Leukoma Staminea Phylum: Mollusca Class: Bivalva; Heterodonta Order: Veneroida Rock Cockle, Littleneck Clam, Hardshell Clam Or Pacific Littleneck Family: Veneridae

Leukoma staminea Phylum: Mollusca Class: Bivalva; Heterodonta Order: Veneroida Rock cockle, littleneck clam, hardshell clam or Pacific littleneck Family: Veneridae

Taxonomy: Confusion surrounds the Color: appropriate genus for this species. Many Interior: The ligament is external and species were designated as Protothaca (or seated on a nymph. The mantle edge is subspecies thereof, e.g., Protothaca composed of four tentacular folds, the fourth (Protothaca) staminea, Kabat and O’Foighil of which is large, glandular and comprised of 1987; Lazo 2004), based on shell sculpture, mucocytes. There is also a large dorsal ridge, and are likely the same species. Many which contains mucopolysaccharides and researchers have thus adopted the older protein-secreting cells (Hillman and Bennett designated name, Leukoma (e.g., Groesbeck 1979). et al. 2014) for the species described below Exterior: (see (Coan and Valentich-Scott 2007). Byssus: However, some local guides (e.g., Brink 2001) Gills: and several publications also use Protothaca Shell: The shell is very heavy, L. staminea is staminea. Other synonyms include sometimes called the rock cockle because of Vererupsis staminea, Protothaca its strong radiating ridges (Ricketts and Calvin restoriationensis, Paphia staminea and 1952). variations var. ruderata, var. orbella Interior: Shell interior is porcelaneous (Deshayes; Carpenter). and the ventral margin is with fine crenulate sculpture (Fig. 2). The muscle scars are Description almost equal and the pallial line is broken by Size: Individuals 2–75 mm in length; average a deep pallial sinus (Fig. 2). The file-like length is 25–50 mm (Ricketts and Calvin structure of the inside ventral margin is a 1952; Kozloff 1993). Maximum length of distinct feature of this species (Kozloff 1993). 30.70 mm was reported for specimens Exterior: The shell shape is sub-oval collected in Prince William Sound, Alaska and heavy. There are numerous, fine, (Nickerson 1977). radiating ribs as well as concentric ridges. Color: Overall color is variable. Young The radial ribs are more conspicuous for specimens often with brown markings like a individuals that nestle within rocks, i.e., those brown checkerboard pattern on their shell found in pholad borings (Coan and Carlton (squares on each valve) (Kozloff 1993). 1975). Specimens often have differing shell Adults can be uniform brown, pinkish, or shapes based on their different habitats orange, with a white interior (Kozloff 1993) (Fraser and Smith 1928). General Morphology: Bivalve mollusks are Hinge: There are three compressed bilaterally symmetrical with two lateral valves cardinal teeth in the hinge area and no lateral or shells that are hinged dorsally and teeth. The hinge plate is wide and set at an surround a mantle, head, foot and viscera angle (Fig. 2). (see Plate 393B, Coan and Valentich-Scott Eyes: 2007). The Veneroida is a large and diverse Foot: bivalve heterodont order that is characterized Siphons: The siphons are short and fused by well developed hinge teeth. There are 22 (Kozloff 1993). local families, and members of the Veneridae Burrow: Leukoma staminea is a poor digger, have three cardinal teeth on each valve (see and thus does not live in sediments that Plate 396H, Coan and Valentich-Scott 2007) require frequent digging (e.g., those that shift) (Fig. 2). (Ricketts and Calvin 1952); prefers clay Body: (see Fig. 299, Kozloff 1993). (Ricketts and Calvin 1952). Burrows are less

A publication of the University of Oregon Libraries and the Oregon Institute of Marine Biology Individual species: http://hdl.handle.net/1794/12918 and full 3rd edition: http://hdl.handle.net/1794/18839 Email corrections to: [email protected] than 20 cm deep (Ricketts and Calvin 1952). lamellifera, but they possess anterior lateral Not always buried at all (Dunham et al. 2006). teeth and valves that are separated by a Can move and reburrow using their foot narrow gape, posteriorly. Saxidomus nuttalli (Shaw 1986). Semi-infaunal to 10 cm in and S. giganteus can be differentiated as the coarse sediment; burrowing rate depends on former species has a elongate and thinner the sediment size, with faster burrowing in shell as well as a narrow escutcheon (not finer sediment (Alexander et al. 1993). present in S. giganteus). The