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Home , Ensis, Geoduck, Heterodonta, Olive snail, Pacific razor clam, Pharidae

Phylum: patula Class: ; Order: Veneroida The flat razor Family:

Taxonomy: The familial designation of this (see Plate 397G, Coan and Valentich-Scott has changed frequently over time. 2007). Previously in the , current intertidal Body: (see Plate 29 Ricketts and Calvin guides include S. patula in the Pharidae (e.g., 1952; Fig 259 Kozloff 1993). Coan and Valentich-Scott 2007). The superfamily Solenacea includes infaunal soft Color: bottom dwelling bivalves and contains the two Interior: (see Fig 5, Pohlo 1963). families: Solenidae and Pharidae (= Exterior: Cultellidae, von Cosel 1993) (Remacha- Byssus: Trivino and Anadon 2006). In 1788, Dixon Gills: described S. patula from specimens collected Shell: The shell in S. patula is thin and with in (see Range) and Conrad described sharp (i.e., razor-like) edges and a thin profile the same species, under the name (Fig. 4). Thin, long, fragile shell (Ricketts and nuttallii from specimens collected in the Calvin 1952), with gapes at both ends Columbia River in 1838 (Weymouth et al. (Haderlie and Abbott 1980). Shell smooth 1926). These names were later inside and out (Dixon 1789), elongate, rather synonymized, thus known synonyms for cylindrical and the length is about 2.5 times Siliqua patula include Solen nuttallii, the width. nuttallii. Occasionally, researchers Interior: Prominent internal vertical also indicate a subspecific epithet (e.g., rib extending from beak to margin (Haderlie Siliqua siliqua patula) or variations (e.g., and Abbott 1980). Siliqua patula var. nuttallii, based on rib Exterior: Both valves are similar and morphology, see Possible gape at both ends. The beaks are subcentral Misidentifications) (Oldroyd 1924). and toward anterior end, and the posterior end is round. Description Hinge: The hinge ligament is Size: Individuals up to 190 mm (Haderlie and completely external, and not seated on a Abbott 1980; Coan and Valentich-Scott 2007), nymph (Fig. 2). The left valve is with four with average size adults over 40 mm (Coan cardinal teeth, while the right valve is with two and Carlton 1975). (Fig. 2). A vertical or radial rib projects Color: is smooth, brown, shiny, downward and anteriorly from hinge in both and lacquer-like (Ricketts and Calvin 1952). valves (Siliqua, Keen and Coan 1974) (Fig. The shell exterior is white, obscurely rayed, 2). with faint violet coloration and the interior is Eyes: also white, but tinged with violet and pink Foot: The foot in S. patula projects to a (Haderlie and Abbott 1980). length that is one half the total shell length General Morphology: Bivalve mollusks are and has a muscular flap (Haderlie and Abbott bilaterally symmetrical with two lateral valves 1980). It aids in digging by anchoring within or shells that are hinged dorsally and the sediment and contracting such that the surround a mantle, head, foot and viscera body is pulled downward (Ricketts and Calvin (see Plate 393B, Coan and Valentich-Scott 1952) (see Burrow and Behavior). 2007). Solenid and pharid bivalves are Siphons: Siphons are short and fused at the burrowers and some species are quite fast tips, except at the very end (Haderlie and (e.g., Siliqua patula, see description in this Abbott 1980) (Fig. 4). The exhalant and guide). They have shells that are longer than inhalant openings are ringed by tentacles. wide and often razor-like at the opening edge

Hiebert, T.C. 2015. Siliqua patula. In: Oregon Estuarine Invertebrates: Rudys' Illustrated Guide to Common Species, 3rd ed. T.C. Hiebert, B.A. Butler and A.L. Shanks (eds.). University of Oregon Libraries and Oregon Institute of Marine Biology, Charleston, OR.

