Category Archives: Species

Cucumaria miniata: Orange sea cucumber–The Race Rocks Taxonomy

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The orange Cucumaria miniata sea cucumber is a common resident just off the docks at Race Rocks in 5 to 10 meters of water. In this video they occur in a high concentration relative to other areas. Each orange tuft is the tentacle mass. If disturbed, it quickly withdraws into the sea cucumber body which is always buried under loose rocks.

Note the name Cucumaria miniata should be on the following video instead of C. curata

General Description:The Orange sea cucumber received its Latin name, Cucumaria because it resembles a cucumber. The orange pigment that separates it from other sea cucumbers comes from a chemical called cinnabar or vermilion. Although it seems to be completely soft and fragile, it actually has bone-like plates in the body wall called ossicles. To stay attached to the holes between the rocks, the cucumber uses tube feet that you can see in the image above in 5 rows around the circumference of the body. If you ever want to keep one as a pet, don’t get too attached because they usually only live about 5 years, sometimes 10 if they’re lucky.

Habitat:

Sea cucumbers live in between boulders and sheltered rock formations. Because they are able to stay attached to surfaces, they prefer to live in areas with stronger currents, making it harder for predators to reach them.

Feeding:

The orange sea cucumber is a suspension feeder. This means that it catches food in its tentacles. After the food is caught, it removes the food with its eating arms and scrapes it into its mouth. Sea cucumbers eat plankton and detritus.

Reproduction:

Unfortunately, sea cucumbers aren’t very intimate creatures. In fact, their mating process can’t have any less contact. When the time comes to make a new cucumber and two cucumbers are physically (and emotionally) ready, one will release eggs into the water and the other will release sperm. From that, the two elements meet in suspension and that’s it.

Predators and Defenses:

The cucumbers main predators include fish, and even humans. That’s right kids, there are some people in the world that actually eat these things. To protect itself, the cucumber has many defenses. Their skin is some of the most amazing tissue found on an animal. The compound is made of a material called ‘catch collagen’ which can change from liquid to solid when neurologically triggered. It does this so can squeeze into small spaces and then harden again. Another defense is they “pee” out all the water in their system and shrink into a small, hard rock. The “peeing” usually occurs when the cucumber is removed from its habitat. If that’s not enough for you, they also can bust out a defense called evisceration. What happens here is if the cucumber is stressed and scared enough, it will spew its guts out. That means everything, intestines, gonads, respiratory organs, everything. Now after that, you would think that’s the end but if it can get itself to a safe habitat, it can actually regenerate its organs.

Biotic Associations

These guys are generally really passive, and they don’t really interact with any other organism or with between each other really.
References:http://oz.plymouth.edu/~lts/invertebrates/Primer/text/holothuroidea.html

http://www.afsc.noaa.gov/hodiak/photo/cuke03.html

Domain Eukarya
Kingdom Animalia
Phylum Echinodermata
Class Holothuroidea
Family Cucumariidae
Genus Cucumaria
Species miniata

Common Name: Orange Sea Cucumber

 

Other Members of the Phylum Arthropoda at Race Rocks 
taxonomyiconReturn to the Race Rocks Taxonomy
and Image File
pearsonlogo2_f2The Race Rocks taxonomy is a collaborative venture originally started with the Biology and Environmental Systems students of Lester Pearson College UWC. It now also has contributions added by Faculty, Staff, Volunteers and Observers on the remote control webcams.

 March OctoberFebruary , 2002, Andres Jennings (PC yr 28)

Metridium farcimen: Giant Plumose Anemone–The Race Rocks Taxonomy

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metridium

Metridium cluster by Ryan Murphy

 

rmmetridium1

The Metridum farcimen polyp can reach well over 30cm in length. Ryan Murphy photo

General description: The Giant Plumose Anemone is a fairly large anemone of typically white, cream, tan, orange or brown colourations. Subtidal animals can often reach 25cm in crown diameter and 50cm in height. However larger specimens have been reported around 75cm in height. Shape of the column is much longer than wide. Tentacles lining the mouth of the oral disk are quite fine, very numerous, slender and short. Tentacle colouration is typically transparent when the tentacles are expanded and take the colour of the column when contracted.Habitat: Found in both subtidal and low intertidal zones, including jetties, wharfs, harbours, breakwaters and floats. When found on wharfs, anemone communities of dense distribution are common. Larger specimens are often found solitarily in the subtidal. The Plumose Anemone ranges from Alaska to southern California and along both sides of America.

