Category Archives: Invertebrate

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)

Moon jellyfish

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Good Morning
WEATHER: Sky Overcast  Vis. 15 Miles Light Rain  Wind West 7 Knots  Sea Rippled
MARINE LIFE: The Eagles arrived early a.m. as usual 14 mature and 5 immature but as the weather deteriorated about 11:30 with the front moving in from the west with 30+ knt winds, all but 3 matures left the area. A small group of surfbirds spent most of the afternoon along the shore by the boat dock somewhat protected from the wind. The 3 Canada Geese spent another day grazing in the grass in the northeast quadrant of Gr. Race then as the winds increased tucked in behind the rocks in the east bay area. We counted 7 Moon Jellyfish( Aurelia aurita) floating amid the logs and debris in the tide wash east side of the boat dock.Most of them were 15-16 cm wide. In the sea they looked bluish -white and translucent.Unfortunately they were somewhat battered as they washed towards shore and Garry said that they were on their last legs so to speak.
HUMAN INTERACTION: 2nd Nature in just after 9 a.m. with Angus,Garry and Chris for a informational staff meeting. Nice to have a visit especially this time of year even if short.
posted by Carol or Mike S at 7:29 AM
Tuesday, February 05, 2002
Good Evening
TEMPERATURE: Max. 8.1C Min. 5.9C  Reset 6.7C  Rain 0.9 mm
posted by Carol or Mike S at 6:07 PM

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

 

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)

Euphausia Pacifica: Krill–The Race Rocks Taxonomy

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A swarm of krill in a kelp bed. November 2006 PC Divers

Euphausia pacifica is, with Thysanoessa spinifera, the most common krill off the West coast of Vancouver Island.General description Krill are shrimp-like in appearance (Body plan of krill).The abdomen is large, and well-developed. Antennules are long, biramous and may be modified in males. Antennae are equipped with large scales. The mandibles usually have a palp and the two pairs of maxillae are small and flattened. All the thoracic legs are similar, and carry a gill formed from a typically branched epipodite and natatory setea. The last one or two pairs of legs however are often reduced or vestigial The first two pairs of pleopodes are modified as copulatory parts in males. along the British Columbia coast range up to 25 mm (1″) in length, but average 16 mm (5/8″) in length.

Habitat Krill undergo a daily or ‘diurnal’ migration, where they spend the daylight hours in the twilight depths of the ocean (~100 m or 300 feet), out of sight of their predators. As the daylight decreases, the krill rise to the surface to feed in the dark on phytoplankton. In the morning, as the sky gets brighter, the krill will return to the twilight zone. A clear day may push the krill as deep as 150 m (450 feet); on a cloudy day, the krill may be at depths of only 60 m (180 feet). Krill are not distributed evenly within a body of water; they form characteristic ‘clouds’ or patches of high biomass in some areas, whereas other areas may be devoid of krill. Euphausia pacifica is found by the Pacific ocean’s coast from the south of USA to Japan (Distribution of Euphausia pacifica).

Feeding Most krill are herbivorous, but some are omnivorous feeders. Adults migrate diurnally to the surface at night, to feed on the phytoplankton. They are exclusively filter-feeeders: water enters in a “filter” as the animal swims, and food is shoved forward to the mouth.

Reproduction Males produce spermatophores in the dilated terminal part of the sperms ducts, and transfer them to the female with the aid of the first abdominal appendages. The female stores the male’s sperm and releases it to fertilize her eggs, which appear as small bubbles in her feeding basket. Females can produce many sets of eggs (totaling more than 20 000) during the summer spawning season. Krill larvae emerge from their shells at depths of several hundred meters, where, safe from predators, they subsist on yolky materials. Eggs hatch as non-feeding nauplii and pass through protozoea, zoea, and postlarval cyrtopia stages.

Predators Their predators are mainly finfish and baleen whales (picture of krill: stomach content of Bryde whale). Krill are a large dietary proportion of many local finfish (hake, herring, rockfish, salmon) and if krill stocks should fall, finfish could be affected. Humans are also a predator. A emerging commercial krill fishery exists on the B.C. coast with a current annual limit of 500 tonnes. Krill in B.C. are harvested mainly as a feed supplement for both fish farms (gives salmon their ‘pink’ colour) and aquariums. In other areas of the world (e.g., Japan) they are also used for human consumption in limited quantities. Fresh, uncooked euphausiids have almost no taste. Frozen or dried krill develop a strong, rather discouraging flavor. They constitute the ocean’s richest source of protein and are rich in vitamins (especially vitamin A)

Biotic association Some organisms are associated with the Euphausia pacifica but it seems that few are identified. Some of the identified ones are cilliates attached to eggs of the krill, and the parasite Thalassomyces fagei that belongs to the family Ellobiopsidae (Protista (Incertae sedis))  and infests the euphausiids. The Ellopbiopsidae have been classified at various times as protistans, colorless algae, fungi, or protozoans. They are multinucleate protistans with reproductive structures outside the host (here Euphausia pacifica) and absorptive portions inside.  The organ of fixation has fine protoplasmic filaments, which are believed to absorb nutrients from the host. The parasite usually affects the maturation, molting, and growth of the Euphausia pacifica.

