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Bivalvia & Cephalopoda
Bivalvia
Species Encountered (Bivalves)
Chlamys rubida(Pacific pink scallop)
Mytilus californianus(California mussel)
Cephalopoda
Species Encountered
(Cephalopods)
Enteroctopus doflieni(giant Pacific octopus)
ReferencesWebpage created by Timothy Dillavou on 05-23-2007
Welcome to the home of Bivalvia and Cephalopoda. My name is Tim Dillavou and these pages are devoted to giving some background information on bivalves and cephalopods. They will also give some more detailed information on a few species I encountered during a marine ecology class at University of Washington-Tacoma during the spring of 2007.
BivalviaKingdom: animalia Phylum: mollusca Class: Bivalvia Characteristics: • Bivalve refers to having a shell with two halves or valves.• All bivalves have rigid shells to provide support for their soft bodies. • Bivalvia is the only molluscan class characterized by the absence of a radula.• Live:• Marine or freshwater• In or on top of sediment (epifaunal or infaunal)• Life span varies • Size 2mm to over 4 feet (giant clam of the south pacific)Feeding/Respiration: • Most are filter feeders defined by a gill structure• Some are scavengers or predators• consume phytoplankton and other tiny organic matter that flows through their gills. • gills function both in respiration and in straining out food particles.• mussels can filter 10-15 gallons of water per day.Locomotion:• muscular "foot" used for burrowing, or swimming (razor clams)• some use foot (byssal threads) for attaching to attaching to substrate (blue mussels)Reproduction:• externally when eggs and sperm are released into water• female may spawn millions of eggs in her lifetime. Senses:• In many bivalves, the mantle margin has a sensory function and often possesses rows
of parallel tentacles with tactile and chemosensory cells. In some species, the siphon tips may also possess such tentacles.
Species Encountered
Chlamys rubida(pacific pink scallop)
Mytilus californianus(California mussel)
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Crassostrea gigas (Japanese oyster)
Tresus nuttalli (pacific gaper)
Species Encountered(Bivalves)
Scientific name Common name Found Observations
Chlamys rubida Pacific pink scallop Friday Harbor (otter trawl) sponge covering one side, ears unequal size, swim
Clinocardium nuttalli Nuttalli’s cockle Fox Island & Willapa Bay oval shell, light brown, found at 12” depth
Modiolus modiolus Horse mussel Friday Harbor (otter trawl) brownish/black shell,
Size: 5’’ long
Mytilus californianus California mussel Friday Harbor (Cattle Point & Argyle Point),
Olympic Coast (Salt Creek)
bluish/black, attached to low rocks in colonies. rounded ridges on shell
Mytilus trossulus Bay mussel Point Defiance (floating dock)
Fox Island
smooth wedge shaped shell, attached to pilings w/byssal threads
Crassostrea gigasJapanese oyster Fox Island
Friday Harbor (False Bay)
irregular ridged shell, grayish/white
Ostrea lurida Native oyster Fox Island whitish gray
Pododesmus macrochisma
Rock oyster Point Defiance (floating dock)
Friday Harbor (Salt Creek)
jingle shell, hole in middle of lower shell, grayish
Tresus nuttalli Pacific Gaper Willapa Bay
Friday Harbor (False Bay)
siphon: yellowish/tan, gaper pea crab inside clam
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Chlamys rubida(Pacific pink scallop)
Description: • prominent ribs on each valve • grows to about 6 -7 cm long.• swim when threatened• many eyes around the outside, which
perceive light and direction. • One side of shell is covered with a
symbiotic sponge. Geographical Range: • Alaska to San Diego, CA; uncommon S
of Puget Sound. Depth Range: • low intertidal to 300 m; mainly subtidal Habitat:• rocky or gravel/mud bottoms. Life span: • up to 6 years. Reproduction:• externally when eggs and sperm are
released into waterHumans uses:• harvested by recreational & commercial
fishermen because highly desirable seafood.
Photos by Hannah Julich, May 2007back
Mytilus californianus(California sea mussel)
Description: • color: bluish/ black, concentric growth lines• shell to about 8 inches longGeographical range:• Alaska to southern Baja CaliforniaDepth Range:• mainly in intertidal zone on outer coastHabitat:• Abundant, on surf-exposed rocks and pier
pilings in colonies for protectionFeeding:• Filter feeder, prefer to eat fine organic
material and plankton Life span:• 10-100 yearsReproduction:• Male releases sperm into water and enters
female when water is siphoned over gills
Photo by Dave Cowles, Little Corona del Mar, CA March 2005
Photos by Bonnie Becker 2007
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CephalopodaKingdom: animalia Phylum: mollusca Class: cephalopodaTwo subclasses: •Coleoidea: squid, cuttlefish, and octopus •Nautiloidea: nautiluses Characteristics: •A funnel derived from the molluscan foot, circumoral arms that are probably derived from the molluscan head, chitinous beaks Habitat: •all marine, In all seas at all depths, Octopuses are solitary living in cracks and crevices but squid have been known to swim in large groupsLife span:• 1-3 years (except for nautilus up to 15 yrs)Feeding:• carnivores: crustaceans, fish, gastropod molluscs Respiration: •gills Locomotion: •walk with use of tentacles (octopus), lateral fins to swim (cuttlefish), jet propulsion (squids almost use exclusively) Shell/Skeleton: •Octopus- absent, squid- pen, cuttlefish- cuttlebone, nautilus- external Reproduction: •Coleoidea - lay hundreds to half a million eggs, Octopus-male typically dies after mating and female dies after guarding eggs•Nautiloidea- lays a few eggs each yearSenses: •eyes similar to humans (except for nautilus), touch, storage of chemical info for taste and texture Special notes: •change color, texture, and shape, very intelligent back
Species Encountered(Cephalopods)
Scientific name Common name Found Observations
Enteroctopus doflieni
Giant Pacific octopus
Olympic coast (Salt creek), Seattle aquarium
Only tentacle found at Salt creek (still changing color & suctioning)
Enteroctopus doflieni(giant Pacific Octopus)
Description: • largest species in the world, up to 400
lbs and 25 feet arm spanGeographical range: • Pacific ocean• common in Puget SoundDepth Range: • intertidal to 750 mHabitat:• rocky crevices Feeding:• crustaceans, mollusks, fishLife span:• 3-5 yearsReproduction:• female lays between 20,000 to 100,000
eggs and tends the eggs until hatched and then dies
Human uses: • food, display in aquariums, and for use
as bait in other fisheries
Picture by Greg Gilbert The Seattle Times, 2003back
Picture by Bonnie Becker, 2007
References
• The University of Arizona College of Agriculture and Life Sciences website accessed on 03-31-2007 http://tolweb.org/tree/phylogeny.html
• State of Washington website accessed on 04-02-2007 http://depts.washington.edu/natmap/mollusks/3bivafile.html • Bermuda Institute of Ocean Sciences website accessed on 04-03-2007 http://www.thecephalopodpage.org/
• Smithsonian National Zoological Park website accessed on 04-03-2007 http://nationalzoo.si.edu/Animals/Invertebrates/Facts/cephalopods/
• State University of New York College at Cortland website accessed on 03-31-2007 http://www.cortland.edu/
• University of Michigan Museum of Zoology website accessed on 04-04-2006 http://animaldiversity.ummz.umich.edu/site/accounts/information/Bivalvia.html
• University of Hawaii at Manoa website accessed on 04-04-2007 www.soest.hawaii.edu
• American Society of Limnology and Oceanography website accessed on 04-04-2007 www.aslo.org
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