A publication of the University of Oregon Libraries and the Oregon Institute of Marine Biology Individual species: http://hdl.handle.net/1794/12920 and full 3rd edition: http://hdl.handle.net/1794/18839 Email corrections to: [email protected] Burrow: A fast burrower, S. patula uses its S. patula (< 55 mm in length) and has an foot to anchor and muscular contractions to internal rib that is vertical and narrow and a pull body downward. Individuals can posterior end that is truncate. It has been completely bury itself within seven seconds suggested that S. lucida are simply young S. (Ricketts and Calvin 1952) and the burrowing patula individuals (Hertlein 1961), but this is speed allows them to avoid the reach of many not yet known. Siliqua lucida lives in clam diggers. Burrowing behavior leaves a protected bay sands and has concentric slight dimple in the sand at the surface (not brown bands on its exterior. Although unlike a thumb imprint). There is no variations in S. patula have been permanent burrow, unlike the similar species synonymized, occasionally readers will find Solen sicarius (see description in this guide) references to S. patula var. nuttallii, which is (Haderlie and Abbott 1980). Individuals orient more oval shape, with purple beaks and four vertically within the sediment (see Fig 3, in the left valve, not two (Oldroyd Pohlo 1963; Haderlie and Abbott 1980). 1924). myrae and Siliqua altra are offshore species and E. myrae is has a shell Possible Misidentifications that is long and thin. Solenidae and Pharidae are two razor clam Only two species, in the Solen, families represented locally and pharid are reported locally in the Solenidae, they genera were recently placed in the former have an almost straight dorsal margin, a family (see previous editions of this guide). terminal beak, and one cardinal tooth in each They are both characterized by cylindrical valve (Keen 1971). Solen rostiformis (= S. shells that are about 2.5 times as long as high rosaceus, but see Pohlo 1963; von Cosel and gape at both ends. They have no dorsal 1992) has a thin shell that tapers and a margin ears (compare to Pectinidae, see periostracum that is lighter than S. sicarius; it Plate 394E, Coan and Valentich-Scott 2007), is light olive green to brown in color. Solen a hinge with ligament that is entirely external rostiformis is a pink shelled clam and its and dorsal, equally shaped adductor muscle siphons are annulated (and it can regenerate scars (compare to Mytilus trossulus, this them when disturbed, Pohlo 1963). It lives in guide), and shells that do not have prominent sandier situations than does S. sicarius radial sculpturing (Coan and Valentich-Scott (Coan and Carlton 1975). Solen sicarius, on 2007). The difference between the two the other hand, has a thick shell, a blunt families is that members of the Pharidae have posterior (‘the blunt ’) and a dark one shell valve with two cardinal teeth and the brown periostracum. Solen sicarius is found other with four, while the Solenidae have a occasionally in permanent burrows in mud or single cardinal tooth on each shell valve muddy sand (Kozloff 1974) and is the (Coan and Valentich-Scott 2007). Other local species most likely to be confused with razor-shaped besides the Solenidae Siliqua patula. It lacks an interior vertical rib such as the Mytiiidae include some genera and multiple hinge teeth, and is four times as (e.g. Adula) which are also long and long as wide, not 2.5 times, as in S. patula cylindrical. Adula (see A. californiensis, this (Keen and Coan 1974). Furthermore, the guide) are usually a boring species, however, profile in S. patula is much more oval, and having hairy posterodorsal slopes, a very not as cylindrical as in Solen sicarius. small anterior adductor scar, and no hinge One long, cylindrical bivalve of the teeth (Coan and Valentich-Scott 2007). family , californianus, , including the , the jackknife clam, could be confused with generosa have large, quadrate, gaping Siliqua patula. It too has nearly central bivalves, without hinge teeth, and with nearly beaks, is about 2.5 times as long as wide, equal adductor muscle scars (Keen and Coan and gapes at both ends. It never has the 1974). internal strengthening rib of S. patula, Four species are reported locally in however, and its ligament is seated on a the Pharidae. Siliqua patula has an internal nymph or projection (as in Protothaca rib that slopes anteriorly, a wide and tapering staminea, see plate). posterior end. Siliqua lucida is smaller than is gray, has no lateral teeth, and has short

