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
The 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 controlwebcams.
Purple Urchins and Californianus sp mussels at a “zero” level tide on the west side of Great Race Rocks. July 2000
The purple sea urchin is about 10 cm. across, spines up to 2cm. and is bright purple. Its body “skeleton”, called the test, is shell like with bumps and holes from which the moveable spines and tube feet extend .The spines are used for protection, movement and for trapping drifting algae. It has a claw like mouth with 5 teeth-like plates. It is composed of over 60 shells and is called Aristotle’s lantern and is located on the underside or oral side of its body. The anus and the genital pores are on the aboral side of the sea Urchin.
In February, 2004 we had a note from CECIERJ requesting permission to use our video of the purple sea urchin in media being prepared for their undergrad distance learning courses. By offering these courses, the consortium CEDERJ contributes to bringing high quality free education to the inner cities of the Rio de Janeiro State. As well as permitting such use of our resources, we have added for them, an introduction by one of our Brazilian students, Rita who helped us make this video in Portuguese about the Sea Urchins and Echinoderms..
Diet: The Sea Urchin feeds on algae, plankton, kelp, periwinkles, and occasional tiny barnacles or mussels.
They are eaten by crabs, sunflower stars, snails, sea otters, some birds, fish, and people.
Reproduction: Fertilization in Sea Urchin is external, the female release several million tiny, yellow jelly-coated eggs at a time. The gametes join the water column as planktonic forms .
Behaviour: Although they often live in sheltering holes that they have worn in the rocks and they have also been observed to makes holes in solid steel, this behaviour is not evident at Race Rocks. Most of them live in shallow water here, They move surprisingly fast on their tube feet and spines. Moving their feet by a hydraulic water vascular system which creates suction in the end of the foot by pulling water out of the madreporite. They can also regrow broken spines.
The following images show the structural features on the test of a dead purple sea urchin. The image was produced by scanning.
This image shows the aboral view of a purple sea urchin.The dark patch in the middle is the anus. These were dead specimens.Thus the spines are missing.
Domain Eukarya
Kingdom Animalia
Phylum Ecinodermata
Class Echinodea
Order Echinoida
Family Strongylocentrotidae
Genus Strongylocentrotus
Species purpuratus
common name Purple Sea Urchin
The lower image shows the oral view of a purple sea urchin. The hole in the middle is its mouth with the sharp edges its 5 teeth. Note the pentaradial symmetry.
Emily finds a partially albino (pinto?) Parastichopuswhile diving near Church Island… just up the Strait from Race Rocks.
DESCRIPTION:
The California Sea Cucumber grows up to 50cm long. They are the largest cucumbers in B.C. waters. They range in colours from red in juveniles to brown or mottled brown, with all white individuals occurring rarely. They are covered on the dorsal side with flesh coloured papillae, and on the ventral side by tube feet. A circle of peltate feeding tentacles surround a subterminal mouth, directed ventrally at the anterior end. Oxygenated water is forcibly pumped into the sea cucumber’s respiratory trees in several successive inhalations, and then deoxygenated water is forcefully expelled. Eye-witness accounts have noted small fish being expelled with this force of water, perhaps living in symbiosis with the California sea cucumber.
RANGE:
Gulf of Alaska to Cedros Island, West of Lower California. Intertidal to 249m. Common on mud, gravel, shell, rock rubble or solid bedrock, from exposed coast to sheltered inlets. Greatest densities occur in quieter waters where organic sediments settle on hard surfaces. Harvesting of Sea Cucumber is also done by divers, throughout their range.