shell sculpturing in S. giganteus also appears Possible Misidentifications smooth as the commarginal ribs are thin, low Veneroida is a large bivalve order, and tightly spaced, while the opposite is true characterized by well-developed hinge teeth, for S. nuttalli. including most heterodonts. The family The venerid species without Veneridae is characterized by a hinge without predominately commarginal ribs include lateral teeth, ligament that is entirely external, Ruditapes philippinarum (Adams & Reeve, radial ribs on shell exterior, and three cardinal 1850) (called Venerupis philippinarum in the teeth on each shell valve. There are 12–16 most recent Light and Smith manual) and species reported locally in this family within members of the genus Leukoma. Leukoma the genera Nutricola, Saxidomus, and species differ from R. philippinarum by having Leukoma, with two species in each, and an inner ventral margin that is not smooth Gemma gemma), Irusella lamellifera), Tivela (i.e., inner margin crenulated), a ligament that stultorum, Venerupis philippinarum, is not prominent and fused siphons. Mercenaria mercenaria, Callithaca tenerrima, Leukoma staminea has shell sculpturing that each with a single species represented is dominated by numerous radiating ribs, with locally. faint commarginal ridges and the opposite is Nutricola species are small, with shells true for its congener (i.e., dominant radiating usually less than 10 mm in length. Gemma and commarginal ridges). gemma also has a small shell, but it is A closely related Venerid, R. triangular in shape compared to Nutricola philippinarum (Fig. 1a), has been introduced species with elongate or oval shells. Tivela from Japan, and is common in mud of bays stultorum also has a triangular shell, but (Coan and Carlton 1975). It is elongate, oval, individuals are larger than G. gemma and and has a prominently elevated ligament. Its have a smooth shell surface with shiny radial ribs are quite strong and its color periostracum. Nutricola tantilla has a shell pattern distinctive. Its internal ventral margin that is white in color and siphons that are is smooth, not crenulate, and its pallial sinus fused (or nearly so) at the tips. Nutricola only moderately deep. Its internal color is confusa has a shell that is purple in color, yellowish with a purple stain. It lives at siphons that bear a conspicuous cleft as well slightly higher elevations than does L. as conspicuous anterior lateral teeth, which staminea and can grow to 50 mm in length are weak in N. tantilla. (Washington, Haderlie 1980). Other bay The remaining species have shells clams of the same size and habitat as L. larger than 10 mm in length. Some species staminea lack both its radial and concentric have shell sculpturing that is dominated by sculpture. commarginal ribs with fine radial ridges and others have shells that have radial ridges with Ecolgical Information inconspicuous, or not predominating, Range: Type locality is California (see Orr et commarginal ribs. Of those in the former al. 2013). Known range extends from the category, I. lamellifera has widely spaced Aleutian Islands in Alaska to the Socorro commarginal lamellae and a shell that is short Islands, Mexico. Previously known varieties compared to M. mercenaria and C. tenerrima. of this species were divided into those north The two latter species have elongated shells, of San Francisco: var. ruderata (on beaches) no anterior lateral teeth and valves that do not and var. orbella (in pholad borings). Northern gape. Saxidomus species also have an limit is Prince William Sound, Alaska (Feder et elongate shell, when compared to I. al. 1979).

Hiebert, T.C. 2015. Leukoma staminea. 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. Local Distribution: Leukoma staminea is a staminea in Puget Sound, Washington common clam in most of the larger Northwest showed genetic heterogeneity reflecting and estuaries and bays, and around rocky ocean potentially caused by the hydrology of the outcroppings. Puget Sound (Parker et al. 2003). Habitat: Occurs in coarse sand as well as Salinity: Collected at salinities of 30. fine gravel with mud, stones, or shell (Kozloff Temperature: 1974); seldom found in fine, pure sand Tidal Level: Intertidal and subtidal (Hancock (Fraser and Smith 1928). As it is a poor et al. 1979); upper 20 cm of cobble, sand and digger, L. staminea does not do well in mud (Kabat and O’Foighil 1987). Occurs