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Haystack Rock

Haystack Rock is home to many different kinds of crabs. The most common ones are Red Rock Crab, Oregon Cancer Crab, Dungeness Crab, Lined Shore Crab, Purple Shore Crab, Porcelain Crab, Soft-bellied Crab and the Kelp Crab. These different species all belong to the phylum ARTHROPODA and share the following characteristics: exterior skeleton (exoskeleton), jointed legs, and two pairs of antennae.

Reddish to flesh-colored, the Oregon Cancer Crab (Cancer oregonesis) has a distinctly lumpy, oval carapace (shell). Very reclusive, Oregon Cancer Crabs can be found hiding in muddy crevices of large boulders and in well-protected tidepool hideouts. Oregon Cancer Crabs scavenge for small invertebrates and are themselves eaten by other larger crabs and fish. Carapace width, to 9 inches.

Red Rock Crabs (Cancer productus) with thick, dark red shells and strong, black-tipped pinchers, this crab is an aggressive night-time predator. During the daytime low tides, Red Rock Crabs hide in gravel and rocky areas. Unlike their intertidal cousin, the Oregon Cancer Crab, Red Rock Crabs do not burrow in the sand--they prefer rocky, gravel-filled tidepools. Carapace width to 7 inches.

Dungeness (Cancer magister) are favored by recreational and commercial fishers (and diners) for their flavorful meat and thin shells. Commercial catch in Oregon once reached 16 million pounds (1976-1977 season, ODFW). More common offshore and in estuaries than in the rocky intertidal zone, tidepoolers are more likely to find stray juveniles and molted shells than live, adult Dungeness Crabs. Dungeness are active carnivores, feeding on at least 40 species including clams, shrimp, oysters and worms. Adults reach sexual maturity at 21 months and live as long as 8-10 years. Carapace width to 9 inches.

Small and feisty, the Lined Shore Crab (Pachygrapsus crassipes) can be found high in the intertidal zone in the many nooks and crannies of a mussel bed or barnacle wall. Lined Shore Crabs are small--approximately 1.5 inches across. Their color varies from purple to emerald green with fine stripes across the carapace (shell). Like other shore crabs its primary food is algae and detritus (dead animal and plant tissue) but there have been reports of Lined Shore Crabs catching and eating flies! Predators include gulls, rats, raccoons, anemones and other crabs. It is thought that this shore crab was accidentally introduced from Asia in the late 1800s.

Purple Shore Crabs (Hemigrapsus nudus) are easily identified by their smooth shell, purple-spotted pinchers and hairless legs. Found on rocky coasts and salt marshes from Alaska to Mexico, Purple Shore Crab forage in large groups for detritus, algae and small crustaceans like barnacles. Shore crabs store water in specialized gill chambers which enables them to remain active out of the water for extended periods of time.

Shore Crab Predators include gulls and herons and enthusiastic tidepoolers. Shore Crab pinchers break easily and are slow to grow back. If you capture one of these crabs, handle them very carefully.


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