FEEDING, BEHAVIOR, AND BREEDING:
Sea cucumbers feed as they move along the bottom, traveling up to a maximum of 3.9m a day. They gain nutrition from organic material in sediment, mostly form bacteria and fungi. California Sea Cucumbers cease feeding and become dormant from September to early March. Once they reach maturity at four years of age, they will migrate to shallow water to spawn from late April to August, although this timing varies with location. Fertilization takes place in open water. Free swimming larva feed on plankton for 35-52 days before settling to the bottom. Parastichopus californicus has few natural predators. Sunflower starts sometimes eat them, and the sea cucumber reacts strongly by rearing back and flexing violently to avoid being eaten. They are harvested commercially in B.C., Washington, and Alaska for meat, and limits have been set for the amount that may be caught. When disturbed, as other sea cucumbers, it will contract and squirt a powerful stream of water from its posterior end. Five pairs of muscle bands which run the length of the body help this organism in contracting and escape from sea stars. Perhaps one of the most interesting features is this organisms ability to regenerate new organs for winter after expelling them during its dormant phase. It seems there is controversy as to whether sea urchins expel or reabsorb their organs. Recent evidence cited by Philip Lambert of the RBC museum in Victoria(1997) indicates that the sea cucumbers reabsorb their organs.
FURTHER INFORMATION NEEDED:
-further study at Race Rocks of commensal fish living in respiratory tree
-behaviour studies
-colouration, how long it takes to occur in full pigmentation, as a white individual found near Race Rocks has recently begun to change tan colour–later development?
-mechanism of absorbing/ejecting and regenerating organs
WEBSITE LINKS TO SEA CUCUMBERS:
Sea cucumber fishery – Pacific Region
http://www.pac.dfo-mpo.gc.ca/ops/fm/shellfish/Sea_Cucumber/biology_cucumber.htm
A paper by Phil Lambert on Sea Cucumber Taxonomy
http://rbcm1.rbcm.gov.bc.ca/nh_papers//taxing.html
REFERENCES CITED:
Carefoot, Thomas (1977), Pacific Seashores : A Guide to Intertidal Ecology
Lambert, Philip (1997), Sea Cucumbers of B.C., Southeast Alaska and Puget Sound
Morris, Abbott, Haderlie (1990), Intertidal Invertebrates of California The 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 controlwebcams. – Sarah Trefry Dec 2001 (PC)
Lined chitons are seen frequently by divers in the 5-15 meter depth at Race Rocks. Their color is highly variable, some being a turquoise colour while others are brown with white markings on some of the shell segments as noted on those in this video clip. Observe in particular, the patches of grazed Lithothamnion sp. , the pink encrusting algae.
Characteristics:
Tonos(stretched/braced) Cell,lineatus(lined/marked with lines).
The lined chiton eats the surface layers of this encrusting algae, including the film of diatoms and other small organisms on it.
All chitons have a muscular foot for locomotion, a complete digestive tract from the mouth to the anus, a calcium carbonate shell with 8 overlapping plates. This is produced by the mantle, where organs are suspended in coelom. A gill extracts oxygen and disposes waste, a chiton exposed to air consumes only 73 percent of the amount it does when submerged. It remains in oxygen debt until re submersion. Even though the body has bilateral symmetry, the gill numbers on both sides may very well be irregular, asymmetrical.
Physical Description: The lined chiton- Tonicellalineata -covered by 8 smooth plates,. Endless colour variations exist. The girdle around the plates is smooth and leathery, often with a row of lighter spots or bands. Size up to 5 cm long.
It is brightly colored, having a zigzagging dark black/ brown lines over a background of yellow, orange, pink, orchid, and lavender predominate. This aids in its camouflage around the Lithothamnion coralline algae, where it is usually found. Geographical Range: Aleutian Islands to San Miguel Island, CA, Sea of Okhotsk, Northern Japan Habitat: They live on rocks covered with coralline algae that are in the low intertidal or subtidal zone. They can also be found in urchin burrows in the rock. Feeding: They eat encrusting coralline algae. Predators:Predators of this invertebrate are sea stars, Pisaster ochraceus and Leptasterias hexactis. Harlequin ducks, and the river otters.. Reproduction: Dioecious broadcast spawners. Spawning occurs in the spring. The males release their sperm into the water while exhaling waste water. Females release a stream of green eggs. Larvae metamorphose into juveniles approximately 12 hours after having settled on coralline algae. Adaptations: Larval development stops unless the larva settles on coralline algae, which is its food source. This alga also acts as camouflage, as the chiton is often of the same colour.