from shifting sand, but prefers packed mud, clayey below half tide to lowest tideline (Puget gravel (Ricketts and Calvin 1971). Individuals Sound, Washington, Kozloff 1974). A range usually found 3–8 cm below surface, or of +1.52 to -0.76 m was reported for nestling into sand, rocks, and empty pholad individuals in Prince William Sound, Alaska holes (Coan and Valentich-Scott 2007). Both (Nickerson 1977). L. staminea and Mytilus edulis co-occur in Associates: Often found with the cockle, Auke Bay, Alaska where their survival is Clinocardium nuttallii, and particularly with the negatively effected by burial depth (as little as butter clam, Saxidomus giganteus (Nickerson 6 cm) and duration by bark chips from a log 1977). Often bored by drilling gastropods transferring facility (Freese and O’Clair 1987). (Haderlie 1980). The majority (~70%) of L. A bioindicator species (e.g., Swartz et al. staminea individuals collected from Cooper’s 1979; copper and copper-binding proteins Cove, British Columbia were infested with Roesijadi 1980), Leukoma staminea survival cysts from an apicomplexan parasite that and growth was also negatively effected by oil were 20–150 µm in diameter (Desser and from the Exxon Valdez oil spill at least 5–6 Bower 1997). Leukoma staminea and S. years following the spill (Fukuyama et al. giganteus co-occur on Kiket Island, 2000; Fukuyama et al. 2014). Aside from the Washington, where the greatest diversity and negative effect of hydrocarbon accumulation richness of other marine invertebrates are within clam tissues (see Thomas et al. 2007), found (Houghton 1977). Co-occurs with other Fukuyama et al. (2014) suggest that the clams (e.g., Tresus capax and T. nuttallii, removal of fine sediment associated with oil Gillispie and Bourne 2004; Sanguinolaria spill cleanup had a negative impact on L. nuttallii, Peterson and Andre 1980), but the staminea populations. However, when tested presence of these species does not seem to for the accumulation of hydrocarbons from effect L. staminea abundance (Peterson and crude oil, L. staminea (a suspension feeder) Andre 1980). It has been suggested that the showed less uptake than deposit feeders non-indigenous manila clam, Venerupis (e.g., Macoma inquinata and Phascolosoma philippinarum is outcompeting and replacing agassizii, Roesijadi et al. 1978). Interestingly, L. staminea in some habitats (British L. staminea individuals were also more likely Columbia, Canada, Bendell 2014). to be preyed upon by Cancer magister in Abundance: Leukoma staminea is common; oiled habitats (Pearson et al. 1981). “Clam the most abundant clam of the lower intertidal gardens”, created adjacent to intertidal rock in Puget Sound, Washington (Kozloff 1974). walls constructed by human populations in In a Coos Bay estimate (of the genus the Holocene, have four times as many S. Protothaca) from 1975, Hancock et al., giganteus and twice as many L. staminea estimated there were 843,000 clams individuals as non-walled beaches, and weighting 32.6 metric tons (Hancock et al. transplanted juveniles of the latter species 1979). Also common in Tillamook Bay, but also grow faster (1.7 times faster) in clam the density of individuals is light in Alsea, gardens (Groesbeck et al. 2014). Individuals Siuslaw, and Netarts estuaries (Hancock et al. may be both infaunal when found in mud and 1979). Can be very abundant with several muddy sand or epifaunal among gravel, the individuals in one shovel full, and can even be latter habitat yielding the most damaged raked from just under the sediment surface shells (Lazo 2004). Unlike the co-occurring (Kozloff 1993). Individuals sometimes even bivalve, Macoma balthica, populations of L. on top of one another: “2 to 3 shovels full will

A publication of the University of Oregon Libraries and the Oregon Institute of Marine Biology Individual species: http://hdl.handle.net/1794/12918 and full 3rd edition: http://hdl.handle.net/1794/18839 Email corrections to: [email protected] yield enough clams to feed several hungry prodissoconch I and is followed by a people” (Ricketts and Calvin 1952). In British prodissoconch II, or shell that is subsequently Columbia beaches, assessed in 1993, L. added to the initial shell zone (see Fig. 1, staminea density was ranged from 0 to 180 Caddy 1969). Finally, shell secreted following individuals/m2 (Gillispie and Bourne 2004). In metamorphosis is simply referred to as the 2006, low densities were reported dissoconch (see Fig. 2, Brink 2001). Once (presumably due to over harvest) in British the larva develops a foot, usually just before Columbia, Canada (up to 7 individuals/m2, metamorphosis and loss of the velum, it is Dunham et al. 2006). Estimates of the total called a pediveliger (see Fig. 1, Caddy 1969; population of L. staminea at Chugachik Kabat and O’Foighil 1987; Brink 2001). (For Island, Alaska were determined for 1992, generalized life cycle see Fig. 1, Brink 2001). 