These images by Ryan Murphy show the biological associations of which they are a part.

 

Feeding: Both the small and large anemones feed primarily on zooplankton, using their stinging tentacles to catch the prey. The feeding appears non-selective. Scraps of fish and squid and small benthic (subtidal) organisms are also taken.

In this video Ben from Australia introduces us to this abundant anemone found in the waters around Race Rocks. Note the fine tentacles– ideal for trapping plankton in the high current areas. Also note that this is not Metridium senile as labelled, but Metridium farcimen 

Predators: The Plumose Anemone has few predators. Nudibranchs feed on small anemone, while in Puget Sound (Washington State) a sea star (Dermasterias imbricata) has been found to feed on larger anemones.

Reproduction: The anemone reproduces both asexually and sexually. Asexual reproduction occurs as the anemone moves about, leaving small sections of its pedal disk (base) behind, in a process described as pedal laceration. Dense colonies can be formed in this manner, with the pedal disks forming small cloned rounded anemones that feed and grow.

Sexual reproduction occurs in a broadcast spawning process whereby the males release sperm with wedged-shaped heads stimulating the females to release their eggs, about 0.1mm in diameter with a pinkish colouration. External fertilization occurs, with the zygote dividing to form a planula larva which swims in planktonic form. Adam Harding caught this process in action in July .

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Metridium spawning, Adam Harding photo.

 Planulae settle and metamorphose into young anemones.

Biotic Associations: Plumose Anemone symbiosis is an area in which little research has been done. Possible commensal behaviour may be similar to other anemones which have certain fish (e.g Clown Fish) which use the anemone.

Interesting behaviour: Anemones are rich in nematocysts (stinging cells) which are used in both defense and attack. The normal tentacles contain these cells used for both defense and feeding. However, in large colonies of Plumose Anemones the species bordering the colony develop a different type of tentacle; “catch” tentacles. These tentacles, which are used to repel non-cloned anemones, take about 9 weeks to develop close to the mouth and may number as great as 19 on an individual organism. If the “catch” tentacles, which contain a different type of nematocysts, touch another anenome from a separate colony a stinging tip breaks of and releases the separate complement of nematocysts. This technique is used to repel intruding anemones. Interestingly, these tentacles can expand to a possible length of 12cm.

metrid2

Domain Eukarya
Kingdom Animalia
Phylum Cnidaria
Class Anthozoa
Order Actinaria
Family Metridiidae
Genus Metridium
Species farcimen
Common Name: Giant Plumose Anemone

Reference: R.Morris, D.Abbott, E.Haderlie, Intertidal Invertebrates of California (690) pp. 62-63. Stanford University Press, Stanford, California. 1983.

 

Return to the Race Rocks Image Gallery and Taxonomy

This file is provided as part of a collaborative effort by the students, faculty, staff and volunters of Lester Pearson College UWC February 2002 Ben Dougall PC28

Psolus chitonoides: creeping pedal sea cucumber

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Predation of a Psolus chitinoides by a sea star is examined and discussed by Laura and Nadege. The stomach of the sea star surrounds the sea cucumber and the soft neck and mouth of Psolus is well inside the cavity of the sea

 

Sea cucumbers have inhabited the world’ s oceans for about 400 million years. Psolus chitonoides is an unusual species of these marine invertebrates. Its diverse characteristics have given it 4 common names: Armoured sea cucumber, Creeping armoured sea cucumber, Slipper sea cucumber and Creeping pedal sea cucumber.

Compare the tentaclesof Psolus with the end of the California Sea Cucumber to the left. Photo by Dr.A.Svoboda

Tentacles of P.chitinoides

A-Description

As all echinoderms, the creeping pedal cucumber has a spiny skin. Also, its appearance is closer to a chiton than to a sea cucumber (here is the origin of its name “chitonoides“).

