View metadata, citation and similar papers at core.ac.uk brought to you by CORE

provided by University of Oregon Scholars' Bank

Phylum: patula Class: ; Order: Veneroida The flat razor (Dixon, 1789) Family:

Description Size—to 150 mm (5 ¾”) (Morris et al. 1980); One other species of Siliqua is found average size 41/2 x 2'1; adults over 40 mm farther south (to Monterey Bay): Siliqua (Coan and Carlton 1975). lucida, a small (to 40 mm) razor clam, lives in Color— smooth, brown, shiny, protected bay sands, has a truncate posterior lacquerlike. Exterior white, obscurely rayed, end, a vertical internal radial rib and with faint violet coloration; interior white, concentric brown bands on its exterior. Old tinged with violet and pink. bookslist S. patula variation nuttalli, with a Shell Shape—"smooth within and without” more oval shape, purple beaks and four hinge (Dixon 1789); elongate, rather cylindrical; teeth in the left valve, not two (Oldroyd 1924). length about 2 1/2 times width. Valves similar, There are other razor-shaped gaping at both ends. Beaks toward anterior besides the Solenidae. The Mytiiidae end. family Solenidae (Coan and Carlton () include some genera, Adula for 1975), (beaks in Siliqua sp. are subcentral; instance, which are long and cylindrical. toward the anterior, but not close to its). Adula is usually a boring species, however; it Posterior end round, shell very thin, sharp has a hairy posterodorsal slope (Coan and edged, profile thin (fig. 4). Carlton 1975), a very small anterior adductor Hinge Area—left valve with two cardinal and scar, and no hinge teeth. (Keen and Coan two lateral teeth; right valve with one cardinal 1974) Hiatellidae, including the , and one lateral tooth (fig. 2); a vertical or Panope, are large, quad-rate, gaping radial rib projects downward and anteriorly bivalves, without hinge teeth, and with nearly from hinge in both valves: Siliqua equal adductor muscle scars (Keen and Coan (Keen and Coan 1974) (fig. 2). 1974). Ligament—external, not on nymph (fig. 2). One long, cylindrical bivalve of the family —siphons short, fused except at very Psammobiidae, californianus, the tips (fig. 4); exhalant and inhalant openings jackknife clam, could be confused with ringed by tentacles. Siliqua. It too has nearly central beaks, is Young—oval outline until about 2.5 mm long about 21/2 times as long as wide, and gapes (Pohlo 1963): (with central beak, not at both ends. It never has the internal elongate). strengthening rib of Siliqua, however, and its ligament is seated on a nymph or projection Possible Misidentifications (as in Protothaca staminea, see plate). Solenidae are cylindrical, about 2 1/2 Tagelus is gray, has no lateral teeth, and has times as long as high, and gape at both ends. short siphons (Coan and Carlton 1975). It is One other local giitilut.t has beaks quite near found below Humboldt Bay, California, in the anterior end, not subcentrally in Siliqua: mudflats. sp. have an almost straight dorsal margin, a terminal beak, and one cardinal Ecological Information tooth in each valve (Keen 1971). Solen Range—Aleutian Islands to Pismo Beach, sicarius, the blunt razor shell, is found California; but uncommon in California occasionally in permanent burrows in mud or (Weymouth and Holmes et al 1931). muddy sand, ie both intertiaally and sub- Local Distribution—Coos Bay: Pt. Adams tidally (Kozloff 1974a). It is the species most spit near Bay mouth; usually on open coast. likely. to be confused with Siliqua patula. It Habitat—flat, open beaches with fine, clean lacks Silqua's interior vertical rib and multiple sand; in strong surf zone with aeration hinge teeth, and is 4 times as long as wide, (Anonymous 1968) No permanent burrow. not 21/2 times. (Keen and Coan 1974) Niche assumed farther south by the Pismo

