Cancer irroratus

This crab species occurs on the eastern coast of North America, Labrador Canada to Iceland to South Carolina. Rock crabs live over a large depth range, from well above the low tide line to as deep as {{convert|2600|ft}}. And live up to 8 years. Cancer irroratus has nine marginal teeth on the front edge of the carapace beside each eye,{{cite web |author=Krista Page |year=2002 |title=Cancer irroratus, Atlantic rock crab |url=http://animaldiversity.ummz.umich.edu/site/accounts/information/Cancer_irroratus.html |access-date=June 12, 2011 |work=Animal Diversity Web |publisher=University of Michigan}} and reaches a carapace width of {{convert|5.25|in}}. These crabs are similar in color to, and overlap in size with, the Jonah crab, Cancer borealis.{{cite book |author=Alice Jane Lippson & Robert L. Lippson |year=2006 |title=Life in the Chesapeake Bay |edition=3rd |publisher=Johns Hopkins University Press |isbn=978-0-8018-8338-5 |chapter=Deeper, open waters |pages=[https://archive.org/details/lifeinchesapeake00lipp_0/page/258 258]–289 |url=https://archive.org/details/lifeinchesapeake00lipp_0|url-access=registration }} The two species can indeed be distinguished by the purplish-brown spots on the carapace of C. irroratus (contrasting with the yellow spots of C. borealis), and by the smooth edges to the teeth on the edge of the carapace (denticulate in C. borealis). Males can range up to 8–127mm, while females can range up to 113mm. The Rock Crabs, they usually molt in between the months of April and July.{{Cite journal |last=Haefner |first=Paul A. |date=August 1976 |title=Distribution, reproduction and moulting of the rock crab, Cancer irroratus Say , 1917, in the mid-Atlantic Bight |url=https://www.tandfonline.com/doi/abs/10.1080/00222937600770291 |journal=Journal of Natural History |language=en |volume=10 |issue=4 |pages=377–397 |doi=10.1080/00222937600770291 |bibcode=1976JNatH..10..377H |issn=0022-2933|url-access=subscription }} The two fount claws of the crab are very important because they are the ones that can grab pray as well as holding it while eating it.

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During the month of June if the male gonads are larger than 101 mm then that means they are well developed and mature. If it is less that 50 mm then that means that they are undeveloped or in an early stage of maturity. Females smaller than 70mm are in early stage of ovarian development.{{Cite journal |last=Haefner |first=Paul A. |date=August 1976 |title=Distribution, reproduction and moulting of the rock crab, Cancer irroratus Say , 1917, in the mid-Atlantic Bight |url=http://www.tandfonline.com/doi/abs/10.1080/00222937600770291 |journal=Journal of Natural History |language=en |volume=10 |issue=4 |pages=377–397 |doi=10.1080/00222937600770291 |bibcode=1976JNatH..10..377H |issn=0022-2933|url-access=subscription }} During the reproduction season they tend to go to shallow waters like tilted pools or rocky areas. After females and male mate, the females will lay between 125,000 and 500,000 eggs. After the eggs are laid between the month of June and September, the larval crabs stay in the water until they hatch then after two mouths being in the larval stage they start the baby crab stage where they can finally hunt for food.{{Cite web |title=Cancer irroratus: Atlantic rock crab |website=Animal Diversity |access-date=February 25, 2025 |url=https://animaldiversity.org/accounts/Cancer_irroratus/}}

Atlantic Rock crab diet mostly consist of shellfish like worms, clams, mussels, sea urchins, and even other crabs. But where they get most of the energy from is eating mussels because mussels provide the crabs with all the fatty acids that they need.{{Cite journal |last1=Drolet |first1=David |last2=Riley |first2=Cyrena |last3=Robert |first3=Sonia |last4=Estrada |first4=Rafael |last5=Gianasi |first5=Bruno L. |last6=McKindsey |first6=Christopher W. |date=2022-07-22 |title=Effect of Aquaculture-Related Diets on the Long-Term Performance and Condition of the Rock Crab, Cancer irroratus |journal=Frontiers in Marine Science |language=English |volume=9 |doi=10.3389/fmars.2022.865390 |doi-access=free |bibcode=2022FrMaS...965390D |issn=2296-7745}} Atlantic rock crabs are most vulnerable when they are caught in lobster traps and as well lobster eating the tiny rock crabs when they are still in a larva stage because their shell is soft it doesn't get hard until they are an adult.{{Cite web |title= Cancer irroratus (Atlantic rock crab)|website=Animal Diversity Web |url=https://animaldiversity.org/accounts/Cancer_irroratus/}} Over the years the as the seafood industry became to the more demanding so the Fishermans started to catch Rock crab to sell them in the fish market or have them process by other people,{{Cite web |date=2021-07-14 |title=Rock Crab - What to know, when & where to get it |url=https://montereybayfisheriestrust.org/stories/rock-crab |access-date=2025-04-11 |website=Monterey Bay Fisheries Trust |language=en-US}} but to keep the population steady and not overfishing the crabs there are some regulations for an example fisherman's must have the license, have to have a specific measurement in order to keep the crab (102mm) and forbid people to catch female crab so they can create new offsprings .

