Cryptochiton stelleri: Gumboot Chiton

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

Haliotis kamtschatkana: Northern Abalone–The Race Rocks Taxonomy

Cryptic Coloration of Abalone
Associated organisms with abalone.

Domain Eukarya
Kingdom Animalia
Phylum Mollusca
Class Gastropoda
Subclass Prosobranchia
Order Archaeogastropoda
Suborder Pleurotomariina
Family Haliotidae
Genus Haliotis
Species kamtschatkana
Common Name: Northern Abalone

Paulina and the PC Divers go in search of abalone for our population tagging program. The opportunity arises to demonstrate the escape response of the Northern Abalone, when it is presented with a Pycnopodia, the giant sunflower star.

Scott Wallace did research in 1997 and 1998 at Race Rocks with Pearson College divers. He studied the population dynamics of the Northern Abalone, Haliotis kamtchatkana. His research was done as part of a PhD thesis in Resource Management from the University of British Columbia in Vancouver. In May of 2000, he returned to Race Rocks for a dive with Garry and Hana and an interview with Stephanie Paine and Director Julia Nunes for the Discovery Channel. In this video he demonstrates the measurement technique he used in his research

Link to Abstract of Scott’s Paper
Wallace, Scott, S. 1999, Evaluating the Effects of Three Forms of Marine Reserve on Northern Abalone Populations in British Columbia, Canada. Conservation Biology, Vol 13 No 4, August, 1999, pages 882-887.
An article by Scott Wallace:
Out of Sight, Out of Mind, and Almost out of Time out of sight out of mind–mpa

 

 

 

n 1998, we began a long term research program, initiated by Dr. Scott Wallace, on the population dynamics of the Northern Abalone
(Haliotis kamtschatkana).

For several years, the Pearson College divers monitored the population. In this video, Pearson College graduate Jim Palardy (PC yr.25) explains the process.

Carmen Braden and Garry find a Northern Abalone exposed at low tide in June in the intertidal zone of the east side of Race Rocks. They talk about its adaptations and the problem of overharvesting which has resulted in the endangered status.

This abalone was filmed by Felix Chow as it was rasping off diatoms from the glass wall of the aquarium. A small tongue or radula scrapes the algae from the walls.

General information:

Northern or Pinto abalones (Haliotis kamtschatkana) belong to the class of mollusks having a shell that consists of one piece. The genus they belong to is Haliotis, which means “sea ear” and refers to the flattened shape of the shell.

abaloneshellDescription:

Pintos are the smallest abalones and they are commonly about 4 inches long, however the biggest individuals can grow as big as 6 inches long (12 cm). The shell is oval or rounded with a large dome towards one end; it is also irregularly mottled and narrow. The colour of the shell exterior is mottled greenish brown with scattered white and blue. The shell has a row of respiratory pores through which the abalone takes in water and filters dissolved oxygen from the surrounding water with its gills. Water that passes through the body leaves through the respiratory holes carrying away waster from the digestive system. Pinto abalones have from 3 to 6 open holes in their shells. The shape of these respiratory holes is oval and they are raised. The colour of the pinto abalones’ epipodium is mottled greenish tan or brown. The tentacles are thin and the colour of them can vary from yellowish brown to green. Abalones’ muscular foot has a strong suction power that permits the abalone to clamp tightly to rocky surfaces.

Habitat:

Pinto abalones have definite preferences in locations and habits. Pinto abalones range from Sit ka, Alaska to Monterey, California. The only member of the genus is likely to be found in the Puget Sound region., on the open coast of Vancouver Island and Washington. Farther south pinto abalones become strictly sub tidal. Pinto abalones can be found clinging to rocks in kelp beds along open coastal environments that have a good water circulation. Their habitat is between the low inter tidal zone and sub tidally down to 70 feet (18 meters depth).

Life cycle:

The life cycle of an abalone begins from an egg. Abalone female releases millions of eggs, but only about 1% (or even less) of the offspring survive the many challenges they have to face before maturity. The eggs turn into a free living larva and then after drifting with the currents about a week the abalone larva settles to the bottom and begins to develop the adult shell form.

Predators:

Abalone have many predators. They get eaten by other animals (crabs, lobsters, octopuses, starfish, fish and snails) and crushed to the rocks by strong waves. The sea otter was traditionally one of the most significant predators of abalones, although they have not yet moved into the Strait of Juan de Fuca, from the re-introduction several years ago to northern Vancouver Island.

Nutrition:

Pinto abalones, as all abalones, are herbivores. They use their large, rough radulas (“tongues”) to scrape pieces of algae and other plant material from the rock surfaces. The adult abalone feeds on loose pieces of algae drifting in water. Abalones prefer large brown algae; mainly different kind of kelps and seaweed. The colour banding on many abalone shells is caused by the changes in the type of algae that the abalone has eaten.

Threats:

Pinto abalones used to be subject to sports and commercial fishery . They suffered from over harvesting and habitat loss and poaching. There is now a permanent closure on all abalone fishing on the B.C. Coast. For the Pacific North West Coast First Nations People, the beautiful shells of abalone were used for jewelry and abalone also were a seafood delicacy. They occur sub tidally and only in remote areas.

See the Abalone measurement and statistics exercise at RaceRocks:
http://www.racerocks.com/racerock/research/abalone/abalonemeas.htm

See our abalone exercise for middle school.

References Cited:

Kozloff, Eugene N., Marine Invertebrates of the Pacific Northwest, University of Washington Press, Seattle and London, 1996.