1-External features:an oval body (7cm long to 5.8 cm wide) domed dorsally with stiff, shingle-like scales, flat, flexible sole ventrally. Its tentacles(8-10) are dendritic, equal in size, or 8 large and 2 small. Also observing the body, it could be compared to an elongate cylinder lying on its side with the mouth at one end and the anus at the other. The rows of tube feet run the length of the body

2-Internal features: the tentacle ampullae, the rete mirable and cuverian organs are absent . On the other hand, we can observe the presence of retractor muscles. Respiratory trees are “y shaped”. Note that its madreporic body is attached to a dorsal mesentery. Its internal calcareous skeleton is composed as following:calcareous ring with anterior processes only. Psolus chitonoides is characterized by typical skin ossicles, where one type of circular perforated plate (some with knobs coalesced into a raised network) occur only in the ventral sole.

Domain Eukarya
Kingdom Animalia
Phylum Echinodermata
Class Holothuroidea
SubclassAspidochirotacea
Order Dendrochirotida
Family Psolidae
Genus Psolus
Species chitonoides
Common Name: Creeping pedal sea cucumber
B-Physiology and Biology

1-Suspension feeder: tentacles trap larger particles (larger than 2mm) by bending inwards to form a cagelike enclosure. The mouth lips extend toward the particle as the nearest tentacle pushes it into the mouth .

2-Reproduction : the reproductive organs of a sea cucumber generally consist of 1 or 2 tufts of elongated tubules in the forepart of the body cavity.Spawning occurs annually, from mid March ot late May, commonly in the early morning. A spawning male will swab its genital papilla with its tentacles, then lift the tentacles to disperse the sperm . Females release long ropes of brick red eggs; fertilized eggs develop into pelagic lecithotrophic vitellaria larvae. Late larvae and early juveniles are negatively phototatic and settle gregariously.

3- Respiratory system: its water vascular system is a hydraulic system made up of tubes and valves that operate rows of extendible tube feet . As other sea cucumbers, Slipper sea cucumbers respire through their tube feet, body wall and respiratory trees.

4-Chemicals: there are toxic chemicals (saponins) on its tentacles, discouraging predators from nipping the tentacles. For example, even the Kelp Greenling (Hexagrammos decagrammus), which feeds on sea cucumbers, avoids this species.

C-Predators, parasites and commensals

1-Sea stars and fish are the main predators of the Psolus chitonoides.

2-Parasitic forms of flatworms and snails can live inside the sea cucumber

3-Commensal organisms are mostly scales that mimic the colour of sea cucumbers, and crawl on their skin.

D-Habitat

From exposed coast to sheltered inlets; although it seems to prefer clean, vertical rock that is free of sediment. Its soft, flat sole enables it to attach firmly to rock.

E-Range

Aleutian Islands to Baja California ; intertidal to 247m ; common in shallow subtidal areas.

References:

Kozloff, E.N. Keys to the Marine Invertebrates of Puget Sound , the San Juan Archipelago, and Adjacent Regions.

Lambert, P. 1997. Sea cucumbers of British Columbia, Southeast Alaska, and Puget Sound. UBC Press,

Other Members of the Phylum Echinodermata at Race Rocks 
taxonomyiconReturn to the Race Rocks Taxonomy
and Image File
pearsonlogo2_f2The Race Rocks taxonomy is a collaborative venture originally started with the Biology and Environmental Systems students of Lester Pearson College UWC. It now also has contributions added by Faculty, Staff, Volunteers and Observers on the remote control webcams.

 March October 2003-  Rahilla (PC)

Solaster dawsoni :Morning Sun star– The Race Rocks Taxonomy

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Description

Solaster dawsoni, named after its finder is an eight to sixteen armed starfish. Ranging from grey, yellow, brown or red with light patches covering the upper surface of its body, this sea star looks very much like a “sun”. It can grow up to a radius of 25cm (10″) with the central disk in between the arms a third of its total radius. It has radial symmetry and an endoskeleton like most other starfish and again, uses the normal water vascular system. It moves around on tube feet and therefore is a very slow moving animal. It breaths through skin gills.

