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

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.

Finned foliage

I wanted to share this image of anthias swimming in the Red Sea to usher in the briskness of autumn! As you know it’s my favorite time to beachcomb, but it’s also my favorite time to be surrounded by the brilliant-colored leaves of trees. The reds, yellows, and oranges are as vibrant as a coral reef

These schooling anthias are interesting because they are born one sex, but then change to another. In fact, all anthias are born female and only change to male if the male in their school dies. Most anthias remain female their entire life. This type of hermaphrodite is known as protogynous (proh-TAH-guh-nus). If it were the other way (beginning their life as male and changing to female) it would be known as protandrous (pro–TAN-dur-us).

RedseaAnthiasThe image is from Free Underwater Images, a new favorite resource. This website “promotes increased awareness of the marine environment by allowing users to download free, high quality underwater photos.  All images are in the public domain and free for any use without prior written permission and without fee or obligation. Images can be used for any non commercial purpose”.

A quick lesson in wetland ecology

May is National Wetlands Month, so what better time to get creative in sharing how much I appreciate wetlands? Here is a new graphic with an overview of 1) four main types of wetlands and 2) why wetlands are important.

Wetlands are important because they:

… reduce damage from floods.
… protect land from storm surges.
… improve the quality of our water.
… can sustain a wide variety of plants and animals.
… can slow shoreline erosion.
… can provide vital food for many commercial & recreational fisheries.
… may provide a sustainable source of valuable timber.
… many rare and endangered species call them home.
… provide animals important shelter from encroaching humans.
… moderate stream flow.
… recharge groundwater supply.

Different types of wetlands:

Marshes are fed by groundwater or surface water. Marshes are dominated by soft-stemmed vegetation. Marshes are pH neutral and, therefore are abundant with plants and animals. Marshes can be freshwater or saltwater, tidal or inland. Other common names for marshes may include: prairie potholes, wet meadows, vernal ponds.

Swamps are dominated by woody-plants that can tolerate a rich, organic soil covered in standing water. This may include trees such as the cypress, cedar, or mangrove. Swamps may also be dominated by shrubs such as the buttonbush. Swamps are fed by groundwater or surface water.

Bogs are fed by precipitation and do not receive water from nearby runoff, such as streams or rivers. Bogs are dominated by a spongy peat deposit and the floor is usually covered in sphagnum moss. Bogs have acidic water and are low in nutrients making them a difficult place for plants to thrive.

Fens are peat-forming wetlands and are fed by nearby drainage such as streams or rivers. Fens are high in nutrients with low acidic water. Fens are characterized by grasses, wildflowers, and sedges. Often parallel fens adjacent to one another will eventually create a bog.

For more information about anything in this post or in general about wetlands please check out this overview by the EPA or email info@beachchairscientist.com.

What is oceanography?

If you take biology, physics, meteorology, chemistry, geology, geography and mix them all together (via the same concept as Ekman transport) you come up with oceanography. See this very concise infographic from the Sea Blog for a visual depiction of how it all comes together. Click here to understand the difference between a marine biologist and an oceanographer.

What eats sea urchins? Revisited

Sea UrchinBack in 2008 we brought you some information on what eats sea urchins. After all, it is hard to imagine anything being able to enjoy the spiny echinoderms. Here is an interactive game (you must have Flash) produced by Stanford University that takes it one step further. Try to place which animals and/or plants are eaten by the sea urchin (prey), which animals eat the sea urchin (predator), and which animals and/or plants may not have a relationship with the sea urchin. You see some great similarities of the animals that eat the sea urchin! Come back here and share what you discover after playing the game. Enjoy!

13 apps for your day at the beach

It’s time to get the most out of that last trip to the beach!

Whether you’re ready for a day out on the boat, lounging, beachcombing, catching some waves, or preparing a feast there is an app to get you more involved in your marine environment. Apps are not only a great way to learn something new on the fly but can be a useful tool for engaging one another in settings where you may not have common ground. (OK, at the very least apps settle many ‘discussions’.)

Here is a list of useful and rather attractive apps that can connect you to your inner marine biologist.

AUDUBON FIELD GUIDES: Audubon Fishes of the Caribbean and the Gulf of Mexico and Audubon Fishes – A Guide to North American Fishes include photos, geographic ranges, and concise yet detailed descriptions of appearances. Coming soon is the field guide for the Mid-Atlantic shoreline. ($9.99)

OCEANOGRAPHY STUDY GUIDE: If you are into fun oceanography trivia and want to learn more about the geography of the sea than download this app. It isn’t an endless list of “did you know?” facts but rather a large range of topics with well written articles for the serious beach chair scientist. ($4.99)

OFFICIAL APP OF ISSF: The International Seafood Sustainability Foundation (ISSF) was founded in 2008 when leaders of industry, scientists and environmental champions voiced concern over the future of tuna fisheries. This app provides a glossary of terms, videos, and a list of the status of stocks. (Free)

SEA TURTLE APP: This app was created by the Sea Turtle Conservancy and allows you to follow read the latest on sea turtle news but much more exciting you can track the global migration of different sea turtles with interactive satellite tracking maps! (Free)

Enough sitting around – it’s time to get out there and do something:

MOBILE APP FOR IGFA: The International Game Fishing Association created an app for weigh station locations, angler rules and regulations, customizable quests, and advice for trip planning. What more does a sport fisherman need?

