46:
348:
33:
393:
359:. It burrows backwards into the sand and faces the sea. As each wave retreats, it extends its antennae and catches floating organisms. It then retracts the antennae and scrapes the particles into its mouth. It can do this several times per wave. When it becomes uncovered by water, it coils its antennae and burrows backwards deeper into the sand. The diet is
405:. These birds actively patrol the part of the beach washed by incoming waves, probing the softened sand with their bills. The sand crab retreats under the sand surface as each wave goes out, maximizing its chance of being out of reach of the bird's beak. The bird maximizes its chance of feeding on sand crabs by scurrying at the edge of the surf.
282:
The sand crab is well adapted to life in the sand, which presents an unstable substrate, and its shape is an elongated dome shape designed for fast burrowing. The eyes are on long stalks and the antennules are also elongated so as to project above the surface of the sand. These form a tube which
383:
and develop into juveniles, which mature into adults within a few weeks. The long planktonic stage means that the larvae can become widely dispersed and colonize new areas. The adults reproduce in both their first and second summers and most die in the autumn of their second year.
400:
The sand crab lives under the surface of the sand, moving up and down the beach according to the state of the tide. As each wave advances and retreats, the crab comes to the surface and extends its antennae to feed. This makes it vulnerable to predatory birds such as the
327:. The species is common on the beaches of California, but greater changes in population levels occur further north, probably as a result of variations in the coastal currents which in some years passively disperse the planktonic larval stages northwards. In
795:
Ferdin, M.E; Kvitek, R.G; Bretz, C.K; Powell, C.L; Doucette, G.J; Lefebvre, K.A; Coale, S; Silver, M.W (September 2002). "Emerita analoga (Stimpson)—possible new indicator species for the phycotoxin domoic acid in
California coastal waters".
266:
The
Pacific sand crab is a small crustacean growing up to 35 mm (1.4 in) long and 25 mm (1.0 in) wide. The female is nearly twice as large as the male and can often be identified by the orange egg mass carried under the
338:
On any particular beach, the distribution of sand crabs from one part to another can vary greatly for reasons not fully understood. Females tend to be found far down the beach, whereas males and immature crabs are found at higher levels.
370:
The sand crab mates in spring and summer. The female lays batches of up to 45,000 eggs each month and carries them about beneath her abdomen tucked under her telson. The eggs hatch in about four weeks. The larvae have five planktonic
451:
and commercial bait fisheries extract them from the beach. The sand crabs with soft shells that have just moulted are kept for bait, while the hard-shelled crabs are thrown back into the sea.
696:
Johnson, Martin W.; Lewis, Weldon M. (1942). "Pelagic Larval Stages of the Sand Crabs
Emerita analoga (Stimpson), Blepharipoda occidentalis Randall, and Lepidopa myops Stimpson".
1040:
916:
942:
335:
is largely from larvae originating in
California. There is an established population of sand crabs on the Twin Harbors Peninsula of Washington state.
731:
Tam, Y. K.; Kornfield, I.; Ojeda, F. P. (May 1996). "Divergence and zoogeography of mole crabs, Emerita spp. (Decapoda: Hippidae), in the
Americas".
890:
1050:
929:
432:. These are passed on to predators when the predators eat the crabs, and if enough worms are ingested, they have been known to kill the predator.
1045:
968:
779:
594:
Efford, Ian E. (1970). "Recruitment To
Sedentary Marine Populations as Exemplified By the Sand Crab, Emerita Analoga (Decapoda, Hippidae)".
355:
The sand crab always moves backwards when burrowing or crawling. It can also swim (backwards) and tread water using its back legs. It is a
250:
found living in the sand along the temperate western coasts of North and South
America. It is found on exposed sandy beaches in the
1007:
570:
501:
671:
271:. The adult is sand-coloured and well camouflaged, and has no claws or spines. It has five pairs of legs and three pairs of
934:
291:
are retractable. When water is overhead, they also project above the sand surface to collect food particles. The legs and
864:
947:
631:"Larval dynamics of the sand crab, Emerita analoga, off the central Oregon coast during a strong El Nino period"
45:
529:
832:
869:
295:
have hairy margins to assist in digging and for use in collecting food and transferring it to the mouth.
675:
332:
160:
1012:
740:
489:
137:
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stage. The zoeal stages last up to 130 days. The megalopae settle out onto sandy beaches where they
558:
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436:
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177:
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809:
32:
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The sand crab has been evaluated as an indicator species for monitoring the level of
771:
448:
444:
87:
428:. The crabs are hosts to the intermediate stages of various parasitic worms, like
994:
903:
469:
455:
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417:
276:
210:
107:
855:
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443:), found off the coast of California, consumes a large number of sand crabs.
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284:
830:
331:, the populations seem not to be self-sustaining and
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311:and in South America, where it is found from
8:
567:Natural History of Orange County, California
303:The sand crab occurs in North America from
827:
275:. Sand crabs moult periodically, so their
31:
20:
646:
1041:Crustaceans of the eastern Pacific Ocean
408:Other birds that eat sand crabs include
480:
351:Underside of female sand crab with eggs
768:The Northwest Coast: A Natural History
524:
522:
520:
518:
396:Sand crab burrowing back into the sand
666:
664:
662:
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658:
283:channels water downwards through the
279:may be found washed up on the beach.