Habitat

Solaster dawsoni resides in the cold, rocky intertidal and subtidal costal waters of the west coast of America, ranging from Alaska right down to California. It lives on a variety of bottom types, and can survive from the low tide line to around 420 metres (1200 feet) deep.

Feeding

Solaster dawsoni, unlike other species, preys on other sea stars. It is the “feared” predator of the orange cucumber and other starfish have been known to flee when touched by it. It will even prey on its own kind including its very close relative Solaster stimpsoni. This sea star also eats sea cucumbers and diamondback nudibranchs. Solaster dawsoni has to either overlap or grasp its prey before it can secure it and because of its slowness this may be the only way it can catch its prey. Because of sea stars’ “blindness”, a large sea star will sometimes flee when touched by a small one. In this way, Solaster dawsoni has been known to kill larger sea stars than itself.

ReproductionThe sun star spawns in the period of March to June when the ovaries contain the full sized oocytes (eggs). It releases large yolky eggs which float to the surface, where they are fertilized and develop into pelagic non-feeding larvae which are also buoyant. At this stage the larvae can not feed but can swim around. From here they then develop into sea stars.Defences and PredatorsAs the most fearsome of all the starfish, Solaster dawsoni is almost completely safe in the water. As mentioned already, one of this sea stars only predators is in fact, its own species.Biotic interactionSolaster dawsoni is a very passive organism. Living on its own, the only interactions it has are with its prey. Also during reproduction, the male and female are much closer together.

Domain Eukarya
Kingdom Animalia
Phylum Echinodermata
Class Asteroidea
Order Spinulosida
Family Solasteridae
Genus Solaster
Species dawsoni
Common Name: Morning sun star

 

Other Members of the Phylum Echinodermata at Race Rocks 
taxonomyiconReturn to the Race Rocks Taxonomy
and Image File
pearsonlogo2_f2The Race Rocks taxonomy is a collaborative venture originally started with the Biology and Environmental Systems students of Lester Pearson College UWC. It now also has contributions added by Faculty, Staff, Volunteers and Observers on the remote control webcams.

 February 2002 Joe Downham(PC year 28)

Pycnopodia helianthoides: Sunflower star–The Race Rocks taxonomy

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Pycnopodia tend to be found thriving in regions rich in seaweed, in low intertidal zones on rocky shores. They have an arm radius that ranges from forty to sixty-five centimeters. Small juveniles have five arms but develop twenty four by the time they are adults. Pycnopodia have an aboral surface and are usually pink, purple or brown in color. Occasionally they will be red or yellow in color. They also have the ability to regenerate lost arms. Pycnopodia are the largest, heaviest and most active of the Pacific coast sea stars. Pycnopodia feed on Stronglyocentrotus purpuratus (the purple sea urchin), bivalves, polychaetes, chitons, snails, hermit crabs, crabs, sea cucumber, and Leptasterias sea stars . The Pycnopodia utilize over fifteen thousand sucker feet when capturing prey. Their prey is swallowed whole and digested internally, and they have the ability to partially evert their stomach. Antagonistic, combative behavior has been observed when two Pycnopodia encounter one another. The key predator of the Pycnopodia is the King Crab. A fourfold increase in speed has been noted when the Pycnopodia is in contact with a predator. If the Pycnopodia does not escape, the predator will latch on to one of its many arms and begin to feed.

The sea star Pycnopodia helianthoides is one of the largest invertebrate predators at Race Rocks. In this close up view, on the dorsal side, the pinkish tufts contain the pedicellariae (small pincers) and the dermal branchiae (for gas exchange) On the ventral view, the central mouth is surrounded by many tube feet.

In October, 2001, federal Fisheries Minister Herb Dahliwal and the Provincial Environment Minister Joan Sawiki visited Race Rocks to officially proclaim the opening of the Race Rocks MPA. In this video, Ryan Murphy shows the ministers a Pycnopodia.

