Pelagic Red Crabs at Asilomar State Beach, Pacific Grove
In August,
while wandering along the rocky coast in the Pacific Grove area (a favorite
spot), we came across a small stretch of sandy beach nestled between rocky
shoreline. Unlike similar stretches of
beach a few hundred yards away, this one was dotted with bright pelagic red crabs
(Pleuroncodes planipes).
 |
| Pelagic Red Crab (Pleuroncodes planipes), Asilomar State Beach, Pacific Grove |
Typically, this species occurs
at more southern latitudes, in the area of Baja California. But during warm El Nino weather, currents carry them farther north along the coast of California. Pelagic red crabs have a habit of swarming near the surface of the water, possibly to spawn. These masses of crabs are carried by currents and wash up on sandy beaches, causing mass mortality. (A Google Image search will turn up some
pretty incredible photos of beaches covered with pelagic red crabs.)
 |
| Washed up on the beach, this crab is a soon-to-be meal for an opportunistic gull. |
The word
"pelagic" in the common name refers to the open ocean. (As opposed to benthic, referring to the lowest level of a body of water and the
substrate, or littoral, referring to
shallow water near shore.) Though called "pelagic," these crustaceans split their time between swimming freely in the water column and settling on the bottom to lead a more benthic lifestyle; they are not typically associated with the shore.
 |
| Pelagic crab, in the hand |
Pelagic red crabs are a valuable part of the marine ecosystem, filter-feeding on phyto- and zooplankton in the water column and detritus on the sea floor. In the food web, they play the role of converting microscopic plankton to a valuable source of energy for larger predators, such as tuna, sea turtles, some whales and a number of sea birds.
I'm sure the gulls at Asilomar Beach
were thrilled to find that the sea had provided them with an easy meal that
day!
About Me
Named after the Sierra Nevada Mountains, I am a naturalist and avid birder based in Central California. Above all, I am a follower of Jesus Christ, our amazingly good Creator God whose magnificent creation is an unending source of awe and inspiration for me. I hope to inspire others to appreciate, respect and protect this beautiful earth we share, and invite you to come along with me as I explore the nature of California and beyond!
- Siera Nystrom -
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Bethany and I saw a swarm of these swimming at the Monterey Warf. We couldn't tell if they were shrimp or crabs at first. Thanks for the info :)
ReplyDeleteYou're welcome! Thanks for reading!
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