Possible Further Studies: The behavior in different depths. The reproduction cycle of the lined chitons.
Kingdom Animalia
Phylum Mollusca
Class Polyplacophora
Order Neoloricata
Suborder Ischnochitonina
Family Ischnochitonidae
Genus Tonicella
Species lineata
Common Name lined chiton
Ecology and reproductive biology of Tonicella lineata (Wood, 1815)(Mollusca-Polyplacophora), by JR Barnes, 1972
The larval settling response of the lined chiton Tonicella lineata, by J. R. Barnes and J. J. Gonor, MARINE BIOLOGY, Volume 20, Number 3, page 259-264, 1973
Andy Lamb and Bernard P. Hanby, Marine Life of the Pacific Northwest, Harbour Publishing p. 176
Adam Sedgwick , Magazine: Proceedings of the Royal Society of London, Vol. 33, (1881 – 1882), pp. 121-127 Morris, R.H. et al. Intertidal Invertebrates of California. (Stanford: Stanford University Press, 1980)
The 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 controlwebcams.
During a presentation to the ETC conference at the United Nations School in New York in the spring of 2001, we tried out the underwater audio link from DIVELINK . An audio signal is relayed by SONAR for Ryan to a receiver near the docks. This receiver was connected to the audio input on the G3 laptop computer and to the shore tender as well. Both voices could be carried by the Sorenson Broadcaster first by wireless AirPort and then onto the internet. In this way we were able to communicate from underwater in the Pacific Ocean live by internet to the Altlantic coast. In this video, Ryan Murphy, a student at Pearson College, operates the device and the camera was operated by Jean-Olivier Dalphond, also a student at the college.
Characteristics: Tonos (stretched/braced) Cell,lineatus(lined/marked with lines).
The lined chiton eats the surface layers of this encrusting algae, including the film of diatoms and other small organisms on it.
All Chitons have a muscular foot for locomotion, a complete digestive tract from the mouth to the anus, a calcium carbonate shell with 8 overlapping plates. This is produced by the mantle, where organs are suspended in coelom. A gill extracts oxygen and disposes waste, a chiton exposed to air consumes only 73 percent of the amount it does when submerged. It remains in oxygen debt until re submersion. Even though the body has bilateral symmetry, the gill numbers on both sides may very well be irregular, asymmetrical.
Physical Description: The lined chiton, Tonicellalineata is covered by 8 smooth plates,. Endless colour variations exist. The girdle around the plates is smooth and leathery, often with a row of lighter spots or bands. Size up to 5 cm long.
It is brightly colored, having a zigzagging dark black/ brown lines over a background of yellow, orange, pink, orchid, and lavender predominate. This aids in its camouflage around Lithothamnion, the coralline algae, where it is usually found. Geographical Range: Aleutian Islands to San Miguel Island, CA, Sea of Okhotsk, Northern Japan Habitat: They live on rocks covered with coralline algae that are in the low intertidal or subtidal zone. They can also be found in urchin burrows in the rock. Feeding: They eat encrusting coralline algae. Predators:Predators of this invertebrate are sea stars, Pisaster ochraceus and Leptasterias hexactis. Harlequin ducks, and the river otters.. Reproduction: Dioecious broadcast spawners. Spawning occurs in the spring. The males release their sperm into the water while exhaling waste water. Females release a stream of green eggs. Larvae metamorphose into juveniles approximately 12 hours after having settled on coralline algae. Adaptations: Larval development stops unless the larva settles on coralline algae, which is its food source. This alga also acts as camouflage, as the chiton is often of the same colour.
Kingdom: Animalia
Phylum: Mollusca
Class: Polyplacophora
Order: Neoloricata
Suborder: Ischnochitonina
Family: Ischnochitonidae
Genus: Tonicella
Species: lineata
Common Name: lined chiton
Interesting Possible Further Studies:
The behavior in different depths.
