| Northern kelp crab | |
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Scientific classification  | |
| Kingdom: | Animalia |
| Phylum: | Arthropoda |
| Subphylum: | Crustacea |
| Class: | Malacostraca |
| Order: | Decapoda |
| Suborder: | Pleocyemata |
| Infraorder: | Brachyura |
| Family: | Epialtidae |
| Genus: | Pugettia |
| Species: | P. producta |
| Binomial name | |
| Pugettia producta (J. W. Randall, 1840) | |
| Synonyms | |
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Pugettia producta, known as the northern kelp crab or shield-backed kelp crab, is a species of crab in the family Epialtidae. [1]
Its upper carapace is typically dark brown, olive, or olive-brown. The underside surface tends to be more vibrant having colors such as red, yellow, or orange. [2] Younger crabs may be lighter olive-brown or reddish-brown. [3] The carapace is a badge-like shape similar to a police officer's badge or shield; hence the secondary name shield-backed crab. Its carapace is curved and smooth, with a slick texture. The front of the crab has a protrusion called a rostrum, extending the carapace and is used in feeding. [2] They have large chelipeds used for defense and feeding. The northern kelp crab is part of the spider crab family and exhibits the long many jointed hairless legs associated with the family. Their long legs and shield-like carapace are key identifying factors.
It is found along the Pacific Coast of North America from southern Alaska to northern Mexico. [4]
Male crabs tend to be slightly larger than female crabs at about 93 mm (3.7 in) across the carapace. Females tend to be 7.8 cm (3.1 in). Female crabs exhibit a broader back and smaller chelipeds than males. [4]
Northern kelp crabs are known for their association with kelp and their similar coloration. Their long many-jointed legs have evolved to help them climb bull kelp and also provide help climbing man-made pilings. These crabs are also common in lower intertidal zones in beds of algae or eelgrass. They may also be found under rocks or shelters at extreme low tides within the intertidal zones. [5]
Northern kelp crabs are herbivores with seasonal preferences. In the summer months when algae is prevalent, they eat nearly exclusively algae. They eat kelp, rockweed, sargassum, and some types of red algae. Whereas in the winter, they are more carnivorous, eating small mussels, barnacles, bryozoans, and hydroids. This seasonal adaptation is an evolutionary advantage when preferred food is scarce. [3] [2]
The northern kelp crab can be differentiated from similar species like the decorator crabs by its two rows of hooked setae right behind its rostrum. The northern kelp crab sometimes attaches bits of kelp and seaweed to these hooked setae to store as food for later. The northern kelp crab does not decorate its carapace as other majid crabs do. [5]
Northern kelp crabs are predated by a few different animals in different stages of life. Adults are frequently eaten by cabezon, gulls, sea otters, and staghorn sculpins. Sea otters are significant predators of the northern kelp crab within kelp forests. As pelagic larvae (zoeae) they are eaten by Velella velella or the by-the-wind sailor. [4]
The northern kelp crab can be parasitized by Heterosaccus californicus (rhizocephalan sacculinid barnacle) which exhibits a brown mass extending from the crab's underbelly. Once the crab has been parasitized, it will only molt one more time. During this molt, the barnacle then pushes its reproductive sac through the crab's molt-softened carapace. This damages or destroys the crab's male reproductive organs and which leads males to exhibit some female characteristics. These parasite-damaged males may become hermaphroditic and produce both eggs and sperm. Parasite-damaged females may have a faster development of mature characteristics. [4]
Adult crabs migrate to waters as deep as 75 m to mate. They join together, feed, then mate. Females may carry eggs during most parts of the year [3] but are rarely seen in south Puget Sound in May, September, and October. These clutches may be from 34,000 to 84,000 eggs. Eggs change color as they age. They begin bright orange, change to red as they mature, and hatch when they are a grayish purple color. This maturating and development may take anywhere from a month to nearly a year. [4] [3]
This crab has a terminal molt which may end up covered with barnacles, limpets, or bits of algae. [4]
Northern kelp crabs are not attractive for human consumption. They are difficult to purposely catch and bear very little meat. Their chelipeds are large and adept. They have an aggressively strong pinch. [6]
Callinectes sapidus, the blue crab, Atlantic blue crab, or regionally as the Chesapeake blue crab, is a species of crab native to the waters of the western Atlantic Ocean and the Gulf of Mexico, and introduced internationally.