1995, and 1996 as 7.2, 3.3, and 5.5 million Free-swimming (Brink 2001) veliger larvae of clams, respectively. Of this total, 136,000, L. staminea are found in the plankton after 65,000, and 115,000 kg were harvested spawning from April to September through commercially (Bechtol and Gustafson 1998). October (Strait of Georgia, Quayle 1943 in Kabat and O’Foighil 1987) and February in Life-History Information Vancouver, British Columbia (Kabat and Reproduction: Dioecious (separate sexes), O’Foighil 1987), and from April through but some hermaphrodism occurs (Fraser and October (Broughton Archipelago, British Smith 1928; Kabat and O’Foighil 1987). Columbia, Dunham et al. 2006). Ideal Spawning in Oregon occurs from April conditions for rearing larvae are 10–15˚C at through August (Robinson and Breese 1982) salinities of 32. Larvae can survive at slightly and in February–March (Puget Sound, higher temperatures (e.g., 20˚C) at the same Washington and Sydney, British Columbia, salinity but higher temperatures and low Canada, Ricketts and Calvin 1952). salinity (e.g., 27) are lethal (Phibbs 1971). Spawning has also been reported from April Trochophore larvae are 60–80 µm at 12 to September for the Strait of Georgia hours, straight-hinge veligers at 24 hours. (Quayle 1943 in Kabat and O’Foighil 1987; Larvae have a ciliated velum and are 150 µm Shaw 1986) and in January in Vancouver BC in length after 1 week, and an umbo when (Fraser 1929). Quayle (1943) reported that they are 260–280 µm in length at roughly 2 females may spawn several times during a weeks. The total pelagic duration of L. season, while males release all gametes at staminea is 3 to 4 wks (Shaw 1986). At once; while Feder et al. (1979) found females metamorphosis, larvae are 260–280 µm in spawn from June–September and males from length (Gillespie and Kronlund 199). June–January in Prince William Sound, Juvenile: Gonads are apparent when Alaska. Spawning in response to algal juveniles are 1 mm in length, but sexes blooms has been reported for this species as cannot be differentiated until they are 15–30 well as Saxidomus giganteus (Robinson and mm in length, a size reached by 2–3 years Breese 1982). Gametes discharged through (Shaw 1986; Kabat and O’Foighil 1987). the siphon during spawning (Shaw 1986). Individuals begin spawning after two years. Larva: Bivalve development generally Longevity: A few individuals over seven proceeds from external fertilization via years old were observed by Schmidt and broadcast spawning through a ciliated Warme (1969). Mortality is greatest before trochophore stage to a veliger larva. Bivalve sexual maturity (60%) and in old age (Schmidt veligers are characterized by a ciliated velum and Warme 1969). Few clams are older than that is used for swimming, feeding and ten years (Fraser and Smith 1928), with a respiration. The veliger larva is also found in maximum age up to 13 (Shaw 1986) or 15 many gastropod larvae, but the larvae in the years (Nickerson 1977). two groups can be recognized by shell Growth Rate: Growth rate and age are morphology (i.e. snail-like versus clam-like). determined by examination of rings caused by In bivalves, the initial shelled-larva is called a reduced growth in winter or different growth D-stage or straight-hinge veliger due to the rates in different localities (but see Berta “D” shaped shell. This initial shell is called a 1976). Growth is often slow in early years on

