Wordless Wednesday | Limulus Love

 

LLSunsetFor more images from Beach Chair Scientist, please visit Flickr.

The short and sweet of horseshoe crab spawning

You may have heard about the phenomena of horseshoe crab spawning … but, do you really know what’s going on? It’s when hundreds of thousands of these ancient arthropods (dating back 400 million years!) make the journey to low-energy sandy beaches along the Atlantic coast, predominately along the Mid-Atlantic region (highest concentration found along the Delaware Bay), around the time of the full and new moons of May and early June to spawn. Here’s the distilled version of the horseshoe crab spawning saga complete with the words you need to know (i.e., “pedipalps” and “satellite” male) if you want to be considered a horseshoe crab expert. Who doesn’t?

https://www.flickr.com/photos/beachchairscientist/

https://www.flickr.com/photos/beachchairscientist/

  1. Journeying from intertidal and deeper waters, male horseshoe crabs arrive near the beach waiting for females.
  2. As the females come closer to shore, males attach to the female’s abdomen. The extra claw, or “pedipalps”, is what the male uses to attach itself to the females.
  3. Not just the one … but, many “satellite” males follow the conjoined pair.
  4. The females dig a depression about 5 to 30 centimeters deep in the upper part of the beach and deposit the clusters of eggs.
  5. External fertilization occurs – Allows for a little extra competition from the “satellite” males!
  6. Repeat steps 1 through 5 multiple times per season, laying 3,650 to 4,000 eggs in a cluster (usually an estimated 88,000 eggs annually!).
  7. In 2 to 4 weeks after fertilization, planktonic larvae hatch from the eggs. Some slow moving larvae may even winter within the nests and hatch out the following spring.
  8. After hatching, larvae swim for about six days before they relax in shallow waters to molt into their first juvenile stage in approximately 20 days.
  9. For the first two to three years of life horseshoe crabs molt many times over, growing a quarter of their size each time. Once sexual maturity is reached they slowdown their molting to once per year.
  10. Horseshoe crabs mature around 10 years of age (or 17 molts) and are known to live to be approximately 20 years of age.

For more information on horseshoe crabs and “99 reasons I am in Limulus Love” check out my horseshoe crab page here.

From USFWS “Miracle Migration: The Long Distance Flyer, Rufa Red Knot”

Thank you to the Northeast Office of the US Fish and Wildlife Service for posting this graphic on their Twitter feed! With the mention of horseshoe crabs, how could I not repost this!?!

  • Did you know that shorebird hunting in the Caribbean and South America may contribute to the red knot’s decline along the Atlantic coast? (OK, how can we get this practice to stop trending? Those poor little birds!)
  • With scientific management measures now in place, horseshoe crab harvest is no longer consider a threat to the red knot?
  • Habitat loss due to sea level rise, shoreline development, and human development are still consider threats to the red knot?
  • One banded red knot, B95, was nicknamed “Moonbird” because researchers discovered this bird had flown enough miles to get to the moon and back!
via @USFWSNortheast

via @USFWSNortheast

 

What are the names of juvenile coastal and marine animals?

Well, it’s been quite some time since I’ve posted and it’s all due to an adorable little distraction – my son was born in early January. The addition has been wonderful and fairly stress free (keep your fingers crossed!). In fact, I have to say this time around my biggest stress was picking out a name. We had a boy name chosen, but not a girl name, so the decision was easy. However, it got me thinking about what juvenile marine animals are called. Here is a list of ‘baby’ names of over 25 well-known ocean animals. After all, you don’t accidentally want to refer to a juvenile shark as a calf or a juvenile eel as a spet, do you? If you can expand or elaborate on the list feel free to share in the comments box.

Birds
Flamingo, gull, heron, penguin: Chick
Crane:  Chick or craneling
Pelican: Nestling

Fish
Barracuda: Spet
Cod: Codling, hake, sprag, or sprat
Eel: Elver
Most fish: Fry or fingerling
Salmon: Smelt

Invertebrates
Blue crab: Larva
Clam: Larva, chiton, or littleneck
Horseshoe crab: Larva
Jellyfish: Ephyrae
Oyster: Spat
Sand dollar, sea urchin, sea star: Larva or pluteus (free-swimming stage)

Marine mammals
Dolphin, manatee, porpoise, whale: Calf
Otter: Whelp or pup
Shark, seal, sea lion: Pup
Walrus: Cub or pup

Reptile
Turtle: Hatchling

What this short video for some cute pictures of featured juvenile coastal and marine animals. Which one is your favorite?

