What is Horseshoe Crab Blood Used For and How Do They Spawn? Meet Edna the Horseshoe Crab!

horseshoe crabs, horseshoe crabs mating

Horseshoe Crabs mating on the beach (via Wikimedia Commons)

Hi, I’m Edna, a horseshoe crab. I’m not truly a crab, but an arthropod related to scorpions, spiders and ticks. I’m excited because it is the new moon. It is time for me to mate and lay my eggs in the sand. This is a big deal to us horseshoe crabs to actually come out of the water for this special event.

It’s getting dark and the tide is high-I sense it’s time to crawl out of the water. I don’t have good vision, even though I have up to 10 eyes! Although I don’t see as well as humans, my vision is one million times better at night than in the day.

My special chemicals, or pheromones, that I release into the water attract male horseshoe crabs to me in the surf. One of them latches onto my back with a special claw. It’s almost time to lay my eggs!

I begin my climb out of the surf. Waves crash all around me until I make it to the wet sand. I climb out a little further and begin digging a hole to lay my 4,000 eggs. I dig and dig, and finally begin to deposit my eggs. The male horseshoe crab clasped to me fertilizes the eggs as they come out of me.
I finish laying my eggs in the sand, and the male detaches from me.

Wait, why am I floating in the air? What happened to the sand and water? Something has grasped me. Am I doomed?


I am in a dark place. I scramble to crawl up the wall placed before me but it’s no use. My legs just keep scratching up against something, but I can’t crawl out or over it.

Lots of other horseshoe crabs are piled around me. I sense the moonlight one moment, and the next it is gone. I thought my life might end being eaten by a shark, but surrounded by my fellow horseshoe crabs in the dark?

I am tired after laying all those eggs, so I sleep. When I wake up I am in a bright area. It’s not the warm sun, but there is light all around. I can move all my legs, but I can’t go anywhere. I feel my blue blood being drained from me by a cord, and it’s not a good feeling.

Soon enough I am lifted in the air and placed in the dark place again with all the other horseshoe crabs. After what feels like hours, I feel myself lifted into the air again. The warm sun is all around me. Then I am placed down on the wet sand. I’m home! I scurry into the surf and back into the water. What a night and day I’ve had!

Note: Horseshoe crabs blue blood is harvested by the biomedical industry for testing of drugs and medical devices. Their blood is blue because they use copper as a carrier for oxygen, while humans use iron as a carrier of oxygen in their red blood. There are synthetic alternatives to LAL, but their use isn’t fully adopted yet.

It is unknown if all the biomedical industries actually return all the horseshoe crabs they bleed back into the wild as they may be sold for bait instead. There has been a study that horseshoe crabs that are bled and returned to the wild have altered behavior and the females less spawning attempts.

The Atlantic Horseshoe Crab is “Near Threatened” to being endangered.

Check out these websites for more information:
Biomedical bleeding may impact horseshoe crabs spawning behavior and movement

More on horseshoe crab spawning and how to donate to help them!

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Happy World Manta Ray Day!

manta ray named Cherilyn

Manta Ray named Cherilyn (yes, after me!)

Happy World Manta Ray Day! This is Moby, and I’m a manta ray. I’ve been lucky to be featured in this blog, see Moby the Manta Ray: I Am Not a Devilfish Part 1, Moby the Manta Ray Part 2: How I Am Alike and Different From My Cousins the Sharks and Why Manta Rays Are Becoming Endangered and today I felt the need to bring up the state of the ocean I live in.

We manta rays really are gentle giants, reaching lengths of 23 feet (7 meters) and 6,600 pounds (3000 kg). But all we eat are plankton, the tiny plants and animals floating in the ocean. And we don’t have a stinger on our tail like stingrays. Our only defense is our size, but as you’ll find out, it’s no match for humans.

I face so many threats living in the ocean including pollution (especially plastic), ghost nets, and being fished out by fishermen, to name a few.

I’ve heard things are going poorly on land, but at least you’re not swimming around in and eating garbage! I mean that literally—junk food is nothing compared to the microplastic I ingest everyday.