Hiebert, T.C. 2015. Leukoma staminea. 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. exposed beaches, due to movement, storms, ka, Takesue and Geen 2004). A etc. and becomes more rapid in later years commercially harvested species, and (the opposite may be true for individuals in populations were dramatically depleted in protected sites). By the end of second year, 1931 (Ricketts and Calvin 1952; Shaw 1986). specimens are 25 mm in length, and the third A harvest as high as over 100,000 kg was year, they are 35 mm (Fraser and Smith reported in 1975 (Broughton Archipelago, 1928). Clams were 47–54, 40–45 mm in British Columbia, Canada, Dunham et al. length were estimated to be 6–8 and 3–7 2006). (see Bechtol and Gustafson 1998 for years old at three sites in the Broughton commercial summary). After this peak in Archipelago, British Columbia, Canada, 1975, landings decreased dramatically. respectively (Dunham et al. 2006). At three Behavior: A poor digger, L. staminea does British Columbia beaches measured in 1993, not burrow vertically; the siphons and foot are individuals 25–50 mm in length were 3–7 short. Thus individuals remain close to years old, 30–64 mm were 3–9 years, and surface of substrate and burrows easily 29–46 were 3–8 years old; with individuals horizontally (personal communication H. Van reaching 38 mm in length at four years of age Veldhuizen). (Gillispie and Bourne 2004). Legal catch size is 38 mm in length, which occurs when Bibliography individuals are approximately 4–5 years old (Bechtol and Gustafson 1998; Gillispie and 1. ALEXANDER, R. R., R. J. STANTON, Bourne 2004). Growth rate decreases as and J. R. DODD. 1993. Influence of intraspecific density increases (Peterson sediment grain-size on the burrowing 1982). A length of 30 mm was achieved in 8 of bivalves: correlation with distribution years (see also Fig. 4, Shaw 1986). and stratigraphic persistence of Food: A suspension feeder, with short selected neogene clams. Palaios. siphons that necessitate feeding close to 8:289-303. sediment surface. The ingestion and 2. BECHTOL, W. R., and R. L. concentration of toxic algae (e.g., from the GUSTAFSON. 1998. Abundance, genera Alexandrium, Gymnodinium, recruitment, and mortality of Pacific Pyrodinium, Smolowitz and Doucette 1995) littleneck clams Protothaca staminea leads to paralytic shellfish poisoning, at Chugachik Island, Alaska. Journal rendering the clams dangerous for human of Shellfish Research. 17:1003-1008. consumption (Ricketts and Calvin 1952). 3. BENDELL, L. I. 2014. Evidence for Predators: Adults are often preyed upon by declines in the native Leukoma birds (e.g., diving ducks, Fukuyama et al. staminea as a result of the intentional 2000), terrestrial animals (Fukuyama et al. introduction of the non-native 2000), and drilling gastropods (e.g., Polinices Venerupis philippinarum in coastal lewisii, Peitso et al. 1993; Grey et al. 2007), British Columbia, Canada. Estuaries sea stars, fish (siphon nipping, Peterson and and Coasts. 37:369-380. Quammen 1982), and see otters (Feder et al. 4. BERTA, A. 1976. An investigation of 1979). Crabs, Cancer productus, forage for individual growth and possible age clams in areas where they are most dense relationships in a population of (Boulding and Hay 1984; Boulding and Protothaca staminea (Mollusca: Labarbera 1986), the European green crab, Pelecypoda). Paleobios. 21:1-26. Carcinus maenas (Curtis et al. 2012), Cancer 5. BOULDING, E. G., and T. K. HAY. magister (Pearson et al. 1981; Juanes and 1984. Crab response to prey density Hartwick 1990), and Cancer anthonyi can result in density-dependent (Peterson 1983). Leukoma staminea is also mortality of clams. Canadian Journal an intermediate host to the “sporocysts of a of Fisheries and Aquatic Sciences. Coccidia-like Apicomplexa” (see Associates, 41:521-525. Desser and Bower 1997). Larvae are prey to 6. BOULDING, E. G., and M. planktonic predators and other suspension LABARBERA. 1986. Fatigue damage: feeders. Common in coastal middens (~3-9 repeated loading enables crabs to

A publication of the University of Oregon Libraries and the Oregon Institute of Marine Biology Individual species: http://hdl.handle.net/1794/12918 and full 3rd edition: http://hdl.handle.net/1794/18839 Email corrections to: [email protected] open larger bivalves. Biological 14. FREESE, J. L., and C. E. OCLAIR. Bulletin. 171:538-547. 1987. Reduced survival and condition 7. BRINK, L. A. 2001. Mollusca: Bivalvia, of the bivalves Protothaca staminea p. 129-149. In: Identification guide to and Mytilus edulis buried by larval marine invertebrates of the decomposig bark. Marine Pacific Northwest. A. Shanks (ed.). Environmental Research. 23:49-64. Oregon State University Press, 15. FUKUYAMA, A. K., G. SHIGENAKA, Corvallis, OR. and D. A. COATS. 2014. Status of 8. COAN, E. V., and P. VALENTICH- intertidal infaunal communities SCOTT. 