7:
589:
587:
552:
550:
468:spp.) which sometimes cause toxic
14:
571:University of California, Irvine
559:"Pacific Sand Crab (Mole Crab),
502:World Register of Marine Species
44:
629:Sorte, C. J. (September 2001).
1051:Taxa named by William Stimpson
1:
1046:Crustaceans described in 1857
810:10.1016/S0041-0101(02)00129-0
472:off the coast of California.
766:Schultz, Stewart T. (1990).
635:Journal of Plankton Research
1067:
243:of small, sand-burrowing
193:
185:
166:
159:
41:Scientific classification
39:
30:
23:
648:10.1093/plankt/23.9.939
608:10.1163/156854070x00248
530:"The Pacific Mole Crab"
363:, mostly consisting of
319:, southwards to around
441:Amphistichus argenteus
397:
352:
676:Monterey Bay Aquarium
395:
350:
16:Species of crustacean
774:. pp. 129–130.
770:. Portland, Oregon:
422:blackbellied plovers
745:1996MarBi.125..489T
698:Biological Bulletin
237:coldwater mole crab
753:10.1007/BF00353262
447:use the crabs for
398:
353:
323:and into southern
287:. The much longer
1023:
1022:
982:Open Tree of Life
833:Taxon identifiers
781:978-0-88192-418-3
557:Peter J. Bryant.
494:(Stimpson, 1857)"
357:suspension feeder
233:Pacific mole crab
229:Pacific sand crab
220:
219:
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208:Philippi, 1860 –
201:
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804:(9): 1259–1265.
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488:DecaNet (2023).
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465:Pseudo-nitzschia
437:barred surfperch
430:acanthocephalans
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841:Emerita analoga
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710:10.2307/1538014
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561:Emerita analoga
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492:Emerita analoga
487:
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365:dinoflagellates
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309:Baja California
301:
264:
256:intertidal zone
224:Emerita analoga
205:Hippa chilensis
181:
174:
170:Emerita analoga
168:
155:
152:E. analoga
43:
25:Emerita analoga
17:
12:
11:
5:
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739:(3): 489–497.
733:Marine Biology
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688:
654:
641:(9): 939–944.
621:
602:(3): 293–308.
583:
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479:
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458:-synthesizing
445:Surf fishermen
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254:region of the
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161:Binomial name
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772:Timber Press
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704:(1): 67–87.
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679:. Retrieved
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574:. Retrieved
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537:. Retrieved
505:. Retrieved
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440:
434:
418:surf scoters
407:
399:
375:and a final
373:zoeal stages
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302:
299:Distribution
281:
277:exoskeletons
265:
236:
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209:
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114:Infraorder:
88:Malacostraca
24:
18:
995:SeaLifeBase
904:iNaturalist
672:"Sand crab"
596:Crustaceana
456:domoic acid
333:recruitment
262:Description
211:nomen nudum
108:Pleocyemata
1030:Categories
476:References
403:sanderling
248:crustacean
104:Suborder:
78:Arthropoda
1036:Hippoidea
535:. LiMPETS
377:megalopal
325:Argentina
321:Cape Horn
313:Salaverry
146:Species:
64:Kingdom:
58:Eukaryota
922:10238975
878:BugGuide
856:Q3014312
850:Wikidata
818:12220710
681:July 21,
616:20101692
576:July 21,
539:July 21,
361:plankton
289:antennae
273:pleopods
187:Synonyms
178:Stimpson
128:Hippidae
124:Family:
98:Decapoda
74:Phylum:
68:Animalia
54:Domain:
896:2225698
798:Toxicon
741:Bibcode
718:1538014
460:diatoms
426:curlews
414:godwits
410:willets
388:Ecology
343:Biology
293:uropods
245:decapod
241:species
239:, is a
189:
180:, 1857)
139:Emerita
134:Genus:
118:Anomura
94:Order:
84:Class:
1013:467695
987:520619
974:467695
961:595774
948:101204
883:603684
870:503268
816:
778:
716:
614:
507:1 June
470:blooms
424:, and
329:Oregon
305:Alaska
269:telson
227:, the
1008:WoRMS
1000:26669
935:98136
917:IRMNG
909:47414
714:JSTOR
612:JSTOR
533:(PDF)
498:WoRMS
381:moult
285:gills
252:swash
969:OBIS
943:NCBI
930:ITIS
891:GBIF
865:BOLD
814:PMID
776:ISBN
683:2011
578:2011
541:2011
509:2023
449:bait
435:The
317:Peru
806:doi
749:doi
737:125
706:doi
643:doi
604:doi
307:to
235:or
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802:40
800:.
747:.
735:.
712:.
702:83
700:.
674:.
657:^
639:23
637:.
633:.
610:.
600:18
598:.
586:^
569:.
565:.
549:^
517:^
500:.
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420:,
416:,
412:,
367:.
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258:.
231:,
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808::
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751::
743::
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708::
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606::
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563:"
543:.
511:.
490:"
462:(
439:(
176:(
Text is available under the Creative Commons Attribution-ShareAlike License. Additional terms may apply.