Kozloff, Eugene N., Seashore life of the Northern Pacific Coast, University of Washington Press, Seattle and London, 1996.

Meglitsch, Paul A., Invertebrate Zoology; second edition, Oxford University Press, 1972.

Snively, Gloria, Exploring the Seashore in British Columbia, Washington and Oregon, Gordon Soules Book Publishers Ltd., Vancouver/London, 1981.

http://www.pacificbio.org/ESIN/OtherInvertebrates/NorthernAbalone/NorthernAbalone_pg.html ( available at this URL in 20101)

http://www.sonic.net/~tomgray/describe.html

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. Salla Vornanen, PC yr 27

 

Enteroctopus dolpheni: Giant Pacific Octopus: The Race Rocks Taxonomy

rmoctopus eye

Enteroctopus dolpheni: Giant Pacific Octopus: The advanced eye of a mollusc. Photo by Ryan Murphy

Getting up close and personal was one of the things that former Ecoguardian Ryan Murphy was able to do very well underwater.. Consequently he produced the following interesting images from underwater.

We frequently encounter Octopus while diving at Race Rocks. They blend in very well with the algae and can change colors rapidly. Often the best way to see them is to spot their large (1-2 cm) white suckers in a crevice or cave. According to the website below, “Although it is very unusual to find an individual over 45kg, one large individual captured just near Victoria in 1967 weighed 70 kilograms (156 pounds) and was almost 7.5 meters ( 23 feet ) from arm tip to arm tip.

Smaller animals occur occasionally in low intertidal pools on rocky shores, larger individuals generally subtidal to depths of 100m; along North Pacific rim from northern Asia to California;

One of the largest octopus species known, the largest specimen on record with a total arm spread of 9.6m and a weight of 272 kg; dorsal mantle length usually over 20 cm; weight sometimes exceeding 50 kg; body ovoid, with extensive skin folds, red to reddish brown above, pale below; ocelli absent; arms 3-5 times body length, lacking specialized enlarged suckers and large truncate papillae; hectocotylus large, about one-fifth the length of the third right arm; with 12-15 lamellae on the outer demibranch of each gill; gill lamellae 25-29; ink dark brown; eggs measuring 6-8 mm by 2-3 mm, planktonic larva with a single row of chromatophores on each arm; borne in capsules on long stalks, these entangled and cemented together to form long festoons.

The Giant Pacific Octopus, (Enteroctopus dofleini , Hochberg, 1998) was formerly classified as : Octopus dofleini (Wulker, 1910)

 

Giant Pacific Octopus frequently appear at Race Rocks in the subtidal waters. They are also seen occasionally washed up in the intertidal zone where they contribute to the energy flow of the gulls and eagles. This individual which had died recently in June 2002, became the subject of a webcast and an impromptu dissection on the shore.

Video on Octopus necropsy

Domain: Eukarya
Kingdom: Animalia
Phylum: Mollusca
Class: Cephalopoda
Order Octopoda
Suborder: Incirrata
Family :Octopodidae
Genus: Enteroctopus
Species: dofleini (Hochberg, 1998)
Common Name:  Giant Pacific Octopus
Although E.dofleini has been used extensively in laboratory studies, its natural history is still poorly known. The life cycle is thought to be 4-5 years. Eggs are laid throughout the year, though mainly in the winter, and development takes 5-7 months; hatching peaks in the early spring. The young are pelagic for a short period, probably about 1 month.

The three images above of a baby Octopus were taken in the intertidal zone near the docks by
Ryan Murphy in July 2004
.

The adults feed on crustaceans (shrimps and crabs), mollusks (scallops, clams, abalones, moon snails, and small octopuses, and fishes ( rockfishes, flat fishes, and sculpins). Large crabs are stalked and then caught with a sudden flick of one or more arms; empty crab carapaces, shiny shells, and bones often litter the entrance to a lair. The octopus takes smaller shrimps and fishes by slowly arching its body over a seaweed bed, then suddenly pouncing, and enclosing the area in a canopy formed by the web membrane that joins the basal parts of adjacent arms. The sensitive arm tips are then inserted into the impounded area to search for food.

  • Two mesozoan parasites charactersictically occur in the kidneys of E. dofleini: Dicyemennea abreida and Conocyema deca.

This octopus is fed upon by seals, sea otters, dogfish sharks, lingcod, and man. It supports small commercial fisheries in Alaska, Canada, Washington, Oregon, and Northern California. Locally, it is also used by halibut fishers as bait.

Literature Cited:

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

Eugene N. Kozloff, Marine Invertebrates of the Pacific Northwest

octopus and diverLink to an assignment on Biodiversity submitted to us by
Shawna Millard Biology 202 at Bellevue Community College, Washington.

 

 

Return to the Race Rocks Taxonomy

This file is provided as part of a collaborative effort by the students, faculty and volunteers of Lester B. Pearson College .  This file was started by: Amanda Muscat PC yr 27, Dec. 2001.

Tonicella lineata: lined chiton–The Race Rocks Taxonomy

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- Tonicella lineata -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

  • References:
    http://www.wallawalla.edu/academics/departments/biology/rosario/inverts/Mollusca/Polyplacophora/Tonicella_lineata.html

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

http://wikis.evergreen.edu/marinelife1011/index.php/Tonicella_lineata

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)

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.

 December 2001 – Bassam( Jarbawi (PC year 27)

 

 

Tonicella lineata: the lined chiton

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.
linedchiton-1
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,  Tonicella lineata  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.html
    Ecology 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)

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.

Bassam Jarbawi (PC yr. 27)