Tag Archives: seastar

Solaster stimpsoni: Stripped Sun Star–The Race Rocks Taxonomy

Posted on by

This is a frame taken from the video beside. The blue color is because white light does penetrate to a depth of 8 metres, so only the parts of the picture that are illuminated from the video light show the true colors.. Note in the video how objects appear to change color when illuminated, but, they don’t actually do so. In the foreground is a broooding anemone , red with a band of babies at its girth. The pink coral is hydrocoral.

“Invertebrates at Race Rocks” is an introductory piece on a few of the invertebrate phyla. This was one of the first hinted streaming videos done by the Pearson College divers in April 2000. There is a good section on Soalaster Stimpsoni in the film. It was taken by Rowena and Shamsher on a Sony Digital camera, and edited by Hannah and Garry on a G4 Macintosh Computer using iMovie.

 

Physical Description
It has 8-12 arms, but usually it has 10 arms, which has length is about 23 cm. The diameter about 20 inches (51 cm). And the central disc about &Mac185; of total diameter. It&Mac226;s mouth just below the central disc. And, as the common sea star, it uses its tube feet which under main arms to move.

Global Distribution
This kind of sea star could be found at Bering Sea to Salt Point California (Trinidad Head, Sonoma Country, Kodiak Island and Oregon) and Pacific Northwest (Sunrise Beach and Gig Harbor).

Physical Description
It has 8-12 arms, but usually it has 10 arms, which has length is about 23 cm. The diameter about 20 inches (51 cm). And, as the common sea star, it uses its tube feet which under main arms to move.

Habitat
This sea star is possible to find at rocky bottoms but sometimes in sand or in the lowest zone.
Domain Eukarya
Kingdom Animalia
Phylum Echinodermata
Class Asteroida
Order Spinulosida
Suborder Eugnathina
Family Solasteridae
Genus Solaster
Species stimpsoni
Common Name: Stripped Sun Star, Sun Star, Stimpson’s
Feeding
This animal is a carnivore. It usually feed at sea cucumbers (the most favorite foods), tunicates, lampshells, sea pens, brachiopods, holothurians, sea squirts and nudibranch.

Predator
The predator of this animal is Sunflower Star ( Solaster dawsoni).

Reproduction
It reproduces sexually. It is breeding from February to March. Gametes are discharge into water. The eggs then become larvae and start to metamorphosis for about 40-50 days.

Interesting Thing
It can curl its arms up over its body to take on a spherical shape. This allows it to tumble across the seafloor in the along-shore currents.

References
Alaska Fisheries Science Center, Sun Sea Star Solaster Stimpsoni. Internet
British Columbia Creature Page. Internet
Edmonds Discovery Programs. Internet
Gotshall Daniel (1994) Guide To Marine Invertebrates. California
King Country (1999) Sun Star &Mac246; Solaster Stimpsoni. Internet
Lambert Philip (1965) Sea Star. Vancouver, Canada
Morris Robert, Donald A & Eugene H (1980) Interditial Invertebrates of California. California
Photo Gallery. Internet
Strathmann Megumi (1987) Reproduction And Development of Marine Invertebrates of The Northern Pacific Coast. Friday Harbour Laboratory
Verrill (1880) Solaster Stimpsoni. Internet
Yates Steve (1988) Marine Wildlife. Washington

 

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.

January 2006 Winda (PC year 32)

Hippasteria spinosa:The Spiny Sea star–The Race Rocks taxonomy

Posted on by

 

Spiny Stars are rarely seen by divers at Race Rocks. Ryan demonstrates one to the Colwood Elementary a school class

Description:

The Hippasteria spinosa is an uncommon, 5 armed, aboral surfaced sea star. Its most marginal plates have 2 spines and it has some conspicuous bivalved pedicellariae.

Its colour is orange to vermillion, which intensifies at the short, stalky arms (R/r=1.7 to 2.6) and becomes whiter near the mouth. Usually in the subtidal region at depths of 100 to 500 metres, it can sometimes be found on the beach. It is characterized by having all its plates covered with granules, giving it a spiny, STELLATE look.The mouth has 4 or 5 marginal spines and a slightly wider than high mouth (elipsis shape).

Habitat and region

Can be found from Kodiak Island to Southern of California and the Sea of Okhotsk and is more common around the west coast of Vancouver Island and other exposed coastal parts. It prefers muddy, shallow environments and can also be found in shell and rock.

References:
Taxonomy: Marine Invertebrates of the Pacific Northwest; Kozloff, Eugene, University of Washington Press, 1996 Edition, USA

 

Solaster dawsoni :Morning Sun star– The Race Rocks Taxonomy

Posted on by

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

Posted on by

 

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

Posted on by

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)

Henricia leviuscula The Race Rocks Taxonomy

Posted on by

 

Blood stars are seen frequently by divers in the 0-15 meter depth at Race Rocks. They are planktonic feeders.

Kingdom Animalia
Phylum Echinodermata
Class Stelleroidea
Sub Class Asteroidea
Order Spinulosida
Sub Order Leptognathina
Family Echinasteriade
Genus Henricia
Species Leviuscula
Common Name Blood Star

The Blood Star is characterized by its brilliant red or reddish-orange color. Its comparatively small and graceful its body is only 10 to 12 cm from the tip of one ray to the tip of the one across from it. It has an arm radius to 8.9 cm, usually less; its disk is small, its arms are long, tapering, and are usually five in name (sometimes four or six); it has an absent pedicellariae; its aboral surface has a tan to orange-red or purple color., often banded with darker shades, and bearing many groups of short spinlets arranged in a fine network.
Habitat: Common on protected sides of rocks, under rocks, and in caves and pools, more frequently where rock is encrusted with sponges and bryozoans, low intertidal zone, subtidal to over 400 m.

The sea star feeds on bacteria and other tiny particles, which are captured in mucus and swept to the mouth by ciliated tracts. It may also feed by applying the stomach to the surfaces of sponges and bryozoa.

Breeding habits in the sea star vary with size. Smaller females brood their eggs in a depression around the mouth formed by arching the arms. Larger females discharge eggs directly into the water and do not brood them. The sperm have spherical heads and the eggs are orange-yellow and yolky, and development is direct.

REFERENCES CITED:

1. Robert H. Morris, Donald P. Abbott, and Eugene C. Haderlie,Intertidal Invertebrates of California, 1980, Stanford University

LINKS:

http://elib.cs.berkeley.edu/photos/fauna/sci-invertebrate.html

http://enature.com/fieldguide/showSpeciesSH.asp?curGroupID=
8&shapeID=1072&curPageNum=9&recnum=SC0074

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.

 Dec 2001Tania Melendez (PC yr.27)