What are Horseshoe Crab Blood Uses?

horseshoe crabs, horseshoe crab blood uses
Horseshoe Crabs mating on the beach (via Wikimedia Commons)

What are Horseshoe Crab Blood Uses and How Do They Spawn?

Spawning time!


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.

Where am I going?

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?

Where am I?


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.

Back home!

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: So what are horseshoe crab blood uses? 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 have 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!

And check out Plankton:The Real Monsters of the Ocean

Manta Ray Day!

manta ray named Cherilyn
Manta Ray named Cherilyn (yes, after me!)

Manta Rays!

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”

10 Cool Shark Facts: Your Questions Answered!

bull shark bahamas, bull shark, bahamas
Bull Shark By Albert Kok~enwiki – Own work, CC BY-SA 4.0

The following are 10 Cool Shark Facts in a question and answer format.

1.How many shark species are there?

There are 512 described and 23 un-described shark species (according to Wikipedia)

2. 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!

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.

And the final cool shark fact is:
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.

Also see: 10 Not-so-Scary Tiger Shark Facts

10 Interesting Great White Shark Facts

and Great White Shark’s Adventure at the Monterey Bay Aquarium

Fun quiz on sharks from NatGeoKids

The diversity of shark sizes graphic

Sharks on endangered species list

List of all sharks on Wikipedia

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!

Review of documentary Sharkwater: Extinction by Rob Stewart

Rob Steward
Rob Stewart, award-winning biologist, photographer, conservationist, author and filmmaker

I just watched Sharkwater: Extinction (2018) a documentary that stars shark and ocean conservationist Rob Stewart. It’s the sequel to Sharkwater, which came out in 2007. According to the Sharkwater.com biography on Rob, his documentaries along with his activism, has saved 1/3 of the world’s sharks.

But sadly, I learned that 150 million sharks are killed a year, double the 73 million sharks a year number I heard many years ago. Sharks are killed not just for the shark fin trade anymore—shark can be found in cosmetics as squalene or squalane, in pet food or livestock feed and in the “fish” sold in stores and restaurants. Much of the fish in sold in stores is mislabeled, or in the case of shark intentionally mislabeled (maybe by the distributor or fisherman) so consumers will buy the product. It’s dangerous to eat shark because they are full of toxins like mercury. It’s recommended that pregnant women and children don’t eat shark because of that.

Rob and his cameraman got great footage of two sharks still alive in a gill net, but about to meet certain death. They were not able to save the sharks, but their footage helped convince legislators in California to ban gill nets in 2018. Gill nets can be miles long and are made of a clear monofilament that practically disappears underwater. Large animals such as sea turtles, sharks, whales and seabirds swim into the net and get stuck. All the above animals, except most sharks that need to keep swimming to get oxygen, need air to breathe. These caught animals drown before the fishermen pull the nets up.

Gill nets are used in target fisheries, such as for swordfish. Anything not a swordfish is considered bycatch. According to Oceana, an ocean conservation non-profit, up to 63 billion pounds of bycatch is caught every year and thrown back into the ocean. When Rob made Sharkwater: Extinction in 2016, it was only estimated to be 54 billion pounds. Sadly bycatch numbers are up. As is the sobering possibility that by 2050, there will be more plastic and trash in the ocean than fish.

It’s a sad documentary to watch in general, because much of the documentary is footage of shark fins or dead sharks. But there is enough footage of Rob swimming with sharks to be inspiring. The end is sad because Rob passed away before the documentary was complete, and his death completed it. He had been using a rebreather, which is advanced diving, while scuba diving off of Florida. He was looking to film a sawfish in the wild. A rebreather is great for filming wildlife because it produces no bubbles. Instead the carbon dioxide you breathe out is scrubbed out and you breathe in clean oxygen.

The ending montage made me cry, and not just because Rob had died. It’s his moving words that are inspiring. Thanks to his documentaries, his legacy will live on in shark conservationists worldwide. Please visit Sharkwater.com and read, 10 Easy Ways to Save Sharks and watch on Amazon Prime for free (if you’re a subscriber).

Meet the Pink Manta Ray!

pink manta ray, manta ray Australia
Pink Manta Ray from Australia photo by Kristian Lane/Instagram

Yes, I’m really a pink manta ray

My belly is pink, whereas in “normal” manta rays their belly is white with black spots and splotches on it. I’ve been nicknamed “Inspector Clouseau” from the movies and tv program called the Pink Panther. You clever humans!

Why am I a pink manta ray?

I don’t know, I think I was just born that way. You intelligent humans have ruled out stress. From a small skin sample (a biopsy) they have ruled out a diet full of red food, it’s not an infection or a genetic mutation.