Juvenile Animal Names from Beach Chair Scientist on Vimeo.

For more information:
http://www.pawnation.com/2013/11/19/baby-animal-names/7
http://www.defenders.org/sites/default/files/publications/sea_otter_faqs.pdf
http://www.zooborns.com/zooborns/baby-animal-names.html
http://www.enchantedlearning.com/subjects/animals/Animalbabies.shtml
http://www.english-for-students.com/Names-of-Baby-Animals.html
http://www.pawnation.com/2013/11/19/baby-animal-names/7
http://dictionary.reference.com/writing/styleguide/animal.html
http://www.horseshoecrab.org/info/lifecycle.html
http://www.bluecrab.info/lifecycle.html
http://www.jellywatch.org/blooms/facts

Horseshoe Crab Round Up: May 2013

And, we’re concluding the first month of the horseshoe crab mating season for 2013. Over the past couple of weeks, many articles have come through the great worldwide web including some new creative introductions on the relationship of Limulus polyphemus and shorebirds, captivating expose on the capture of two horseshoe crab poachers, updates on the plight of the species after Hurricane Sandy, the discovery of a new bait that could reduce the horseshoe crab harvest, and even a information on raising awareness of the role horseshoe crabs since they play a role with QC endotoxin detection tests (but, read more to see that there may be a sustainable alternative). If you have anything other interesting reads for May please post a comment below.

Limulus polyphemus and Shorebirds (including efforts on tagging, etc)
Journey of shorebirds, horseshoe crabs to shore linked through the ages – May 1, 2013
Protecting ancient undersea creatures – May 9, 2013
Being ‘crabby’ might benefit mankind – May 10, 2013
Tagged Horseshoe Crabs at Big Egg Marsh Queens NY… – May 25, 2013
Shorebirds, Horseshoe Crabs and Stewards… – May 26, 2013
Volunteers help tag mating horseshoe crabs on Harbor Island – May 28, 2013

 

The Poaching Adventure
2 arrested for poaching horseshoe crabs from NY – May 28, 2013
It’s Dark, but We See You: Release the Horseshoe Crabs – May 28, 2013
NYPD Busts Horseshoe Crabs Poachers After Chopper Chase – May 29, 2013

After Hurricane Sandy Habitat Restoration
Restoring hurricane-damaged horseshoe crab spawning beaches on Delaware Bay – May 11, 2013
Workers race nature to rebuild Shore habitats before mating, migration season – May 20, 2013
After Sandy, a race against time to save an endangered shorebird – May 25, 2013

New Bait Alternative for Eel and Whelk
New bait may cut horseshoe crab bait use – May 30, 2013
New artificial bait could reduce number of horseshoe crabs used to catch eel, whelk – May 30, 2013

QC Endotoxin Detection Tests
Lonza Not ‘Shellfish’ When it Comes to Endotoxin QC Testing – May 21, 2013

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

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.

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.

 

10 tips for a successful beachcombing trip

It’s my favorite time of year. This is the best time to explore the beach. It’s still sunny and warm, there are frequent storms (you’ll see why that matters later), and there are few people on the beach. For another six weeks along the mid-Atlantic (before it gets too cold), I encourage you to spend some time getting to know your local shoreline. Here are 10 tips for a successful beachcombing trip.

10. What to bring. Here is a list of some items you may want to remember so you’re prepared for any situation.

  • Often the beach is considerably cooler than inland so bring layers. You may want to wear hiking pants and bring a zippered sweatshirt so you’re equipped with lots of pockets for some other items that might be essential.
  • Make sure to have some appropriate soles. Sure it’s our instinct to be barefoot, however if you want to venture out along the jetties or rocks make sure you have some old sneakers or those water shoes with some decent grip (After all, you don’t want to ruin your adventure with a puncture to some sharp object). Also, the water might be a little cooler than you’d prefer and some good foot cover will allow you to wade into a tide pool.
  • Make sure to have a watch.
  • Even during the off-season the sun is shining and is strong enough to give you a burn. Make sure to bring along a hat, sunglasses, and sunscreen.
  • It’s always a good idea to bring a shovel, grabber sick, or even a metal detector so you can gently investigate inside crevices and below the sand.
  • You are going to want to cherish the moments so find that camera and try to make a neck strap so it’s always handy. You can take pictures of items you find and want to learn about later. You’ll also want to catalog those smiles in the sun.
  • Take along a small (i.e., not heavy) identification book so you can learn more about what you find while on your outing.

