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Fairfield County has been doing a good job preventing the spread of COVID with 57.7% of residents fully vaccinated. While many are to thank for this level of protection, no one was more vital to the creation of the COVID-19 vaccination than Henry H.S. Waves, the horseshoe crab. Because of horseshoe crabs, like Henry, we are able to ensure that the vaccines we receive are safe and free from contamination.

Our friend Henry was recently brought to stay at the Seaside Center and teach passerbyers about the important role he has been playing in vaccine production. While horseshoe crabs have been around long before the dinosaurs and sharks, it was only discovered in the past century that their unique blood can help detect bacterial contamination. Their ancient immune system has proteins in their blood, known as amebocytes, which form clots and solidify around endotoxins, toxins found in bacteria. Medical researchers were then able to use the amebocyte lysate from the horseshoe crab blood to detect potential bacterial contamination in our vaccines, such as the COVID-19 vaccines.

In addition to being super important to keeping us safe and healthy, Henry is also of noble blood… or at least he is of blue blood. So while Henry might not be royalty, he, like all horseshoe crabs, has blue blood. The oxygen carrying proteins in their blood is called hemocyanin, similar to our hemoglobin. While our hemoglobin contains iron and is red, the hemocyanin of horseshoe crabs contains copper and is blue.

In order to get access to the horseshoe crab blood, researchers take donations. Each year horseshoe crabs are taken from the wild and brought back to labs where scientists take some of their blood. Unfortunately, some of the crabs do not survive the donation. Of the crabs that are returned to the sea, there is evidence suggesting that they do not end up doing as well upon their homecoming. Due to their harvesting and blood donations, populations of horseshoe crabs have been on the decline.

So while Henry is staying with us for a bit, it is important to leave other horseshoe crabs alone and in the wild, since they play such an important role in our medicine as well as the ecosystem of the sound. But if you are eager to interact with horseshoe crabs, we encourage you to come visit Henry here at the Seaside Center. There are so many more interesting things about him to learn, and he would sure like the chance to meet you.

Emma Castiblanco, 2021 Seaside Center Naturalist