My pink pigments

So now you humans guess that it’s a “unique expression of melanin” or that my skin pigments are just “off”. Duh, I could’ve told you that! After all there are “strawberry blonde leopards,” and “fuchsia grasshoppers,” due to something called erythrism. That causes animals to appear reddish or pinkish.

I’m a boy!

I was first seen in 2015 off of Australia’s Lady Elliot Island. I’m now 11 feet wide (wingtip to wingtip) and yes, I’m a boy. I was last seen as part of a courting train, which is when a line of males (in this case 8) chase a female to try and mate with. Her pheromones are quite irresistible! If she’s looking for unique, I’ve got all the other boys beat–I’m a pink manta ray after all!

My biggest predator…

Even though as a pink manta ray I stand out in a crowd of manta rays, I’m relatively safe from killer whales and great white sharks due to my size. In fact, my biggest potential predator is you humans!

Devil rays

Yes, all manta rays are at risk at being targeted and hunted by humans. Fishermen nicknamed us devil rays because our curled up head fins look like devil horns. We would often get tangled in their fishing nets and ruin them. They really didn’t like that or us because of that.

What are gill rakers?

Now us manta rays are targeted for our gill rakers. They are thin, comb-like strings on our gills that capture all the yummy plankton from the water I strain through my gills. In other words, my gill rakers are what keep me alive!

Even pink manta rays can’t outsmart humans though…

Unfortunately, a new not-so-traditional and controversial formula of Traditional Chinese Medicine utilizes gill rakers and humans now target us gentle and giant beings. We manta rays have the largest brain-to-body ratio of any fish, but alas, even our intelligence cannot keep us from being hunted, possibly someday to the point of extinction. Coupled with our lack of defense (we have no stingers) we have little hope of surviving unless humans stop targeting and killing us faster than we can reproduce. Its no wonder females have a train of males trying to court them—they only mate every two years and have pups every 2-5 years.

Also see Moby the Manta Ray: Happy Manta Ray Day!

For more on how you can help manta rays, visit these ocean conservation non-profits:

Manta Pacific Research Foundation

Manta Trust

Marine Megafauna Foundation

Wild Aid’s Manta Ray Program

Articles used in this blog post:

Rare pink manta ray spotted near Australia’s Lady Elliot Island

How manta rays gill rakers filter water without clogging

Manta ray reproduction

Duffy the Sea Turtle: Children’s Picture Book Review

Duffy's Lucky Escape children's book
Duffy’s Lucky Escape children’s picture book

“Duffy’s Lucky Escape,” by Ellie Jackson and Liz Oldmeadow, is a children’s picture book about a sea turtle. She lives on a colorful coral reef. Duffy was minding her own business when a storm came and washed her out to sea. There her adventure with trash in the ocean began…unknown to her she eats some plastic (sea turtles often mistake plastic bags for jellies). Fortunately she is rescued, rehabilitated, and eventually released back where she belongs.

“Duffy’s Lucky Escape” is based on real events. It is a charming children’s book that gently teaches kids about garbage in the oceans and the dangers that it poses to wildlife.

The illustrations are beautiful and colorful. They are realistic, but still cartoony as you’d expect from a children’s picture book. There are facts about sea turtles at the end as well as ways children can help ocean wildlife such as Duffy. For instance, everyone can use less plastic by using a reusable water bottle instead of single use water bottles and also not use plastic straws.

I highly recommend this book for any school-aged child—it would make a great addition to any library. It teaches in a gentle way, and it has actionable tips so children feel empowered to help ocean wildlife.

There are other Wild Tribe Heroes books. “Marli’s Tangled Tale” is about a puffin who gets tangled in a balloon from a balloon release. Another is “Nelson’s Dangerous Dive” about a whale who gets trapped in fishing nets. A newly released book is “Buddy’s Rainforest Rescue” about an orangutan and palm oil.

For more information, visit Wild Tribe Heroes

Manta Rays Have Social Lives!

manta ray, reef manta ray, Manta alfredi
Reef manta ray (manta alfredi) photo by: Shiyam ElkCloner, Wikimedia Commons

Hee, hee. Did you know manta rays have a social life? I know about manta rays social lives because I AM a manta ray. My name is Molly. Humans have only studied manta rays in depth (probably) for decades. Before we were admired for being a gentle giant, fishermen called us “devilfish.” Our curled up head fins look like devil horns, hence the name. Never mind most of the time we’re feeding and our cephalic fins are uncurled. We’d often get caught in fishermen’s nets by accident. The fishermen would get angry that not only did they have to untangle us, but they often had to repair their nets.

In any case, humans have come out with a research study showing that female reef manta rays (Manta alfredi) “show preference” to other female manta rays. I’d say we’re friends, or acquaintances at least for the short-term. We also remember our contact with each other.