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The rock crab has recently become a popular culinary item. The name "peekytoe crab" refers to the fact that the legs are "picked" (a Maine colloquialism meaning "curved inward").{{cite web |url=http://homecooking.about.com/od/seafood/a/peekytoe.htm |title=Peekytoe Crab Information |author=Peggy Trowbridge Filippone |publisher=About.com |access-date=July 13, 2009 |archive-date=September 11, 2016 |archive-url=https://web.archive.org/web/20160911182224/http://homecooking.about.com/od/seafood/a/peekytoe.htm }} Until about 1997, they were considered a nuisance species by the lobster industry because they would eat the bait off of lobster traps. But over time Scientist found out are part of a major ecosystem because they play a role in the food web since they have a much larger diet because they are energy recycling meaning that the process of using energy that would normally be wasted.{{Cite journal |last1=Hanson |first1=John Mark |last2=Comeau |first2=Michel |last3=Rondeau |first3=Amélie |date=2014-08-27 |title=Atlantic Rock Crab, unlike American Lobster, Is Important to Ecosystem Functioning in Northumberland Strait |journal=Transactions of the American Fisheries Society |volume=143 |issue=5 |pages=1266–1279 |doi=10.1080/00028487.2014.931300 |bibcode=2014TrAFS.143.1266H |issn=0002-8487}} As well as heaving crabs as an important development to lobster because lobster eat the soft tissues and a little bit of the hard part of the crab because not only it helps with their growth but also post larva development.{{Cite journal |last1=Gendron |first1=Louise |last2=Fradette |first2=Pierre |last3=Godbout |first3=Guillaume |date=2001-07-30 |title=The importance of rock crab (Cancer irroratus) for growth, condition and ovary development of adult American lobster (Homarus americanus) |url=https://linkinghub.elsevier.com/retrieve/pii/S0022098101002970 |journal=Journal of Experimental Marine Biology and Ecology |volume=262 |issue=2 |pages=221–241 |doi=10.1016/S0022-0981(01)00297-0 |pmid=11445089 |bibcode=2001JEMBE.262..221G |issn=0022-0981|url-access=subscription }} So far, the scientist doesn't know if the population of the rock crab is increasing or decreasing but we do know that with the efforts that we are doing my keeping the populations and reproduction stable we can determine that the Atlantic rock crab won't go extinct anytime soon.

File:Cancer irroratus (Atlantic rock crab) on rocky shore (Bar Harbor, Maine, USA) 1.jpg

Even though the Atlantic Rock crab is important to the ecosystem because it helps steady the population of shrimp and other crabs it's also a threat to some parts of the world. For example, in Iceland and Eastern north Atlantic they recently discovered Atlantic rock crabs that is not native to their island, scientist think they got to Iceland by a larva in ballast water in developed and reproduced in the Icelandic water.{{Cite journal |last1=Gíslason |first1=Óskar Sindri |last2=Halldórsson |first2=Halldór P. |last3=Pálsson |first3=Marinó F. |last4=Pálsson |first4=Snæbjörn |last5=Davíðsdóttir |first5=Brynhildur |last6=Svavarsson |first6=Jörundur |date=September 2014 |title=Invasion of the Atlantic rock crab (Cancer irroratus) at high latitudes |url=http://link.springer.com/10.1007/s10530-013-0632-7 |journal=Biological Invasions |language=en |volume=16 |issue=9 |pages=1865–1877 |doi=10.1007/s10530-013-0632-7 |bibcode=2014BiInv..16.1865G |issn=1387-3547|url-access=subscription }} With the invasion of Atlantic rock crab as well of the successful breeding that is happening in Iceland now the crabs have not colonized Iceland. As well as being the most abundant brachyuran in the areas studied in southwest Iceland.{{Cite journal |last1=Gíslason |first1=Óskar Sindri |last2=Halldórsson |first2=Halldór P. |last3=Pálsson |first3=Marinó F. |last4=Pálsson |first4=Snæbjörn |last5=Davíðsdóttir |first5=Brynhildur |last6=Svavarsson |first6=Jörundur |date=September 2014 |title=Invasion of the Atlantic rock crab (Cancer irroratus) at high latitudes |url=http://link.springer.com/10.1007/s10530-013-0632-7 |journal=Biological Invasions |language=en |volume=16 |issue=9 |pages=1865–1877 |doi=10.1007/s10530-013-0632-7 |bibcode=2014BiInv..16.1865G |issn=1387-3547|url-access=subscription }}

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{{Portal|Crustaceans}}

• {{Commons category-inline|Cancer irroratus|Cancer irroratus}}
• [https://web.archive.org/web/20060716065319/http://www.dfo-mpo.gc.ca/csas/Csas/status/2000/C3-67e.pdf Canada Fisheries and Oceans Stock Status Report 2000]
• {{SealifePhotos|158057}}

{{Edible crustaceans}}

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Category:Cancroidea

Category:Crabs of the Atlantic Ocean

Category:Edible crustaceans

Category:Crustaceans described in 1817