Digitized 2010 – Last Updated 1979 – E-mail corrections to [email protected] clam, Trivela stultorum (Ricketts and Calvin prized food mollusk in the northwest; 1971). seagulls, ducks, perch, crab (Anonymous Salinity—full seawater. 1968). Temperature—lives in cold to temperate Behavior—known for its quick, efficient wsterc digging ability: it can bury itself in less than 7 Tidal Level—about - 1.0 ft. and lower (Kozloff seconds, and moves especially rapidly in the 1974a). second or "slosh" layer of sand (Anonymous Associates—olive Olivella biplicata, 1968). Digging accomplished by ability of the caprellid amphipods, polychaetes, including anchor-shaped foot to change shape. Extra- Ophelia. Commensal nemertean ordinary muscle capacity and the Malacobdella grossa occurs in up to 80% of displacement of body fluids are responsible the clams (fig. 1a). for this (Pohlo 1963). Digging is vertical, sometimes angled toward the sea; very little Quantitative Information horizontal movement. Abundance—can be very abundant in certain local areas; populations move and fluctuate, Literature Cited due partly to storms, surf. Once harvested commercially along northwest coasts. 1. ANONYMOUS. 1968. Invertebrate Unrestricted digging severely harmed Fisheries, p. 35-49. Department of populations (Weymouth and McMillin 1931): Fish and Wildlife, Oregon State down-ward trend began around 1925. University, Corvallis, OR. Densest near mean low water (Anonymous 2. COAN, E. V., and J. T. CARLTON. 1968). 1976 Oregon total harvest 2,211,000 1975. Phylum Mollusca: Bivalvia, p. clams (Link 1977). 543-578. In: Light's manual; intertidal invertebrates of the central California Life History Information coast. S. F. Light, R. I. Smith, and J. T. Reproduction—high fecundity, high mortality Carlton (eds.). University of California (Anonymous 1968). Separate sexes; eggs Press, Berkeley. and sperm discharged into sea, fertilization by 3. DIXON, G. 1789. A voyage around the chance; 6-10 million eggs can be produced by world. George Goulding, London. a female. Spawning activated by minimum 4. KEEN, A.M. 1971. Sea shells of water temperature of 13°C (Fraser 1936). tropical west America; marine 86% of third year clams (10 cm long) mature mollusks from Baja California to Peru. or maturing (Queen Charlotte Island) (Fraser Stanford University Press, Stanford. 1936). Mass spawning late May or June 5. KEEN, A. M., and E. COAN. 1974. (Washington): occasionally huge sets of Marine Molluscan Genera of Western young. Larval stage 8 weeks; larvae free North America: An Illustrated Key. swimming but stay close to sand. After Stanford University Press, Stanford, metamorphosis, size of wheat grain or California. smaller; to 1.5 cm by end of growing season 6. MORRIS, R. H., D. P. ABBOTT, and (December, Washington) (Anonymous 1968). E. C. HADERLIE. 1980. Intertidal Growth Rate—3½ years to legal size of 4 invertebrates of California. Stanford 1/2" (11.5 cm) (Washington), where University Press, Stanford, California. grow rapidly, do not reach a large final size or 7. OLDROYD, I. S. 1924. Marine shells live as long as they do in Alaska (Weymouth of Puget Sound and vicinity. University and Holmes 1925). Growth rate slows after 10 of Washington Press, Seattle. cm size reached (Weymouth and Holmes et al 8. POHLO, R. H. 1963. Morphology and 1925); growing seasons show as wide brown mode of burrowing in Siliqua patula areas between rings, which are annual. and Solen rosaceus (Mollusca: Mortality in young probably 99%; greatest Bivalvia). The Veliger. 6:98-104. losses from storm movement (Anonymous 9. WEYMOUTH, F. W., and H. B. 1968). HOLMES. 1925. Growth and age at Longevity— maturity of the , Food—a of planktonic diatoms. Siliqua patula (Dixon). Bulletin of the Predators—man probably the most highly Digitized 2010 – Last Updated 1979 – E-mail corrections to [email protected] United States Bureau of Fisheries. 46:545-567.

Digitized 2010 – Last Updated 1979 – E-mail corrections to [email protected]

Digitized 2010 – Last Updated 1979 – E-mail corrections to [email protected]