NERRS Archives - It's All About The Sea

Are horseshoe crabs actually crabs?

*Horsehoe crab mating season, Lewes, Delaware. Picture credit score: Jacqueline Bedell*

Do you know?

New Jersey and South Carolina at the moment forbid any harvesting of horseshoe crabs, and Delaware restricts harvesting to males solely.

Regardless of their widespread identify, horseshoe crabs are usually not actually crabs (crustaceans), however are extra intently associated to spiders and scorpions. Atlantic horseshoe crabs (Limulus polyphemus), which swarm U.S. coastlines every summer season from Maine to Mexico, have been known as “dwelling fossils” as a result of they predate the dinosaurs by greater than 200 million years. Their easy, laborious shell (exoskeleton) is formed like a horseshoe (thus the identify). They use their lengthy tails as rudders within the water and to flip themselves in the event that they get overturned on the seashore. They’re large reworkers of sediments and feed on a wide range of marine worms and invertebrates, together with some commercially vital fish.

Few folks notice how vital horseshoe crabs are to fashionable medication. As a result of their blue, copper-based blood shortly clots within the presence of bacterial toxins, medical researchers use it to check intravenous medicine, vaccines, and medical units, guaranteeing that they’re freed from bacterial contamination. Yearly, many 1000’s of horseshoe crabs are harvested from their habitats, “bled” of about one-third of their blood, then returned to the seashore comparatively unhurt.

Horseshoe crabs are also vital ecologically. Greater than 20 species of migratory birds, loggerhead sea turtles, and a myriad of business and recreation fish and crab species depend on the crabs’ eggs as an annual boon to their diets.

Whereas Atlantic horseshoe crab numbers had been declining within the Nineties, populations are recovering because of the regional administration efforts of the states by way of the Atlantic States Marine Fisheries Fee. Delaware Bay has the most important inhabitants of horseshoe crabs on the earth, and scientists from NOAA’s Nationwide Estuarine Analysis Reserves System assist conduct annual horseshoe crab spawning surveys, which is a Delaware Bay-wide effort. Nonetheless, habitat loss and excessive demand as industrial bait are nonetheless considerations for horseshoe crabs and migratory shorebirds.

What’s a maritime forest?

Maritime forests are shoreline estuaries that develop alongside coastal barrier islands that assist an amazing variety of vegetation and animals. Many maritime forests in the US stay largely untouched by business improvement and carefully resemble the woodlands the place Native People lived and early colonists settled lots of of years in the past. Timber, bushes, and different vegetation in maritime forests and estuaries face up to sturdy winds, periodic flooding, and salt spray. Many species of mammals and reptiles make the forests their dwelling, and 1000’s of birds migrate to maritime forests annually.

A very good instance of a maritime forest is the Currituck Banks Reserve, situated on the Outer Banks of North Carolina. The western, ocean facet of Currituck consists of sand dunes of seaside grass and sea oats, which entrance a tightly woven cover of shrub-like thickets of wax myrtle, holly, and stunted oaks. The cover acts as a windscreen to guard the forest’s much less tolerant inside bushes, typically consisting of American holly, seaside olive, ironwood, loblolly pine, pink maple, and dwell oak. On the opposite facet of the barrier island’s maritime forest lies the estuary of Currituck Sound, the place contemporary water meets the ocean’s salt water. This shallow intertidal space is dwelling to the estuary’s ample natural world.

Like all barrier islands, maritime forests are always altering and on the transfer. On Currituck, for instance, one can see stumps of deciduous bushes alongside the sandy seaside. These bushes had been as soon as within the heart of the island, however because of the always altering shoreline, they’re now principally submerged within the ocean. Maritime forests, like all estuaries, are important for storm safety. Additionally they preserve essential vitamins and groundwater.

What’s a barrier island?

Barrier islands kind as waves repeatedly deposit sediment parallel to the shoreline. As wind and waves shift based on climate patterns and native geographic options, these islands continuously transfer, erode, and develop. They’ll even disappear solely.

They’re usually separated from the mainland by tidal creeks, bays, and lagoons. Seashores and sand dune techniques kind on the aspect of the island dealing with the ocean; the aspect dealing with the shore typically accommodates marshes, tidal flats, and maritime forests. These areas are essential habitat for seabirds, fish and shellfish, and nesting sea turtles.

Many barrier islands are discovered off the U.S. Gulf and East coasts, such because the Outer Banks off North Carolina. Barrier island chains are inclined to kind close to river deltas and in areas with low tectonic exercise and comparatively flat coastal terrain. The rocky cliffs and shifting tectonic plates off the West Coast, together with different options of the terrain and tides, forestall barrier islands from forming there.

These islands are crucial to defending coastal communities and ecosystems from excessive climate. Seaside dunes and grasses on barrier islands soak up wave power earlier than the wave hits the mainland. This usually means smaller storm surge and fewer flooding on the coast.

Sadly, barrier islands are disappearing at an alarming fee. Erosion might be attributable to human actions similar to ship visitors, arduous levees, and infrastructure tasks, even these far upriver. Damming and dredging tasks can considerably have an effect on the quantity of sand and sediment accessible to fortify barrier islands. The consequences of local weather change, together with speedy sea degree rise and excessive climate occasions, may cause or worsen barrier island erosion.

NOAA helps pure and nature-based infrastructure tasks that restore and shield barrier islands and the advantages they supply to coastal communities and ecosystems. Hundreds of acres of barrier islands and marshland have been restored or enhanced as a part of Gulf Spill Restoration tasks. These tasks tackle injury to pure assets and wildlife from the Deepwater Horizon oil spill, however the restored barrier islands additionally present added coastal resilience and shield essential estuary habitats.