MARINE DEBRIS TRACKER APP: This collaboration is brought to you by the Southeast Atlantic Marine Debris Initiative. The reporting of where you find marine debris can help to focus and prioritize federal efforts. The app uses GPS and allows you minimal work of sorting through lists of common marine debris. (Free)

CRAB APP: This app is an offshoot from the marine wild lab and allows you to collect horseshoe crab species data that will be used in scientific research. Horseshoe crabs are of enormous importance to 1) the drug industry due to their blood, 2) to fisheries for bait, and 3) to migratory shorebirds for its eggs.  (Free)

TIDE GRAPH: I found out that there are many, many apps out there to help you monitor the tides. Tide Graph will work for both coasts in the US and provides graphs to help you see how the tide changes over the day and the month. ($1.99)

If you are preparing a feast or gorging on some dockside seafood:

SEAFOOD WATCH: For years the Monterey Bay Aquarium has produced adorable pocket-sized regional cheat sheets so you can get a quick overview of what species are considered over fished or not in your neck of the woods. They continue to produce this application for your iPhone and use GPS tracking to discover where you are so you can get the most relevant information. (Free)

PROJECT FISHMAP: Monterey Bay Aquarium also gets you more involved by asking you to submit information when you find a restaurant or market that advocates sustainable seafood. As the map grows you can see what spots you’ve not uncovered in your neighborhood. (Free)

FISHPHONE APP: With one quick text (example: “fish salmon”) to 30644 Blue Ocean Institute will fed you intel on your species of choice. For instance, they’ll rank the sustainability and toxicity levels and send an overview of its conservation status. (Free)

SAFE SEAFOOD: This app takes information from ten different seafood rankings (including Monterey Bay Aquarium and the Environmental Defense Fund) to create its list. The app outlines choices in an easy to review “best to worst” list. I particularly like that fish with multiple different market names are listed by each of common name too. ($0.99, but 10% of the proceeds go to EDF)

I am certain I missed many wonderful apps. Please do not hesitate to email at info@beachchairscientist.com to share!

Added October 27, 2011: An app for water quality and to get the most up-to-date grade for your beach presented by Heal the Bay in California.

Where is the coral triangle?

After some research I scored a wonderful description of where the world’s most ecologically diverse  marine ecosystem lies. Spanning over six countries this 6 million kilometers squared coral triangle is significant because it is home to six of the seven species of sea turtles. This infographic, produced by World Wildlife Fund, gives a rundown of the protection status of each the sea turtle species as well as a wealth of other great information. For instance, did you know …

… 3000 leatherback sea turtles nested along the coast of Terengganu, Malaysia in 1960? In 2000, according to data from Dr. Chen Eng Heng with the Department of Fisheries in Malaysia, there were none.

… 90% of sea turtle hatchlings never make it to their first birthday.

Take a closer look at the infographic to learn more. Lastly, don’t forget May 23rd is International Turtle Day!

Test your knowledge: National Ocean Science Bowl biology

Here are some more sample questions from the Consortium for Ocean Leadership‘s popular National Ocean Science Bowl (NOSB). These questions come from the Biology section.

Good luck!

1) Northern elephant seals come ashore during the spring and summer to do what? a) Mate b) Eat c) Give birth d) Shed their fur

2) The habitat of blue whales, tunas and swordfishes is best described as: a) Benthic b) Littoral c) Estuarine d) Pelagic

3) Intensive aquaculture of which of the following organisms has contributed to loss of mangroves around the world? a) Tilapia b) Cod c) Salmon d) Shrimp

4) Lophelia (LO-fee-lee-ua) coral reefs in the North Atlantic are being primarily damaged by: a) Pfiesteria b) Poisoning c) Rising temperatures d) Trawling

How to win a game of Survivor if stranded on a beach

DewberriesWhile I am not here to tell you how to form alliances, I can mention some edible seaside plants found along the Atlantic coast. These include: Sea rocket, sea lettuce, prickly pear, bull thistle, dewberry and winged sumac. You can eat the blackberries of the dewberry with milk and honey. For a refreshingly cool drink soak winged sumac in cool water for 15 minutes. Devour the sweet pulp of the prickly pear after you peel away the skin. Add the leaves of sea rocket and sea lettuce to a fresh seaside salad. Lastly, gorge on the stems of the bull thistle (of course, only after you’ve removed the thorns!).

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