Holland Lifelong Learning - Knot the Typical Connection: Horseshoe Crabs & Shorebirds | South Carolina Aquarium

Holland Lifelong Learning – Knot the Typical Connection: Horseshoe Crabs & Shorebirds

Nov 22

Holland Lifelong Learning – Knot the Typical Connection: Horseshoe Crabs & Shorebirds

When asked, “How many of you have been in a long distance relationship before?”, nearly everyone raised their hand at the third session of Holland Lifelong Learning, held at the South Carolina Department of Natural Resources (SCDNR) outdoor classroom on Wednesday, November 16th. The farthest long distance relationship in the room was between Fiji and Boston, MA, an astounding 8,000 miles apart. This incredible distance somewhat compares to the distance traveled by a very small shorebird, the red knot (Calidris canutus rufa). This bird travels roughly 9,000 miles each year in search of something “they can’t live without” – horseshoe crab eggs. It was long believed that the Delaware Bay was the most important area for horseshoe crab nesting. Dr. Al Segars, SCDNR veterinarian and featured speaker, taught us just how important South Carolina nesting grounds are.

The red knot doubles its body weight during a three-week feast on horseshoe crab eggs, preparing them for the long trip back to their Arctic breeding grounds. The red knots’ dependence on horseshoe crab eggs mirrors human dependence on horseshoe crab blood.

Historically, Native Americans used horseshoe crabs as “Tupperware” and tools. For many years, horseshoe crabs were also used as fertilizer. In the 1970s, the importance of their blood was realized. As Dr. Segars explained, horseshoe crabs contain amoebocytes instead of white blood cells in their copper-based blood. This unique chemical composition surrounds and clots to protect them in a bacteria-laden, ocean floor environment. Now, their blood is used in testing to clot around gram negative endotoxins before a solution is approved for human use.

However, this all comes at a price. The Delaware Bay is experiencing an 80% decline in their horseshoe crab population due to improper harvesting for eel and whelk bait, among other reasons. Locally, the effects of Hurricane Matthew, sea level rise, and the increased presence of humans and their canine companions on our beaches are making it more difficult not only for horseshoe crabs to spawn, but red knots to feast on their eggs. If the red knots cannot get to the eggs (whether they’re underwater or out of fear of our four-legged friends running towards them), how can they prepare their bodies for migration?

South Carolina is proactively setting high standards for permitting, protecting, and conserving these animals. Current technology has empowered and enabled the public to report mistreatment of horseshoe crabs, such as improper handling. Institutions such as Charleston’s Charles River Laboratories are committed to maintaining animal health throughout their process of collecting, bleeding and releasing of horseshoe crabs. Other advancements, such as the creation of holding ponds, have allowed for accurate harvesting amounts, further decreasing the already low mortality rate.

The theme of the night was certainly “relationships”- those between shorebirds and horseshoe crabs, those between humans and animals, but Dr. Segars alluded to a relationship that’s the most important of all – the relationship we have with our children.

Dr. Segars recalled a horseshoe crab tagging experience in which a twelve year old girl was “dragged to the beach” by her mother. She told her mom that she would not touch one of “those things.” After spending time with the hesitant volunteer, she was introduced to the importance and anatomy of the horseshoe crab, not only did she “touch one of those things,” but she set out on a mission to collect the highest number of horseshoe crabs in the survey group for tagging. In a changing world, we all have to do our part to be better stewards for the environment, and inspire our future generations to get outside, appreciate natural wonders, and become the stewards of tomorrow. For more information about getting involved with horseshoe crab tagging experiences, go to http://www.dnr.sc.gov/volunteering/.

Holland Lifelong Learning is made possible by the generous support of Mary and Mason Holland and their commitment to the Watershed Campaign.


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