Hiebert, T.C. 2015. Siliqua patula. In: Oregon Estuarine Invertebrates: Rudys' Illustrated Guide to Common Species, 3rd ed. T.C. Hiebert, B.A. Butler and A.L. Shanks (eds.). University of Oregon Libraries and Oregon Institute of Marine Biology, Charleston, OR. siphons (Coan and Carlton 1975). It is found Life-History Information below Humboldt Bay, California, in mudflats. Reproduction: Separate sexes with broadcast spawning and external fertilization. Ecological Information Females produce 6–10 million eggs. In Range: Siliqua patula was described from , all individuals spawn suddenly individuals collected near Coal Harbor, Cook and simultaneously near the end of May or Inlet, Alaska (Weymouth et al. 1926). Known early June, when water temperatures rise range includes Aleutian Islands to Pismo (e.g., 13˚C, Fraser 1936; Ricketts and Calvin Beach, California, but individuals are 1952; Haderlie and Abbott 1980). However, uncommon in California (Weymouth et al. spawning is not sudden or simultaneous in 1931). Alaska or , Canada, where Local Distribution: Coos Bay distribution at spawning occurs from July to August (Ricketts Pt. Adams spit near the mouth of the bay and and Calvin 1952; Bourne and Quayle 1970; usually on open coast. This species is more Breese and Robinson 1981, Lassuy and common in coastal regions with long stretches Simons 1989. Sperm morphology appears to of wide sandy beaches (e.g., Seaside, OR, characterize many veneroid taxa (see Fig. 2, Connolly 1995). Healy 1995). Habitat: Flat, open beaches with fine, clean Larva: Bivalve development, including sand in strong surf zone with aeration members of the , generally (Anonymous 1968; Haderlie and Abbott proceeds from external fertilization via 1980). This niche is occupied further south broadcast spawning through a ciliated by the Pismo clam, Trivela stultorum (Ricketts trochophore stage to a veliger larva. Bivalve and Calvin 1971). veligers are characterized by a ciliated velum Salinity: Collected at salinities of 30 or more, that is used for swimming, feeding and in full strength seawater. respiration. The veliger larva is also found in Temperature: Lives in cold to temperate many gastropod larvae, but the larvae in the waters. two groups can be recognized by shell Tidal Level: Low intertidal to shallow subtidal morphology (i.e. -like versus clam-like). (Haderlie and Abbott 1980), about - 0.3 In bivalves, the initial shelled-larva is called a meters and lower (Kozloff 1993). D-stage or straight-hinge veliger due to the Associates: Known associates include the “D” shaped shell. This initial shell is called a , biplicata, caprellid prodissoconch I and is followed by a amphipods, and polychaetes (e.g., Ophelia). prodissoconch II, or shell that is subsequently The commensal nemertean, Malacobdella added to the initial shell zone. Finally, shell grossa, occurs in up to 80% of the clams (Fig. secreted following metamorphosis is simply 1a) (Ricketts and Calvin 1952; Haderlie and referred to as the dissoconch (see Fig. 2, Abbott 1980). These nemerteans are found Brink 2001). Once the larva develops a foot, attached to the clam’s gills with their posterior usually just before metamorphosis and loss of sucker and they feed on planktonic organisms the velum, it is called a pediveliger (see Fig. in the water that is passed over the gill 1, Kabat and O’Foighil 1987; Brink 2001). surface; there is believed to be no harmful (For generalized life cycle see Fig. 1, Brink effect (Ricketts and Calvin 1952; Kozloff 2001.) Swimming larval duration is up to 1991). eight weeks (Ricketts and Calvin 1952; Abundance: Populations can be very Haderlie and Abbott 1980). Larvae of Siliqua abundant in certain locals, but they move and patula are free swimming, but they often stay fluctuate, which may be due to sand close to sediment surface (Haderlie and movement from storms and surf. Densest Abbott 1980). After metamorphosis, groups occur near mean low water individuals are the size of wheat grain or (Anonymous 1968). Up to 10,123 clams/m2 smaller and reach to 1.5 cm by end of the were reported in British Columbia, Canada “growing season” in December (Washington, (see Table 6, Bourne and Quayle). Anonymous 1968). Juvenile: Juveniles have an oval shell outline until they are about 2.5 mm in length