Microplastic are small bits of plastic. Some pieces are grinded down from larger pieces, and some are manufactured that way (like microbeads in beauty products).

I eat plankton, the tiny plants and animals that live in the sea. The microplastic floats around with the plankton. I filter the seawater around me through my gills, and have finger-like gill rakers on my gills that trap the plankton, which I then swallow.

Each gulp of water brings probably thousands (or more!) microplastic bits in which I swallow. This plastic bioaccumulates in my body, which means that little by little the plastic builds up in my body over time.

You, as humans, carry several pounds of plastic in your body. Even human babies are born with plastic in their bodies.

It’s ironic, the very structure that keeps me alive—my gills—helps me to breathe oxygen from the water around me, and also helps me filter out the food I eat— may lead to my downfall.

You see, me and my manta ray friends’ gill rakers are used in a new controversial Traditional Chinese Medicine formula created in modern times. Some TCM formulas date back 2,200 years but not this one. This means now that manta rays are being hunted exclusively for our gill rakers.


We weren’t always well-liked by fishermen in the past because we manta rays would get caught in their nets and ruin them. They nicknamed us “devil rays” because of that and because our curled up head fins look like devil horns.

Phew, don’t get me started on the dangers of fishing nets to manta rays. If we do get caught in a fisherman’s net there’s no guarantee that we’ll get set free in time to survive.


And there’s something called ghost nets which also lead to many manta rays and other large sea creatures dying. Ghost nets are fishing nets that fishermen have abandoned at sea. Many times they are made of a semi-transparent material called monofilament which looks nearly invisible underwater to most sea creatures.

Once tangled in one, it’s likely that the animal, like a sea turtle, shark or dolphin will die without getting enough oxygen. Sea turtles and dolphins need to get oxygen from air and sharks need to swim constantly to move water over their gills to breathe.

How can you help? You can visit the websites below and donate your time or money. Or just learn more about me and my manta ray friends and spread the word about our plight.

Please vote and let legislators know the health of our oceans matter to you (and me especially!).

Manta Trust
Dr Andrea Marshall, the Queen of the Mantas
Manta Pacific Research Foundation
Marine Mega Fauna Foundation
Wild Aid Manta Ray Program

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Ocean Documentary Review: “Diving Deep: the Life and Times of Mike deGruy”

diving deep poster, diving deep documentary, diving deep review

Diving Deep: The Life and Times of Mike deGruy


I just watched “Diving Deep: The Life and Times of Mike deGruy,” a documentary about an ocean filmmaker, scuba diver, deep-sea explorer and entertaining storyteller. I had heard of Mike through the many ocean documentaries I’ve watched over my lifetime, and his infectious enthusiasm for the ocean is unforgettable. He may be recognizable to Shark Week enthusiasts as a host.

The documentary is thourough, starting with Mike growing up exploring the bayous of Mobile, Alabama with his 3 brothers. They were all springboard divers, and Mike’s father’s movies of them diving was one of the many ways Mike was introduced to filmmaking.

He was daring and brave to dive in some of the places he did, like Antarctica and during a white tip reef shark feeding frenzy despite being attacked on the arm by a shark earlier in his life. Mike even dove into the deep sea in deep submersible subs and suits. He was a true explorer who championed for all that is in the ocean, new and old.


Mike was upset that more people didn’t share his enthusiasm for all things ocean, and that corporations would choose profits over exploring. For example BP and the Deepwater Horizon spill in the Gulf of Mexico. It was in his childhood backyard so to speak, and he was very angry about the oil spill from when it happened to years later when we still don’t know the effects of the chemical dispersants used due to lack of scientific funding.


Mike deGruy died in a helicopter crash (February 4, 2012) while going to film James Cameron’s world record setting dive down to the Marianas Trench. An amazing life was cut short but his 30 years of film documentaries lives on.


I saw “Diving Deep: the Life and Time of Mike deGruy” through the International Ocean Film Fest, running through August 9, 2020. It’s available to watch by donation.

