Horseshoe Crab Spawning

For the last 450 million years or so, since before there were trees, a unique organism has been throwing a party on the planet, with the biggest parties on:

New and Full Moon, in May and June

That organism is Limulus polyphemus, or the Atlantic Horseshoe Crab.  At high tide on the full moon this Friday, these crabs will take part in a dance routine choreographed by the moon and evolution:  the come ashore on the highest tide to spawn and lay their eggs in the sand.  The eggs take fourteen days to develop, and when the hatch, it will be the next new moon/full moon, and the tide will come back up to the same spot to wash the bebbies down to the sea.  

I've been fascinated by horseshoe crabs for the past six years, and have learned to sync up with their calendar of events.  These parties happen regularly, mostly out of sight of humans.  They'll happen whether you are there or not, but if you happen to get a party invite, you can come and witness a large-scale gathering of an alien species.  This is your invite.

If we're in NYC, there are modest gatherings of crabs in Jamaica bay, but if we're gonna mobilize people, let's go to the horseshoe crab epicenter on the east coast:  delaware bay.  Cape May Courthouse, a small township on the north shore of the bay, is about 2.5 hours' drive south of the city.  I'm planning to leave around 5-5:30, and get there around 7:30/8:00, with enough time to see the rising action before the peak high tide hits at 9:14.  In Delaware bay spawnings, in the span of ~2 hours, it goes from zero crabs on the beach to tens/hundreds of thousands of horseshoe crabs.  It's worth getting there early to see the contrast.

Who are you? What is this?  Hi! I'm Alex Hornstein! I'm an inventor and wildlife photographer with a specialty in marine megafauna (aka big ocean friends).  There are lots of wildlife photographers out there who buy fancy cameras and take beautiful photos, but there aren't many inventor photographers who build their own cameras to photograph wildlife in ways that no one else can.   That's what I like to do.

In addition to working with scientists, conservationists and science communicators, I spend a lot of time teaching and working with children.  I like to use the inventor part of my brain to take fancy, expensive hardware that scientists use to answer their own questions about life in the world, and turn it into something cheap & simple that a four year-old can use.  I'm interested in how we can develop individual relationships with the natural world around us, and how to use new and old techniques to explore, observe and understand what is going on in nature when we are not around.

trunkCam is a new prototype device I've been working on since ~september last year.  I designed it originally to film urban eels in Providence (ask me about urban eels!), and I found it to be a fascinating tool for filming all kinds of wildlife.  Workshops where I see how other people use it are really fun to do, and they help me make it better.  We don't really need a trunkCam to see these crabs, but I'll bring some and maybe we can get close-up looks at things that people have never seen before, like an under-the-sand view of the eggs coming out, or my favorite crab mystery: why they emit steady streams of bubbles while they are spawning underwater (see the main photo)

What to wear? The weather looks relatively nice -- 50-60F with a light breeze.  Wear layers and stuff that you don't mind getting sandy/wet.  

What to bring?  

• Bring some food and drinks!  Let's make this a spawning potluck!  I'll bring a small table and some trash bags
• closed-toe watershoes:  horseshoe crabs are harmless, but their telsons (their tails) are poky and you will be dismayed if you accidentally kick one.
• It's nighttime, so bring a flashlight.  Headlamps are particularly handy.  
• cameras -- this is real cool, you'll want to photograph it
• a towel and a change of clothes -- we may want to wade in the water if it's nice/not gross (later in the season, the amount of decaying organic matter makes the water real gross).    Even if we're just around the season
• It's helpful but not necessary to bring a smartphone.  We don't really need trunkCams to see these guys, but it is cool.  I've got a couple loaner phones, and we can put more of them into kids' hands if there are more phones around.

What not to bring?

Bug repellent.  Horseshoe crabs are biologically closer to spiders than ocean crabs, and the stuff that is designed to kill spiders can work on them.  Don't bring it/wear it!  

It won't be all that buggy at this point in the year, but bring long sleeves/pants if you're concerned.

How do I get there?

This is a field trip -- Cape May is 2.5 hours from NYC.  We're going to leave around 5-5:30, and I think we'll get back late, around 1-2am.  Sometimes the horseshoe crab party is at convenient times, other times it's in the middle of the night -- it's synced to a different celestial body than our own, and the moon does not care about your work schedule.  

IMO, this is worth a couple cups of coffee.

For logistics, I made a carpool feature -- click on the coordinate carpool button, and you can put in the size of your group, and if you want to offer spots in a vehicle, or if you need spots.  It will show you people near you who have complementary situations to you.  Feel free to text/call alex at 401.688.0489 if you want to talk it over

What age should my kid be?  Horseshoe crabs are great for children of all ages!  This will be a late night -- high tide is around 9:30pm, so plan accordingly. 

Anything I should tell my kid?  This is a spawning event, so it's a good time to pre-game with a talk about natural reproductive processes, because we will be ankle-deep in one.  Spawning is different from sex -- it's more of a spray-and-pray, probabalistic approach to reproduction rather than a one-on-one coupling.  

Also, it's worth knowing that about 10% of the horseshoe crabs tend to get exhausted during the spawning and don't make it back out to sea with the receding tide.  We can (and will) rescue them, but there will be a significant amount of new life and new death.  Talk about this with your kid.  These guys have been doing it since long before us, and dying is part of this event.  It's just good to know about that going in, especially for kids for whom death in the wild is a sensitive topic.

I'm running late!  I can't stay for the whole time!  I have LOGISTICS STRESS!  

That's cool.  This is a very chill invertebrate orgy and there is no need for logistics stress.  We are just hanging out with kids by a pond.  You can call me at 401.688.0489 if you come late and can't find us.  It's fine to leave early.

What will we see? 

We will definitely see horseshoe crabs, the only question is how many.  I have gone down twice to delaware bay for the horseshoe crab spawnings.  This spot is on the north shore of the bay, where I've never gone, but reports say tens of thousands of crabs (south shore at the peak season is about 750,000 crabs).   This is also at the very beginning of high season, so numbers will be impressive but perhaps not fully insane.  Maybe low tens of thousands.  

This album was from a spawning in delaware bay a couple years ago, and will give a sense of scale

I have tried many different ways to capture the magnitude of this event, and it is really impossible, IMO, to capture in a single image or video.  It must be experienced.  I particularly love it because it's a very clear picture of natural abundance -- even though this is only a small fragment of what the northeastern ecosystem was like, pre-settlement, it is still a striking experience where you can see just how much life is around us.

Lots of other things to see -- Red Knots are birds with one of the longest migratory path of any animal on the planet, and they are flying in right now from antarctica to delaware bay to eat the eggs the horseshoe crabs will be laying on Friday.  Lots of other animals also come out to eat the eggs -- terrapin turtles, lots of shorebirds, the odd raccoon or mouse.  You can try them, if you like.

Have you written any pop song parodies about horseshoe crab spawnings?  I'm glad you asked

animals filmed by trunkCam