A publication of the University of Oregon Libraries and the Oregon Institute of Marine Biology Individual species: http://hdl.handle.net/1794/12920 and full 3rd edition: http://hdl.handle.net/1794/18839 Email corrections to: [email protected] (Pohlo 1963). Individuals are with central downward trend. In 1976, Oregon total beak, but not elongate (see Fig. 6, Pohlo harvest was 2,211,000 clams (Link 1977). 1963). Eighty-six percent of third year clams Additional predators include seagulls, ducks, (approximately 10 cm in length) are sexually , crab, and fish (e.g. Starry flounder) mature or maturing (Queen Charlotte Island, (Anonymous 1968; Haderlie and Abbott Fraser 1936). In British Columbia, clams 1980). Interestingly, DNA sequence data reached 90 mm by about 1.5–3 years old revealed that razor clam species in the (Bourne and Quayle 1970). commercially harvested genus Ensis are often Longevity: 12 (Washington) to 19 years of mislabeled as congeneric cryptic species with age (Alaska) (Ricketts and Calvin 1952; sympatric distributions (Esperina et al. 2009; Haderlie and Abbott 1980); little growth is Vierna et al. 2013). seen after 15 years (Alaska, Haderlie and Behavior: Siliqua patula is known for its Abbott 1980). The largest individuals in quick, efficient digging (see Burrow). California were nine years old (Haderlie and Individuals move especially rapidly in the Abbott 1980). Mortality is high among young second or "slosh" layer of sand (Anonymous individuals (reaching up to 99%), with 1968). Digging is accomplished by the ability greatest losses after major storms of the anchor-shaped foot to change shape. (Anonymous 1968). Extraordinary muscle capacity and the Growth Rate: Growth can be measured by displacement of body fluids are responsible annual shell rings; growing seasons show as for this (Pohlo 1963; Kozloff 1993). Digging is wide brown areas between rings. Growth vertical, and is sometimes angled toward the proceeds as follows: 20 mm in first year, 130 sea with very little horizontal movement. mm after 5 years, and 160 mm after 13 years Individuals 3 to 8 cms in length bury (Haderlie and Abbott 1980). Individuals reach themselves within 7 and 27 seconds, 11.5 cm in length by approximately 3.5 years respectively (Pohlo 1963). (Washington). Washington and California (e.g., Pismo) individuals grow rapidly, but do Bibliography not reach as large a size or live as long as they do in Alaska (Chignik Bay, Weymouth et 1. ADAMS, N. G., M. LESOING, and V. al. 1926; Ricketts and Calvin 1952). Growth L. TRAINER. 2000. Environmental rates tend to slow after 10 cm sizes are conditions associated with domoic reached (Weymouth and McMillin 1931). acid in razor clams on the Washington Winter shell lengths were measured in Long coast. Journal of Research. Beach, British Columbia, Canada and were 19:1007-1015. 37mm, 91mm, 112.5 mm, 123 mm, and 2. ANONYMOUS. 1968. Invertebrate 131mm in years 1–5, respectively (Bourne fisheries, p. 35-49. Department of Fish and Quayle 1970). and Wildlife, Oregon State University, Food: A of planktonic diatoms. Corvallis, OR. Siliqua patula concentrates phytoplankton 3. BISHOP, J. A. 2000. A record size for and, at the same time, concentrates some the razor clam Siliqua patula. Festivus. species that are associated with harmful algal 32:77-78. blooms (e.g., Pseudo-nitzschia). Toxins 4. BOURNE, N. 1979. Razor clam, (domioc acid) within their tissues can be Siliqua patula Dixon, breeding and dangerous if ingested by humans (Horner et recruitment at Masset, British al. 1997; Dortch et al. 1997; Kumar et al. Columbia. Proceedings of the National 2009; Chadsey et al. 2012). Shellfisheries Association. 69:21-29. Predators: Siliqua patula is probably the 5. BOURNE, N., and D. B. QUAYLE. most highly prized food mollusk in the 1970. Breeding and growth of razor northwest, thus this species has been clams in British Columbia. Technical extensively harvested both recreationally and Report of the Fisheries Research commercially. Unrestricted in 1925, Board of Canada. No. 232:1-42. harvesting severely harmed populations 6. BREESE, W. P., and A. ROBINSON. (Weymouth and McMillin 1931) and lead to a 1981. Razor clams, Silqua patula