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Petrolisthes elongatus, known as the New Zealand half crab, elongated porcelain crab, blue half crab, blue false crab or simply as the half crab or false crab, is a species of porcelain crab native to New Zealand.
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Cancer productus, one of several species known as red rock crabs, is a crab of the genus Cancer found on the western coast of North America. This species is commonly nicknamed the Pearl of the Pacific Northwest.
Glebocarcinus oregonensis, commonly known as the pygmy rock crab, is a species of crab found on the Pacific coast of North America.
The purple shore crab is a common crab of the family Varunidae that is indigenous to the west coast of United States, Canada, and Mexico. H. nudus was first described in 1847 by Adam White, and in 1851, James Dwight Dana formally classified the species. H. nudus is a small, amphibious crab that is similar physically and behaviorally to Pachygrapsus crassipes and Hemigrapsus oregonensis. The purple shore crab is generally a dark purple color with olive green, red, and white spots. Mating season for H. nudus begins in mid-winter and larval crabs undergo 5 zoeal stages and a juvenile stage. Adult crabs mainly feed on algea but will occasionally scavenge other animals. H. nudus prefers inter-tidal and sub-tidal zones, and it can oftentimes be found sheltering under rocks or other debris. H. nudus demonstrates complex compensatory mechanisms to counteract fluctuating salinity and water oxygen concentrations, permitting it to live in a variety of different environments.
Hemigrapsus oregonensis is a small shore crab of the family Varunidae; formerly classified under the family Grapsidae. It is known under several common names, including yellow shore crab, hairy shore crab, green shore crab, mud-flat crab, bay shore crab and Oregon shore crab. Despite its common name, the crab actually has a wide variety of coloration. It is found along the West Coast of the United States and Canada, specifically along shorelines and similar geographical areas. In 2009, H. oregonensis was included on a list of animals petitioning for the endangered species label, but there was not enough scientific information available for it to be considered as such, so it remains unevaluated to the present day.
Minuca pugnax, commonly known as the Atlantic marsh fiddler crab, is a species of fiddler crab that lives on north-western shores of the Atlantic Ocean.
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Petrolisthes eriomerus is a species of marine porcelain crab found in the eastern Pacific Ocean. It is commonly known as the flattop crab. It is a flattened, rounded animal, with a carapace up to 20 mm (0.8 in) across. It is a filter feeder, and also sweeps food from rocks.
Oregonia gracilis, commonly known as the graceful decorator crab, is a species of crab belonging to the family Oregoniidae. Like other decorator crabs it habitually attaches other organisms to its back. The sessile organisms are attached to hooked setae that act as a sort of velcro attachment. This decoration provides visual and chemical camouflage thus reducing predation risk. Pacific halibut are a major predator of O. gracilis. Other predators include octopus and sea otters. The main food source of O. gracilis is floating kelp and algae that they capture utilizing a waiting strategy in order to maintain cryptosis.
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Macropodia rostrata, common names, the common spider crab, long-legged spider crab, long-legged crab, is a species of marine crab in the family Inachidae. The Macropodia Rostrata visually mimics many other types of small crabs with the exception of its long legs. By attaching algae to their thin legs, they can be confused with the stem of seaweed. This is both a defense mechanism and a predatory advantage, as unsuspecting fish will hide in seaweed beds from nearby predators. This behavior can be absent among larger crabs, and those that live at great depths like giant Japanese spider crabs.
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Calcinus morgani, commonly known as Morgan's hermit crab, is a species of hermit crab in the family Diogenidae found in the Indo-West Pacific region, the type locality being Indonesia.
Libinia spinosa is a majoid crab found in mud and sand bottoms of the Southwestern Atlantic and Pacific oceans. It is a generalist feeder on organisms such as algae, sponges, cnidarians, mollusks, polychaetes, crustaceans, and small fish. It commonly engages in a symbiotic relationship with the medusa Lychnorhiza lucerna.
| Authority control: National |
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