We form bonds with other female manta rays over weeks and months but not necessarily longer. That’s okay as many times after a feeding frenzy, or a stop at a cleaning station, we go our separate ways. We don’t vocalize like whales, who keep in touch at long distances. When we get excited socially we can brighten the white splotches on our black backs. But we do have the largest brain-to-body ratio of any fish so it’s no wonder we can use some of our brainpower to recognize others.

The boys, well they’re on their own unless they group with other males, females and juveniles. The main times we all come together are for feeding (plankton for all!), at cleaning stations (ahh…), and for mating. A train of males will trail a female for a long time until she gives in and mates with one. It’s fun, up to a certain point. Who doesn’t like all that attention?

So although scientists study manta rays social lives, we are in trouble nowadays because of our gill rakers. The very body parts that keep us alive are now threatening our lives. Gill rakers are a covering on my gills, which not only help me breathe, but also feed. The gill rakers act like strainers. They filter ocean water as I swim. Plankton in the water stick to the gill rakers. Plankton are the tiny plants and animals that live in the ocean and are at the bottom of the food chain. The plankton builds up on my gill rakers and yum, time to swallow!

Unfortunately many humans covet our gill rakers for the Traditional Chinese Medicine market. There is no traditional formula that contains manta ray gill rakers, just a controversial new one.

I only have 1-2 pups every 2-5 years. That’s not very often, and we certainly can’t keep up with the fishermen killing us.

Other threats to manta rays, which are making us become endangered, are injuries from being entangled in discarded fishing nets, pollution (especially microplastics) and habitat destruction.

For more information on how you can help visit:

Marine Megafauna Foundation’s work with manta rays

Manta Trust and threats to manta rays

Wild Aid’s work in China to save manta rays

Paper published on 22 August 2019: Rob Perryman et al, “Social preferences and network structure in a population of reef manta rays” Behavioral Ecology and Sociobiology

Also see Meet the Pink Manta Ray

Interview with Shark Scientist Melissa Cristina Marquez

Melissa Cristina Marquez portrait
Shark Scientist Melissa Cristina Marquez

Melissa Cristina Marquez is a Marine Biologist, Wildlife Educator, TV Presenter, TEDx speaker, Podcast Host & Author from Sydney, Australia.

Tell me more about Fins United Initiative-how you got started, what you do, and how people can get involved-what are some ways people can help save sharks?

The organization was first established in 2013 in sunny Florida, and was dubbed as “Sarasota Fins.” Inspired by the lack of shark education and conservation integrated into school curriculum’s, I began creating the tools and products I believed will help inspire understanding of these beautiful creatures. As the program’s popularity grew, its educational outreach expanded and the need for a more encompassing name became clear: thus, The Fins United Initiative was born.

The Fins United Initiative is a shark, skate, ray and chimaera education and conservation program aiming to unite fin lovers worldwide. Our mission is to provide easy-to-access information on all sharks and their relatives worldwide through partnerships with educational institutions and other programs.

We are looking for representatives worldwide – and you don’t have to have a background in marine biology, just a passion for sharks and their relatives – to volunteer their time and go to classrooms, clubs, events, etc and give a #SharkTalk! Contact us here.

How do other cultures perceive sharks (other than as scary or dangerous)?

It really varies on the relationship a culture has with the ocean. Some cultures see sharks as these scary monsters will others perceive them as shapers of the land that are to be respected. I’m hoping to publish more information about this in the near future.

How has your cultural background affected your career?

It has made me a strong advocate for not just diversity in science and science communication but also inclusion. Many people think those terms are interchangeable but they are not the same thing. While science and science communication has become more diverse in the past decade, they still are not inclusive. Science, in general, is a very expensive industry to get into, leaving many at a disadvantage. My career has been shaped by my mission of giving my platform to others to speak their truth and their science.

Tell me more about your books and/or podcast-what are they about and how can we find them?

Joining forces with Speak Up for The Blue podcast, the ConCiencia Azul podcast is COMPLETELY IN SPANISH and interviews Spanish-speaking marine scientists, conservationists, grad students, photographers, and more from around the world. We discuss their studies and some of the unique challenges they face (such as racism, poverty, government corruption, etc).

There are people out there who are doing incredible work that doesn’t get highlighted, which is unfortunate. In many cases, they overcame obstacles, including racism and sexism, poverty, cultural and family expectations, and lack of mathematics background, in order to work and excel in the fields that they love. We Latinos y Latinas have the talent, and we often just lack the opportunity. This is my way of providing that opportunity to shine a light on them.

As for the books, I can’t talk too much about them other than it features an Afro-Latinx family that dedicate their lives to wildlife conservation and education. The series pulls from my life experiences, especially with what the main character (a young female) goes through. More information will be available in the next few months!