Hiebert, T.C. 2015. Siliqua patula. In: Oregon Estuarine Invertebrates: Rudys' Illustrated Guide to Common Species, 3rd ed. T.C. Hiebert, B.A. Butler and A.L. Shanks (eds.). University of Oregon Libraries and Oregon Institute of Marine Biology, Charleston, OR. (Dixon): gonadal development, Journal of Agricultural and Food induced spawning and larval rearing. Chemistry. 57:495-502. Aquaculture. 22:27-33. 16. HADERLIE, E. C., and D. P. ABBOTT. 7. BRINK, L. A. 2001. Mollusca: Bivalvia, 1980. Bivalvia: the clams and allies, p. p. 129-149. In: Identification guide to 355-410. In: Intertidal invertebrates of larval marine invertebrates of the California. R. H. Morris, D. P. Abbott, Pacific Northwest. A. Shanks (ed.). and E. C. Haderlie (eds.). Stanford Oregon State University Press, University Press, California. Corvallis, OR. 17. HEALY, J. M. 1995. Comparative 8. CHADSEY, M., V. L. TRAINER, and T. spermatozoal ultrastructure and its M. LESCHINE. 2012. Cooperation of taxonomic and phylogenetic science and management for harmful significance in the bivalve order algal blooms: domoic acid and the Veneroida. Memoires du Museum Washington coast razor clam fishery. National d'Histoire Naturelle. 166:155- Coastal Management. 40:33-54. 166. 9. COAN, E. V., and P. VALENTICH- 18. HERTLEIN, L. G. 1961. A new species SCOTT. 2007. Bivalvia, p. 807-859. In: of Siliqua (Pelecypoda) from western The Light and Smith manual: intertidal . Bulletin of the invertebrates from central California to Southern California Academy of Oregon. J. T. Carlton (ed.). University Sciences. 60:12-19. of California Press, Berkeley, CA. 19. HIRSCHHORN, G. 1962. Growth and 10. CONNOLLY, T. J. 1995. mortality rates of the razor clam Archaeological evidence for a former (Siliqua patula) on Clatsop Beaches, bay at Seaside, Oregon. Quaternary Oregon. Contributions Oregon Fish Research. 43:362-369. Commission. No. 27:1-55. 11. DIXON, G. 1789. A voyage around the 20. HORNER, R. A., D. L. GARRISON, world. George Goulding, London. and F. G. PLUMLEY. 1997. Harmful 12. DORTCH, Q., R. ROBICHAUX, S. algal blooms and red tide problems on POOL, D. MILSTED, G. MIRE, N. N. the US west coast. Limnology and RABALAIS, T. M. SONIAT, G. A. Oceanography. 42:1076-1088. FRYXELL, R. E. TURNER, and M. L. 21. HORNER, R. A., and J. R. POSTEL. PARSONS. 1997. Abundance and 1993. Toxic diatoms in western vertical flux of Pseudo-nitzschia in the Washington waters (US west coast). northern Gulf of Mexico. Marine Hydrobiologia. 269:197-205. Ecology Progress Series. 146:249- 22. KABAT, A. R., and D. O'FOIGHIL. 264. 1987. Phylum Mollusca, Class 13. DRUM, A. S., T. L. SIEBENS, E. A. Bivalvia, p. 309-353. In: Reproduction CRECELIUS, and R. A. ELSTON. and development of marine 1993. Domoic acid in the Pacific razor invertebrates of the northern Pacific clam, Silqua patula (Dixon, 1789). Coast. M. F. Strathmann (ed.). Journal of Shellfish Research. 12:443- University of Washington Press, 450. Seattle, WA. 14. ELSTON, R. A., and M. G. PEACOCK. 23. KEEN, A. M. 1971. Sea shells of 1984. A Rickettsiales-like infection in tropical west America: marine the , Silqua patula. mollusks from Baja California to Peru. Journal of Invertebrate Pathology. Stanford University Press, Stanford, 44:84-96. CA. 15. ESPINEIRA, M., J. M. VIEITES, and 24. KEEN, A. M., and E. COAN. 1974. F. J. SANTACLARA. 2009. Marine molluscan genera of western Development of a method for the North America: an illustrated key. genetic identification of commercial Stanford University Press, Stanford, bivalve species based on CA. mitochondrial 18S rRNA sequences.