9. Be hands free. One more item that you’re going to love me for suggesting is a backpack. This way you can investigate a little bit further from your base and your items are quickly at your disposal.

8. Leave important items behind. Don’t ruin the day by losing a credit card or your phone. If you’re active and in the moment you might lose something and it’s going to be difficult to retrace your steps. I won’t say “I told you so”. On the same note it’s important to leave animals, plants, rocks, and seashells where you find them. If you want to have a little bit of the beach in your home check out these great books by Josie Iselin.

7. When to go. To get the optimum experience for beachcombing you’ll want to check on when low tide is at your beach spot. The best time to go beachcombing is 2-3 hours prior to low tide or an hour or so after (This is why a watch is important, you don’t want to get stuck on  shoal during high tide). Many intertidal animals live under the water in the sand during high tide, but come out to play (and seek out food) during low tide. If you can time it so you get to check out the beach after a big storm you’ll be in for a real treat. The strong wind and wave action of storms will wash up a fossils, bones, seaweed, and lot of other interesting treasures from the ocean floor. Also, keep in mind that dawn and dusk are difficult times to identify beach treasures. Although this is a great time to spot birds as many fish tend to come up to the surface at these times.

6. Where to go. My favorite spot to beachcomb is the Stone Harbor Point in NJ, but it’s not always easy for me to get there these days. I like to remind myself from time to time that I don’t need an ocean to beachcomb. There is a lake and creek in my neighborhood and these spots are a great place to spend the afternoon. After all, these waterways eventually lead to the ocean.  No matter where I decide to spend some time beachcombing I always make sure to note the general water quality.

5. Be careful. This is just a reminder to not tamper with obviously dangerous items. Fish hooks, metal canisters, and needles often wash up on the beach. While I am going to also suggest doing your part and picking up marine debris it’s also a good idea to err on the side of caution and when poking around. Also, some rocks look very steady but it’s important to be aware of your surroundings. If you are feeling like having an adventurous day it’s might be a good idea to make sure you have someone else with you. One last thing about being careful,even though the dunes might look like an interesting place to check out – it’s important to know that those grasses are incredibly brittle and can crack easily. It’s also against the law to walk on the dunes. The dunes are an important part of the beach ecosystem as they protect our homes from storm surge.

4. Leave it be. Each rock that you turn over is part of an ecosystem. A rock might be an essential part of an animal’s home as it helps pool water during high tide. Rocks also protect them from predator as well as the sun. It’s important to always remember to not take animals out of their natural setting – especially if you see them in a tide pool. Many animals are naturally attached to rocks for survival and you could be risking their survival.

3. Play. You might not want to go home, but you also might be in the company of some people that just don’t have a very long attention span. Even more frustrating is repeating the phrase, “No, you cannot go in the water today” over and over again. Build a sandcastle. Look to the horizon for dolphins or porpoises. Make a sand angel. Look up to the sky for cloud animals. Check out my ebook for other beachcombing adventures.

Image (c) Marine Debris Tracker

2. Bag it and track it. It’s always nice to be prepared to be able to do your part. I prefer to take along a hefty canvas bag that can fit in a backpack so I can tote marine debris back to a garbage can. You might even try to acquire one of these nifty bags with holes for sand to percolate through from the Green Bag Lady. When you head back to the car you can even do some citizen science and log your marine debris on the Marine Debris Tracker.

1. Don’t expect too much. It’s important to remember to relax and respect the area you are exploring. All of the ideas above are simply suggestions and ideas to ensure you get the most out of  a beachcombing adventure. Please don’t hesitate to share your favorite stories, spots, and other ideas for a great day. You can comment below of email me at info@beachchairscientist.com.