The reproduction cycle of the lined chitons.
References:
http://www.wallawalla.edu/academics/departments/biology/rosario/inverts/Mollusca/Polyplacophora/Tonicella_lineata.htmlEcology and reproductive biology of Tonicella lineata(Wood, 1815)(Mollusca-Polyplacophora), by JR Barnes, 1972The larval settling response of the lined chiton Tonicella lineata, by J. R. Barnes and J. J. Gonor, MARINE BIOLOGY, Volume 20, Number 3, page 259-264, 1973http://wikis.evergreen.edu/marinelife1011/index.php/Tonicella_lineataAndy Lamb and Bernard P. Hanby, Marine Life of the Pacific Northwest, Harbour Publishing p. 176Adam Sedgwick , Magazine: Proceedings of the Royal Society of London, Vol. 33, (1881 – 1882), pp. 121-127
Morris, R.H. et al. Intertidal Invertebrates of California. (Stanford: Stanford University Press, 1980)
The 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 controlwebcams.
Shade Preference in Sub-tidal populations of Dorid Nudibranchs: an Analytical Rebuttal
Ryan M. J. Murphy November, 2000
A Submission for partial fulfillment of the requirements of the International Baccalaureate
PURPOSE:
The purpose of this investigation was to evaluate the claims of H.L. Geiger and A.R. Holyoak (1996) that adult dorid nudibranchs displayed a distinct shade preference during laboratory test runs, and then to analyse their conclusions.
INTRODUCTION:
Dorid nudibranchs, oval or ellipsoid in general shape, are dorsoventrally flattened. Protruding from their backs are two sets of structures. Anteriorly is a pair of rhinophores, chemosensory antennae that often have numerous folds and lamellae (or ridges) that serve to increase the sensitive surface area. This is their primary sense organ. More posteriorly are situated the flowerlike, branchial plumes (or gills). Dorids differ from the other main division of nudibranchs, the Aeolids, in that they have no ceratan extensions[1], but rather small papillae or no skin protuberances at all.
(from Morrow, 2000)
Nudibranchs are useful to marine ecologists as they are indicator species, that is, they can be used as early indicators of environmental change, such as degradation, to a community or ecosystem (Pidwirny, 2000). Nudibranchs and other opisthobranchs are useful to neurologists as well. Anisodoris nobilis in particular has been utilised for neurophysiological experiments because of its neurons that are many times larger than human neurons (Smallwood and Rogers, 1908). Also, since nudibranchs have relatively few neurons, neurologists can use nudibranchs to analyse the process by which neuromodulation controls bodily functions to a greater extent than is possible in any vertebrate circuit (Katz, 2000).
Nudibranchs are opisthobranchs, meaning they belong to a group of marine gastropod molluscs of the order Opisthobranchia, characterized by gills, a shell that is reduced or absent, and two pairs of tentacles. Opisthobranchs are simultaneous hermaphrodites, meaning that a single individual has both the male and female gonads (testis and ovary) to make sperm and eggs, as well as the external appendages for the transmission of these sex products by copulation. The final products in copulation of nudibranchs are resilient egg ribbons (Hurst, 1967) with large surface area-to-volume ratios, which are deposited during all seasons of the year. Egg ribbons of the Archidoris montereyensis nudibranch were studied by Biermann et al. (1992), who analysed the effects of solar radiation and other environmental factors on egg deposition site and embryo survival. Biermann et al. (1992) found that A. montereyensis preferentially laid their eggs underneath macroalgal shelter. In its natural habitat and in controlled laboratory conditions, they went on to determine that solar radiation arrested embryo development in tests that exposed the egg ribbons to direct sunlight in a shallow, water-cooled trough. Solar radiation was found to directly or indirectly limit the distribution of nudibranchs and their development in shallow water (Biermann et al., 1992). Biermann et al. proposed that adult dorids may actively select shaded areas to deposit their egg ribbons, an idea forming the basis for a more recent study of dorid nudibranch behaviour (Geiger and Holyoak, 1996).