A publication of the University of Oregon Libraries and the Oregon Institute of Marine Biology Individual species: http://hdl.handle.net/1794/12920 and full 3rd edition: http://hdl.handle.net/1794/18839 Email corrections to: [email protected] 25. KOZLOFF, E. N. 1993. Seashore life delimitation and DNA barcoding of of the northern Pacific coast: an Atlantic Ensis (Bivalvia, Pharidae). illustrated guide to northern California, Zoologica Scripta. 43:161-171. Oregon, Washington, and British 35. VON COSEL, R. 1992. Solen Columbia. University of Washington rosaceus: three species. Veliger. Press, Seattle. 35:366-380. 26. KUMAR, K. P., S. P. KUMAR, and G. 36. WEKELL, J. C., E. J. GAUGLITZ, JR., A. NAIR. 2009. Risk assessment of H. J. BARNETT, C. L. HATFIELD, D. the amnesic shellfish poison, domoic SIMONS, and D. AYRES. 1994. acid, on and humans. Journal Occurrence of domoic acid in of Environmental Biology. 30:319-325. Washington State razor clams (Siliqua 27. LASSUY, D. R., and D. SIMONS. patula) during 1991-1993. Natural 1989. Species profiles, life histories Toxins. 2:197-205. and environmental requirements of 37. WEYMOUTH, F. W., and H. C. coastal fish and invertebrates: Pacific MCMILLIN. 1931. The relative growth Northwest. Pacific razor clam. US and mortality of the Pacific razor clam Fish and Wildlife Service Biological (Siliqua patula Dixon), and their Report. 82:I-VI, 1-16. bearing on the commercial Fishery. 28. LECLAIR, L. L., and S. R. PHELPS. Bulletin, Fishery Bulletin. 46:543-567. 1994. Genetic characteristics and 38. WEYMOUTH, F. W., H. C. MCMILLIN, relationships of five razor clam (Silqua and H. B. HOLMES. 1926. Growth and patula, Dixon) populations along the age at maturity of the Pacific razor Pacific coast of North America. clam, Siliqua patula (Dixon). Fishery Journal of Shellfish Research. 13:207- Bulletin. 41:201-236. 216. 39. WEYMOUTH, F. W., H. C. MCMILLIN, 29. MCLACHLAN, A., J. E. DUGAN, O. and W. A. RICH. 1931. Latitude and DEFEO, A. D. ANSELL, D. M. relative growth in the razor clam HUBBARD, E. JARAMILLO, and P. E. Siliqua patula. Journal of Experimental PENCHASZADEH. 1996. Beach clam Biology. 8:228-249. fisheries. Oceanography and Marine Biology. 34:163-232. 30. OLDROYD, I. S. 1924. Marine shells of and vicinity. University of Washington Press, Seattle. 31. POHLO, R. H. 1963. Morphology and mode of burrowing in Siliqua patula and Solen rosaceus (Mollusca: Bivalvia). Veliger. 6:98-104. 32. RICKETTS, E. F., and J. CALVIN. 1952. Between Pacific tides : an account of the habits and habitats of some five hundred of the common, conspicuous seashore invertebrates of the Pacific Coast between Sitka, Alaska, and Northern Mexico. Stanford : Stanford University Press, Stanford. 33. TAYLOR, C. C. 1959. Temperature and growth: the Pacific razor clam. Journal du Conseil. 25:93-101. 34. VIERNA, J., J. CUPERUS, A. MARTINEZ-LAGE, J. M. JANSEN, A. PERINA, H. VAN PELT, and A. M. GONZALEZ-TIZON. 2014. Species

Hiebert, T.C. 2015. Siliqua patula. In: Oregon Estuarine Invertebrates: Rudys' Illustrated Guide to Common Species, 3rd ed. T.C. Hiebert, B.A. Butler and A.L. Shanks (eds.). University of Oregon Libraries and Oregon Institute of Marine Biology, Charleston, OR.