew and indestructible. It’s 33” x 20½”  and is available with the options of black/teal and blue/green, although they vary because the availability is based upon the float ropes traded in by the Maine lobstermen.
6. Messenger bag from United By Blue: This bag is perfect for any beach adventure. It’s made of 100% organic cotton and United By Blue removes 1 pound of trash from our oceans and waterways around the world for every item sold.
7. Salts of the world from Uncommon Goods: Six varieties of exotic salts for presentation or cooking. It’s set in a groovy and stylish rack made of reclaimed cedar. The salts are from around the world but the tubes are made in the USA.
8. Tumblers from Tervis: These sturdy insulated cups keep hot drinks hot and cold drinks cold by harnessing air and sport all sorts of designs from the Maryland blue crab to your alma mater. Made in the USA.

Check out these fun finds for the kids:

1. 10 Little Rubber Ducks by Eric Carle
2. Lionfish puzzle from Fat Brain Toys
3. Sea life bath puzzle from Abe’s Market
4. Sea plane from Green Toys

These are just some ideas if you’re sitting at your desk shopping. But, why not get out there are check out the gift shop at your local nature center?

It’s a happy holidays giveaway

Horseshoe Crabs and Velvet Worms by Richard Fortey

Horseshoe Crabs and Velvet Worms by Richard Fortey

Let your heart be light … It’s officially the holiday season! I am seeing twinkling lights throughout the neighborhood, trees trimmed in the window, and I seem to be baking up a storm.

It’s also my favorite time of year to tell those around me how much I appreciate them. If you read this blog, ‘like’ Beach Chair Scientist on Facebook, or ‘follow’ Beach Chair Scientist on Twitter you’re certainly keeping me going and I am very grateful for your support. It’s been a fantastic adventure answering your questions and creating entertaining and educational answers. Also, it’s such a pleasure each time I (virtually) meet new people that continually inspire me.

From now until the end of Wednesday, December 12th I’ll throw your name into another giveaway to win a copy of the New York Times best seller, Horseshoe Crabs and Velvet Worms by Richard Fortey, if you 1) comment on any post here or 2) comment on any post on Facebook or 3) retweet any content on Twitter (@bcsanswers). Each time you comment or retweet will be another chance to win. The book is an incredible gift for the natural history buff on your list or even for yourself!

Update (12/13/2012): Thanks to Random Picker for helping make the raffle so efficient! The winner of Horseshoe Crabs and Velvet Worms is a Twitter follower! Thank you to everyone that participated your support means the world!

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Do all horseshoe crabs molt?

Once a horseshoe crab reaches its full size, it stop molting. Their shells then come to host many sessile creatures, including slipper snails. Image (c) Bekki Rich.

All horseshoe crabs molt – until they reach adulthood. They grow on average a quarter of their size each time they shed. Females grow to be about two feet across and males a bit smaller. Molting occurs several times during the first few years and slows as they age. It usually takes 17 molts to reach sexual maturity  at age 9-11.

Studies have proven that adults do not molt because the age of organisms living of the crab’s shell. For instance, scientists Bottom and Ropes (1988) completed a study to determine that large slipper snails (Crepidula fornicata) were at least 8 years old on a sample of specimens. This would then make the average age of horseshoe crabs in the Delaware Bay to be 17 years old.

Also, the deteriorated carapace of some horseshoe crabs, as well as the presence of internal chitinous rods that hold the carapace in place are also evidence that older horseshoe crabs do not molt.

Well, well, ‘whelk’ what do you know?

It’s no surprise why my home state of New Jersey has been on my mind lately. Using my enthusiasm for nostalgia, I decided to investigate little known facts about the state. Today I am eager to share some at best ‘compelling’, but possibly ‘useless’ knowledge on the New Jersey’s state shell, the knobbed whelk.

Image (c) by Charles Tilford on Flickr: noncommercial use permitted with attribution / share alike.

Image (c) by Charles Tilford on Flickr:
noncommercial use permitted with attribution / share alike.

  1. Governor Christine Todd Whitman declared the knobbed whelk (Busycon carica) the state shell on April 13, 1995.
  2. In addition to being the state shell of New Jersey, the knobbed whelk is also the state shell of Georgia.
  3. The shell of the knobbed whelk is coiled and pear-like and appears anywhere from yellow to gray in adults with purple and browns tints in juveniles. Its inside is typically pink to white and iridescent.
  4. The animal that lives inside the shell is a one-footed member of the sea-snail family (specifically the family, Melongenidae).
  5. Knobbed whelks are found off the east coast of the U.S. from Massachusetts to northern Florida.
  6. The meat of the whelk (and that of the conch) is known as scungilli.
  7. Whelks have a large pair of tentacles, each with a light-sensitive eyespot.
  8. Whelks also have a small pair of tentacles that are used for smell and touch.
  9. The U.S. exports whelks (i.e., knobbed, as well as lightning) to many areas of the world including France, Southeast Asia, Australia, and the Caribbean.
  10. Horseshoe crabs are used as bait to harvest channeled or knobbed whelks.
  11. There is a popular Korean side dish known as golbaengimuchim, which is seasoned whelks with spicy sweet and sour sauce with vegetables.
  12. Knobbed whelks can be up to 12 inches long.
  13. Knobbed whelks and lightning whelks can be distinguished by the difference in their openings. Knobbed whelks are dextral (i.e. right-handed).
  14. Knobbed whelks and lightning whelks lay strings of egg capsules.
  15. Knobbed whelks feast on clams using a radula.

What happens if the tide leaves a horseshoe crab stranded?

HSC_BCS

It’s not often you stumble across this on the beach. I asked horseshoe crab expert Danielle Chesky, Fishery Management Plan Coordinator with the Atlantic States Marine Fisheries Commission, what was happening in this picture and she said that “they’re dug in for the day after spawning until the high tide comes and they can get back out to sea”. For more posts on horseshoe crabs check out the Limulus Love page. Thank you to a colleague’s in-laws for sending along this picture.

 

How to track a horseshoe crab

Today I am excited to bring a new video produced by Coastal Kingdom TV, a television series dedicated to sharing the unique and diverse habitats of the South Carolina lowcountry. Host Tony Mills demonstrates the best way to track horseshoe crabs in the tidal flats of South Carolina and does a superb job enlightening us on some of the animal’s unique characteristics.

Witness the horseshoe crab molting process

I’d like to share this remarkable two and a half-minute video of a horseshoe crab during the molting process. Produced by the Hong Kong Coast Watch and filmed by Kevin Laurie in May 2011, this film shows a juvenile Tachypleus tridentatus (one of the three species found in the Pacific ocean along the coast of Japan) shedding its outgrown exoskeleton at 16 times real speed. With calming music playing in the background you can witness the horseshoe crab as it burrows in the sand and exerts a tremendous amount of effort pulsing and pushing as it releases itself from its old shell. You can also get a glimpse as to the interesting creatures crawling around on the shores of the Pacific sea. For more information on the morphology differences between the four extant species of horseshoe crabs visit the Ecological Research & Development Group (ERDG), a leading resource for all things horseshoe crab related.

Why is the blood of horseshoe crabs blue?

Horseshoe crabs use hemocyanin to distribute oxygen throughout their bodies. Hemocyanin is copper-based and gives the animal its distinctive blue blood. We use an iron-based hemoglobin to move oxygen around.

The blood of this living fossil has the ability to  clot in an instance when it detects unfamiliar germs, therefore building up protective barriers to prevent potential infection. This adaptation has made the blood of the horseshoe crab quite desirable to the biochemical industry.

Image (c) wired.com