Domain Eukarya
Kingdom Animalia
Phylum Echinodermata
Class Asteroidea
Order Forcipulatida
Family Asteriidae
Genus Pycnopodia
Species helianthoides
common nameSunflower Star

References cited:

Marine Invertebrates of the Pacific Northwest, Eugene N Kozloff, 1996, University of Washington Press
Intertidal Invertebrates of California, Robert H Morris Donald P Abbot and Eugene C Haderlie, 1980, Stanford University Press
Pacific Seashores- A Guide to Intertidal Ecology, Thomas Carefoot, 1977, J.J. Douglas Ltd

 

Other Members of the Phylum Echinodermata at Race Rocks 
taxonomyiconReturn to the Race Rocks Taxonomy
and Image File
pearsonlogo2_f2The Race Rocks taxonomy is a collaborative venture originally started with the Biology and Environmental Systems students of Lester Pearson College UWC. It now also has contributions added by Faculty, Staff, Volunteers and Observers on the remote control webcams.

 December 2001-  Hannah McKinnnon (PC)

Gorgonocephalus eucnemis: Basket star-The Race Rocks taxonomy

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What are basket stars ?

Basket stars are entirely marine invertebrate animals with a pentaradial symmetry. Their bodies are composed of a central disk with multitudes of arms branching dichotomously forming thousands of branchlets. The central disk can be approximately 14cm and the arms 4-5 times the length of the disk. Their colours vary between individuals and often on different parts of the body ranging from beige to almost white.
Domain Eukarya
Kingdom Animalia
Phylum Echinodermata
Class Ophiuroidea
Order 0phiurida
Suborder Euralina
Family Gorgonocephalidae
Genus Gorgonocephalus
Species eucnemis
Common Name:Basket Star

Habitat.

Can be found in rocky intertidals in areas with high high currents only (~10cm/s or more ). Juveniles typically cling to adults and on octocoral colonies ,while adults locate crevices in which to hide during day and then climb to an elevated point to feed at night.

How do they feed ,On What and When.

When feeding, they extend several of their arms into the water, the branchlets spread out like a fan, oriented so that they are more or less perpendicular to the water current. Macroscopic zooplankton including chaetognaths are caught by an array of microscopic hooks on the arms. Branchlets in the vicinity curl and wrap around captured prey forming a localized knot. Mucus extruded from glands further immobilise the prey. At some point knot-laden arms roll in towards the underside of the disk and the captured prey is transferred to the mouth. At the mouth there is a comb like structure the arms pass through to remove all the trapped prey. The prey is then ingested as the arm is redeployed. The gut is very simple and is contained entirely within the central disk hence if the disk is not puffy and inflated the star is starving.

Reproduction and feeding in Basket stars .

This is an example of a juvenile basket star, nestled into the lobes and surrounded by the polyps of the soft pink coral, Gersemia rubiformis.
G.Fletcher photos.

The sexes are separate and they spawn planktonic larvae. They can grow back their limbs if they happen to get chopped off .They also have tube feet and a water vascular system and also pedicellariae for protection. They are also filter feeders and they have a one way digestive system -meaning that the mouth performs the functions of a mouth plus those of an anus .

Who Preys on them?

Though they are cryptic and difficult to spot, they do have predators. Their main predators are fish and other invertebrates like crabs . There actually isn’t much to eat in a basket star but evidence suggests that most contents of some fish guts are basket star arms .

Biological association.They have mutualistic relations with other animals particularly sponges and Gthe soft coral, Gersemia. In such relationships, both the star and the host animal benefit. They either hide underneath the sponge (because it is poisonous and only a few animals other animals can dare touch it), or they live in canals or openings in sponges called ostia . The star thus gains protection from predators and at night it is usually seen sweeping over the surface of the sponge removing the large debris clogging the sponge and consumes it, and once again the star gains something –food. However, the sponge also benefits in that it gets cleaned whereas if it had continued clogged with debris as it was, its feeding efficiency would be reduced since it’s a filter feeder

References

www.reefs.org–(date-1/31/02) ,

Intertidal Invertebrates of California –(Robert H .Morris et.al.)