Traditionally, krill and other plankton have been captured with net tows. Now the use of bioacoustics allows for the detection of plankton at a much greater rate than net sampling, but does not provide any information about what species and what age classes are being sampled.
Domain Eukarya
Kingdom Animalia
Phylum Arthropoda
Subphylum Crustacea
Class Malacostraca
Subclass Eucarida
Order Euphausiacea
Family Euphausidae
Genus Euphausia
Species pacifica
Common Name: Krill

References
Kozloff, E. N. 1996. Marine Invertebrates of the Pacific Northwest. University of Washington Press, Washington, United States of America.Meglitsch, P. A. 1972. Invertebrate Zoology. 2nd edition. Oxford University Press, United States of America.Gomez Gutierrez, J. 2001.Non- identified parasite associated to Euphausia pacifica: Part I and Part
I

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. The original text for this file was written by Marie-Noelle Belanger-Levesque (Quec, Canada) PC Year 28

 

Cryptochiton stelleri: Gumboot Chiton

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gumbootchiton

Cryptochiton grazing on red filamentous algae.

 

Characteristics: Chitons are characterised by their eight calcareous plates that are embedded in their dorsal surface. The Gumboot Chiton is usually dark reddish-brown in colour. The tough girdle that completely overgrows the plates is bristly and leathery in texture. The chiton has a large muscular foot and feeds using the radula.

Diet: Chitons, like limpets, are grazers that feed using their rasping radula. The radula consists of two rows of sharp teeth that function by scraping algae and benthic diatoms off rock surfaces.

Reproduction: Chitons are dioecious, which means there are both male and female chitons. The male releases the sperm into the water as shown in the video above, and it is taken up by the females. Fertilised eggs are shed singly or in gelatinous strings. The eggs develop into trochophore larvae before they metamorphose into the adult chiton form.
Classification:
Domain Eukarya
Kingdom Animalia
Phylum Mollusca
Class Polyplacophora
Order Neoloricata
Family Acanthochitonidae
Genus Cryptochiton
Species stelleri
Common Name: Gumboot Chiton

gumchiton1

In one section of the video linked below,  a very rare sequence is shown. A male Gumboot Chiton on the end of the docks at Race Rocks was shedding his gametes into the water. This was observed by our divers on several consecutive days. in the spring of 2002

This video shows the gumboot chiton in several locations at Race Rocks. Note the gills under the mantle on each side of the large foot. Of particular interest is the rare sequence taken at one meter depth in the surging water right off the docks, showing a male shedding gametes into the water.

Locomotion: Chitons have a broad and flat muscular foot which functions in adhesion as well as locomotion. Chitons move slowly and gradually by waves of muscular activity called ‘pedal waves’. The plates fuction to help them attach onto curved surfaces of the rocky intertidal zone.

Predators: The chiton’s main predator is the sea star Pisaster ochraceous, which are common on the coasts of Vancouver Island, but rare at Race Rocks and certain species of octopus.

Longevity: Gumboot chitons can live for approximately 20 years and can grow up to 30cm.

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.

original by: Sarah Mason PC yr 28

Cliona celata: Boring Sponge–Race Rocks taxonomy

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cliona

Cliona celata: This closeup image was taken by Ryan Murphy in May 2010. Clicking on the image gives a very large magnification. Clicking on the image below gives a sample of that level of magnification.

Domain Eukarya
Kingdom Animalia
Phylum Porifera
Class Demospongiae
Order Hadromerida
Family Dysideidae, Tetilla
Genus Cliona
Species celata
Common Name: Boring sponge

Cliona celata is lobular in shape with wart like projections on it surface. This species is commonly found in colonies and the portions of the colony showing at the surface have projections appearing  as yellow in color. They are evenly distributed on the sponge and are inhalent and seive like. Below the surface, the Cliona celata shell may look like a honeycomb. Cliona celata is commonly referred to as the boring sponge because it bores into soft limestone, using an acid digestion technique thus forming systems of interconnecting chambers within the matrix of the substrate

The opened up hinge area of the Purple Hinged Rock Scallop. Calliostoma is the snail and Metridium is the anemone. G.Fletcher photo.

 

The sponge can also bore as a parasite into mollusc and barnacle shells. It is common on many of the purple hinged rock scallops that we see underwater at Race Rocks.

At Race Rocks, the boring sponge is commonly found around the Rosedale Reef area. Its exhibits a biotic association with the purple -hinge rock scallop (Hinnites giganteus ) . Below is a picture of a complete rock scallop with small yellow dots where the sponge is located.

Boring sponges are the small yellow dots on the outside of this live Rock Scallop

Boring sponges are the small yellow dots on the outside of this live Rock Scallop which measures 18 cm in diameter.

 

References: As of 2001

http://web.ucs.ubc.ca/csmecher/demospon.htm 

http://www.diveinfo.com/porifera

http://www.itsligo.ie/biomar/porifera/clicel.htm

Kozloff, Eugene.N, Keys to the Marine Invertebrates of Puget Sound, the San Juan Archipelago, and Adjacent Regions; University of Washington press, 1974.
Other Members of the Phylum Porifera 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.  Dec. 2001–Misozi Phiri PC year 27

 

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