How plastic pollution affects horseshoe crabs, their coastal habitats, and the ocean at large

It is estimated that approximately 8.8 million tons of plastics enter the oceans each year, and this number is expected to double by 2025! Plastic pollution has been found in almost every marine habitat around the world, from sandy coastal beaches to the deepest trenches of the ocean. Plastic bags, straws and cups can be carried hundreds of miles through watersheds and deposited into marine ecosystems.

Mystic Aquarium teens find an adult male horseshoe crab while scouring the beach for trash.

9 out of every 10 items found during our beach cleanups are a single use plastic!

Visible plastics only represent a small fraction of the plastic in the ocean. As a piece of plastic is degraded by the sun and waves, it breaks down into smaller and smaller pieces. Once it reaches sizes smaller than 5 millimeters (smaller than a grain of rice) it is referred to as microplastic. Microplastics, which can include degrading plastic bottles, the plastic exfoliating beads from beauty products, or the fibers shed when washing clothes, add an additional layer of complexity in understanding the potential impact of plastic pollution throughout marine environments.

Often the first images of plastic pollution that come into mind are of a stranded sea turtle with a straw lodged in its nose or a sea lion ensnared in fishing line. But just as larger, charismatic animals are impacted by improperly disposed plastics, so are all marine animals throughout the entire food web. Atlantic horseshoe crabs (Limulus polyphemus) along the New England coast travel each breeding season from deeper waters to the shallows. Throughout these habitats the crabs can become entangled in derelict fishing line, rogue plastic bags, and balloon strings (all of which have been seen during our annual population surveys).

It doesn’t stop there. Horseshoe crabs’ diet includes filter feeding clams, and studies have shown that filter feeders, like clams, mussels and oysters, will ingest minute plastic pieces which can be passed up the food chain to the horseshoe crab.

Mystic Aquarium Ocean Ambassadors scour the beach looking for trash.

As technology advances we are learning more about the volume and kinds of plastics in the environment as well as their impacts, but action needs to be taken now! Working in collaboration with Charles River Laboratories, Mystic Aquarium engages the community in horseshoe crab conservation that is designed to not only educate the public on the plight of the horseshoe crab but also motivate people to make changes to help protect their critical habitats. This may include pairing a beach cleanup with a horseshoe crab survey, conducting water quality surveys of horseshoe crab habitat, or inviting people to kick the single use plastic habit.

This summer the Aquarium’s Sustainability Committee, Youth Conservation Corps, and other volunteers asked restaurants and marinas to skip plastic utensils and use bulk bins, and asked local businesses to serve straws only on request. Additionally, these volunteers plan to remove at least 1500 pounds of marine debris from local beaches before 2020!

Reducing plastic pollution is a global effort in which we all play an important role. Whether you join Mystic Aquarium for one of our upcoming Ocean Ambassador events or start at home in your community, there are individual and collective actions that can be taken now to reduce the anticipated growth in plastic pollution.

  • Advocate for Plastic Free Seas – Talk with your federal, state, and local decision-makers about the importance of reducing the sources of plastic pollution.
  • Choose Sustainable and Reusable Options – Switching to reusable items instead of single use plastic is a great way to keep plastic out of the environment.
  • Catch microfibers at the source – Collect microfibers before they wash down the drain and into waterways by using a filter or microfiber catching laundry ball.

Also, check out an earlier Eureka post from the South Carolina Aquarium on the impact of plastic pollution on sea turtles .