Other Members of the Phylum Echinodermata at Race Rocks 
taxonomyiconReturn to the Race Rocks Taxonomy
and Image File
pearsonlogo2_f2The Race Rocks taxonomy is a collaborative venture originally started with the Biology and Environmental Systems students of Lester Pearson College UWC. It now also has contributions added by Faculty, Staff, Volunteers and Observers on the remote control webcams.

 February-2002- Moreblessing Nkomo (Zimbabwe) (PC yr 28)

Mytilus californianus: California Mussel

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musshand2

Very old and large Mytilus californianus in the intertidal zone at Race Rocks. This is one of the advantages of long term preservation of the area as an Ecological Reserve.

The pea crab (as one can see in the picture), Fabia subquadrata is found in 1 to 3% of California mussels along the central California coast and 18% of mussels along Vancouver Island. This is a parasite that lives within the shell, because they rob food from their host and sometimes damage one of the gills. Public health codes usually prohibit the marketing or serving of parasitized animals but since the pea crab is very tasty, organisms with this crab are sometimes sold. Moreover, in a small portion of the population you can find imperfect pearls. These are of no value. http://www.lanecc.edu/science/zonation/mussel.htm (accessed 31 January 2002)

Morris, R., P. Abbott and E. Haderlie. 1980. Intertidal Invertebrates of California. Stanford University Press, Stanford, California. 690 pages.
Domain Eukarya
Kingdom Animalia
Phylum Mollusca
Class Bivalvia
Subclass Pteriomorpha
Order Mytiloida
Family Mytilidae
Genus Mytilus
Species californianus

Common Name: California mussel
Other Members of the Phylum Mollusca at Race Rocks.

taxonomyiconReturn to the Race Rocks Taxonomy
and Image File
pearsonlogo2_f2The Race Rocks taxonomy is a collaborative venture originally started with the Biology and Environmental Systems students of Lester Pearson College UWC. It now also has contributions added by Faculty, Staff, Volunteers and Observers on the remote control webcams.
Simon Michaud PC Yr. 28



Pandalus danae: Coonstripe shrimp –The Race Rocks Taxonomy

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Ryan Murphy took the pictures on this page and followed up in getting the identifications sorted out between this shrimp and Pandalus stenoplepsis and verification from Greg Jensen of the University of Washigton.

GENERAL DESCRIPTION

The coonstripe shrimp has large eyes, a thick shell and a surface finely pitted. The color of the shrimp is transparent, milky, and has irregular stripes and spots of chocolate brown all over the body, including its antennae. The antennae are long and heavily banded. Total length of the male shrimps can become about 123mm and the females about 140mm.

HABITAT

As one of the common names suggests, the dock shrimp is often living on or by wooden wharves, in shallow water bays and inlets. The coonstripe shrimp ranges from Alaska to central California.

FEEDING

The diet of the shrimp consists mainly of amphipods, mysids and polychaete worms.

PREDATORS

Lingcods are the main predators, except for humans who exploit the shrimp in the prawn industry.

REPRODUCTION

The shrimp lives about three years. Each of the shrimps starts the life cycle as male and the first fall, breeds come. By the time the shrimp has reached its second spring, the shrimp becomes a female and breeds come fall. After that happens as a female the shrimp holds the fertilized eggs until the hatching come spring.

REFERENCES

Links:
http://www-heb.pac.dfo-mpo.gc.ca/english/programs/fhiip/species/coonstrp.htm

References:
A Bibliography of Shrimps of the Family Pandalidae by J.C. Scrivener
Shrimps of the Pacific Coast of Canada by T.H. Butler
Pacific Coast Crabs and Shrimps by Gregory C. Jensen

Other Members of the Phylum Arthropoda at Race Rocks.

taxonomyiconReturn to the Race Rocks Taxonomy
and Image File
pearsonlogo2_f2The Race Rocks taxonomy is a collaborative venture originally started with the Biology and Environmental Systems students of Lester Pearson College UWC. It now also has contributions added by Faculty, Staff, Volunteers and Observers on the remote control webcams.