eiger and Holyoak hypothesised that A. montereyensis adults’ preference to lay egg ribbons in shaded conditions was a direct result of natural selection against offspring of individuals that deposit egg ribbons in unshaded areas (1996). In addition, it was hypothesised that the differential survival of embryos as demonstrated by Biermann et al. (1992) might have an evolutionary effect on reproductive ecology (Geiger and Holyoak, 1996). Time trials conducted in an artificially shaded tank during the late spring involving 3 to 16 specimens of the same species showed that between 83.3 and 100% of the nudibranchs studied preferred shaded conditions to light (Geiger and Holyoak, 1996). Geiger and Holyoak used A. montereyensis specimens from piers at Friday Harbour on San Juan Island (see Friday Harbour, Figure 2), similar to the population studied by Biermann et al. (1992) at Argyle Creek on San Juan Island.
Figure 2: San Juan Island
Figure 3: Pedder Bay-Race Rocks Region
Figure 3: Pedder Bay-Race Rocks Region The initial purpose of this investigation was to determine if the shade preference as elucidated by Geiger and Holyoak in A. montereyensis, D. sandiegensis, and T. catalinae was present in other dorid nudibranch species. Five species of nudibranch were chosen for this experiment (see Appendix A): Archidoris montereyensis (MacFarland, 1966), Anisodoris nobilis (MacFarland, 1905), Diaulula sandiegensis (Bergh, 1879), Acanthodoris hudsoni (MacFarland, 1905)and Cadlina luteomarginata (MacFarland, 1905). A. montereyensis and D. sandiegensis were used as a comparison to the Geiger and Holyoak experiment. Cadlina luteomarginata, Acanthodoris hudsoni,and Diaulula sandiegensis were chosen for their local abundance, as well as to determine whether there are behavioural differences between dorids generally more common in the low inter-tidal ranges (i.e. A. hudsoni, A. montereyensis, and D. sandiegensis) and those more common in the subtidal range (i.e. C. luteomarginata and A. nobilis) (Morris et al., 1983). Upon initial tests with A. montereyensis, it became clear that shade preference of other dorids could not be the focus of the investigation, for as Geiger and Holyoak found a negative relationship between dorid movement and light intensity, my preliminary work showed the contrary. The obvious question then arose: Why the population of A. montereyensis and D. sandiegensis specimens being tested did not express shade preference as the Friday Harbour populations did. Subsequent analyses were designed to verify these results, and to help explain this difference.
All five nudibranch species used in this study were collected at Great Race Rocks, 48o17’45” N, 123 o31’50” W (see Figure 3) at depths between 6 and 12 m, subtidal range. Initial time trials were conducted in mid-May, 2000, and all secondary trials were conducted in late October and early November 2000.
This video was shot by the team of Pearson College divers while practicing for the live webcast for the QuickTime Live Conference in California- Oct 2000 .
On the 4th of October, a 5 member diving team brought the camera to West Race Rock to film the marine life there. Along with Red Sea Urchins (Strongylocentrotus franciscanus), Plumose Anemones (Metridium farcimen), and a Tiger Rockfish (Sebastes nigrocinctus) was a large school of Black Rockfish (Sebastes melanops). The camera crew for the dive was J.O. Dalphond, Hana Boye, and myself. Organism identification responsibility falls on me. Hinted streaming video time is 3 minutes 22 secs
My name is Ryan Murphy and I am a Year 26 Pearson Student from Newfoundland. I am doing the editing on this movie. I’m the diver with the blue snorkel signalling “OK” at the beginning. Garry, our Guru, is showing me how to do this in iMovie as this is my first movie, I hope you enjoy it.
In mid May 2000, this video was taken of some of the varieties of zooplankton found by diving on an ebb tide at the end of the docks on the North side of Race Rocks.
Return to the Race Rocks Taxonomy
The 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.