Here’s one of his free TED talks, Hooked by an Octopus:

Here’s the documentary’s website Diving Deep”

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10 Questions About Sharks Answered

1. Are sharks vertebrates?

Yes, sharks are vertebrates. Vertebrates have a backbone or spinal column. In the case of sharks, they have a spinal column made out of cartilage, not bone as in other vertebrates like bony fishes.

2.What is a group of sharks called?

A shoal (this applies to other fish as well)

3. What are baby sharks called?

Pups!

4. How many shark species are there?
There are 512 described and 23 un-described shark species (according to Wikipedia)

5. Are sharks endangered?
At least 143 species are on the IUCN red list with 210 more as data deficient (meaning we haven’t studied them closely enough to know how endangered the sharks are). But all sharks are in danger of becoming endangered due to overfishing, pollution, and other threats facing our oceans.

6. How many millions of years old are sharks?
The first sharks appeared 440 million years ago.

7. Which shark is the smallest? Which shark is the largest?
The smallest shark is the dwarf lantern shark, which grows to 7.9 inches (20 cm)
The largest shark is the whale shark, which can grow up to 60 feet (but is found to be 18-33 feet long on average)

8. Are sharks found in freshwater or saltwater?
Most sharks are found in the ocean in saltwater, but the river sharks are found in fresh and brackish water (slightly salty water) in Asia and Australia. The bull shark is unique in that it can live both in fresh and saltwater in tropical rivers worldwide.

9. Do sharks have swim bladders?
No, unlike the bony fishes, sharks don’t have swim bladders but the oil in their livers help them stay afloat.

10. How often do sharks eat?
It varies greatly between shark species. A great white shark can go a month without food after a full meal.

Fun quiz on sharks from NatGeoKids

The diversity of shark sizes graphic

Sharks on endangered species list

List of all sharks on Wikipedia

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Book Review: Escape Galápagos by Ellen Prager

Escape Galapagos book cover

Escape Galapagos by Ellen Prager

Escape Galápagos by Ellen Prager is a middle grade adventure novel. It’ll appeal to most nature and animal lovers, but because the protagonist is fearful of wild animals and being in nature, it also has a wider appeal.

It’s like taking a virtual trip to the Galápagos Islands, which are located west of Ecuador in South America. These are the islands made famous by the naturalist Charles Darwin, who came up with the theory of evolution.

The protagonist, Ezzy, is afraid of wildlife and dislikes being in nature. Her dad (never named) and her younger brother, Luke, are the total opposite. Ezzy and Luke’s mother (an adventurous woman) passed away and their family is on a quest to complete her “wonder list,” a bucket list of places she always wanted to travel to. The Galápagos Islands were first on that list.

Ezzy’s fears of wild animal poop, and of being attacked by wildlife are addressed with humor realistically. A major portion of the book is a hike through one of the smaller islands, Española. It was like I was on the hot and sweaty hike through the island. Animals I had heard of, like blue-footed boobies and Galápagos tortoises, were mentioned as well as those I never thought of being there like locusts (described as huge grasshoppers).

The excitement in the books starts about halfway in when the small cruise ship Ezzy’s family is on gets hijacked. I’ll leave it a surprise why they were hijacked, but it’s for plausible reasons.

It leads up to the climax where Ezzy, Luke and Aiden (a boy Ezzy’s age), are in a race against time to cross one of the islands. Their father is stuck on the boat with the hijackers, and to boot, a volcano on the island has just erupted.

The ending was exciting and a good end to a great middle grade novel. I would recommend this book to any lower middle grader (grades 4-6), especially those that like adventures and/or natural wonders.

Will the Galápagos Islands be on your bucket list after reading this book? They are still on mine!

Ellen Prager has also written another series of books called, “Tristan Hunt and the Sea Guardians.” The first book is called The Shark Whisperer, which is about a boy who can “talk” to sharks. He ends up at a camp for those with special sea abilities (like camouflaging). I will review that book in a future post!

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