This file was originally written by Anna Ihle Thingnaes,  Pearson College student year 28 in January 2002

 

Phyllolithodes papillosus: Heart Crab –The Race Rocks Taxonomy

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The Heart Crab – Phyllolithodes papillosusGeneral Description:

This very distinct crab is most commonly identified by the heart shaped markings on its back, hence his common name, the Heart Crab. This triangular carapace measures from 50X60mm (female) to 90X90mm (male), and is coloured a muddy greenish brown with dark red ridges. The claws, legs and carapace are covered in prickly spines, which helps to camouflage and as a defense mechanism. The Heart Crab has three pairs of walking legs coloured dark brown and a pair of chelipeds that are dark brown with turquoise bumps. Another distinction that is evident on the Heart Crab is the two blunt horns above his eyes and a large spine between them.
Domain Eukarya
Kingdom Animal
Phylum Arthropoda
Class Malacostraca
Order Decapoda
Family Lithodidae
Genus Phyllolithodes
Species papillosus
Common Name: Heart Crab
Habitat and Range:

The Heart Crab is rarely sighted in the open nor do they inhabit the intertidal zone, instead they prefer to live subtidally in a rocky habitat, hiding in crevices with moderate exposure and strong currents. They range along the Pacific coast of North America from Alaska to California inhabiting areas as deep as 183m.

Predators and Prey:

The main predator of the Heart Crab is the octopus, and the main prey of heart crabs are sponges and sea urchins, however they are observed eating other things in captivity.

Reproduction:

All mature female Heart Crabs undergo an obligate molt occuring in the spring, from March through May. At this time of molting female are held by the chelipeds of a male. After the molting is finished and the female’s exoskeleton has hardened, the couple copulate. During this a ribbon containing spermatophores is attached around the female. The fertilization occurs within hours, after this the male separates from the female. The female then incubates her eggs for almost twelve months. Eggs are layed in the late summer, August through September. Newly laid eggs are bright yellow, orange or dark red coloured which eventually dull to a muddy brown prior to hatching.

Biotic Association:

An interesting behavior observed of the Heart Crab is the form of symbiosis,commensalism, the association between two organisms when one organism benefits and the other is neither harmed nor benefited. After molting, the Heart Crab takes shelter under the tentacle canopy of the snakelock anemone, as he is not harmed by this and the crab is protected,
References:Accessed Jan.25, 2001

http://oceanlink.island.net/oinfo/biodiversity/heartcrab.html

http://www3.bc.sypatico.ca/kerryw/creature/heart.htm

http://www.afsc.noaa.gov/kodiak/photo/triangle.htm

 

Other Members of the Phylum Arthropoda at Race Rocks 
taxonomyiconReturn to the Race Rocks Taxonomy
and Image File
pearsonlogo2_f2The Race Rocks taxonomy is a collaborative venture originally started with the Biology and Environmental Systems students of Lester Pearson College UWC. It now also has contributions added by Faculty, Staff, Volunteers and Observers on the remote control webcams.

Cait Caines–year 28(PC)

Acmaea mitra: whitecap limpet– The Race Rocks taxonomy

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Introduction:The White Cap Limpet, very common on the British Columbia coast, is usually found on the lower zones as compared to the intertidal zones of other limpets. White cap limpets shells are white in colour amd rather thick in nature. The animal extends from 19-44cm (0.75-1.75″) in size.

The limpet, however, can only be seen as white after it is dead. When alive, it usually is covered by a pinkish coralline algae, Lithothamniom sp. which is also its main source of food. This forms an excellent comouflage. It’s predators include sea stars.

References: now defunct
http://web.mit.edu/corrina/tpool/limpets.html#whitecap
http://www.gastropods.com/shell_pages/m/Shell_Acmaea_mitra.html
taxonomyiconReturn to the Race Rocks Taxonomy
and Image File
pearsonlogo2_f2The Race Rocks taxonomy is a collaborative venture originally started with the Biology and Environmental Systems students of Lester Pearson College UWC. It now also has contributions added by Faculty, Staff, Volunteers and Observers on the remote control webcams. January2002-Amardeep Kaur (PC yr. 27)