2007. Bivalvia, p. 807-859. In: following the Exxon Valdez oil spill in The Light and Smith manual: intertidal Prince William Sound, Alaska. Marine invertebrates from central California to Pollution Bulletin. 84:56-69. Oregon. J. T. Carlton (ed.). University 16. FUKUYAMA, A. K., G. SHIGENAKA, of California Press, Berkeley, CA. and R. Z. HOFF. 2000. Effects of 9. CURTIS, D. L., L. SAUCHYN, L. residual Exxon Valdez oil on intertidal KEDDY, T. W. THERRIAULT, and C. Protothaca staminea: mortality, M. PEARCE. 2012. Prey preferences growth, and bioaccumulation of and relative predation rates of adult hydrocarbons in transplanted clams. European green crabs (Carcinus Marine Pollution Bulletin. 40:1042- maenas) on various bivalve species in 1050. British Columbia, Canada. Canadian 17. GILLESPIE, G. E., and N. F. Technical Report of Fisheries and BOURNE. 2005. Exploratory intertidal Aquatic Sciences. 3014:1-14,III. bivalve surveys in British Columbia - 10. DESSER, S. S., and S. M. BOWER. 2004. Canadian Manuscript Report of 1997. The distribution, prevalence, Fisheries and Aquatic Sciences. and morphological features of the 2734:1-144,VIII. cystic stage of an apicomplexan 18. GREY, M., P. G. LELIEVRE, and E. G. parasite of native littleneck clams BOULDING. 2007. Selection for prey (Protothaca staminea) in British shell thickness by the naticid Columbia. Journal of Parasitology. gastropod Euspira lewisii (Naticidae) 83:642-646. on the bivalve Protothaca staminea 11. DUNHAM, J. S., B. KOKE, G. E. (Veneridae). Veliger. 48:317-322. GILLESPIE, and G. MEYER. 2007. An 19. GROESBECK, A. S., K. ROWELL, D. exploratory survey for littleneck clams L., and A. K. SALOMON. 2014. (Protothaca staminea) in the Ancient clam gardens increased Broughton Archipelago, British shellfish production: adaptive Columbia - 2006. Canadian strategies from the past can inform Manuscript Report of Fisheries and food security today. Plos One. 9. Aquatic Sciences. 2787:1-33. 20. HADERLIE, E. C., and D. P. ABBOTT. 12. FEDER, H. M., J. C. HENDEE, P. 1980. Bivalvia: the clams and allies, p. HOLMES, G. J. MUELLER, and A. J. 355-410. In: Intertidal invertebrates of PAUL. 1979. Examination of California. R. H. Morris, D. P. Abbott, reproductive cycle of Protothaca and E. C. Haderlie (eds.). Stanford staminea using histology, wet University Press, California. weight/dry weight ratios, and condition 21. HANCOCK, D. R., T. F. GAUMER, G. indexes. Veliger. 22:182-187. B. WILLEKE, G. P. ROBART, and J. 13. FRASER, C. M., and G. M. SMITH. FLYNN. 1979. Subtidal clam 1928. Notes on the ecology of the little populations: distribution, abundance, neck clam, Paphia staminea Conrad. and ecology. Oregon State University, Transactions of the Royal Society of Sea Grant College Program, Corvallis. Canada, Section V, Biological 22. HILLMAN, R. E., and H. E. BENNETT. Sciences, Third Series Part 1. 1979. The fourth fold and secretory XXII:249-269. ridge of the mantle edge of the

Hiebert, T.C. 2015. Leukoma staminea. 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. littleneck clam, Protothaca staminea. the Alaska Fisheries Science Proceedings National Shellfisheries Center Bottom-Trawl Survey Association. 69:195-195. Database. NPRB Project 1016 Final 23. HOUGHTON, J. P. 1977. Age and Report. North Pacific Research Board, growth of Protothaca staminea and Alaska. Saxidomus giganteur at Kiket Island 31. PARKER, M. S., P. A. JUMARS, and Washington, USA. Proceedings L. L. LECLAIR. 2003. Population National Shellfisheries Association. genetics of two bivalve species 67:119-119. (Protothaca staminea and Macoma 24. JUANES, F., and E. B. HARTWICK. balthica) in Puget Sound, Washington. 1990. Prey size selection in Journal of Shellfish Research. 22:681- Dungeness Crabs: the effect of claw 688. damage. Ecology. 71:744-758. 32. PEARSON, W. H., D. L. WOODRUFF, 25. KABAT, A. R., and D. O'FOIGHIL. P. C. SUGARMAN, and B. L. OLLA. 1987. Phylum Mollusca, Class 1981. Effects of oiled sediment on Bivalvia, p. 309-353. In: Reproduction predation on the littleneck clam, and development of marine Protothaca staminea, by the invertebrates of the northern Pacific Dungeness Cra, Cancer magister. Coast. M. F. Strathmann (ed.). Estuarine Coastal and Shelf Science. University of Washington Press, 13:445-454. Seattle, WA. 33. PEITSO, E., E. HUI, B. HARTWICK, 26. KOZLOFF, E. N. 1974. Keys to the and N. BOURNE. 1994. Predation by marine invertebrates of Puget Sound, the naticid gastropod Polinices lewisii the San Juan Archipelago, and (Gould) on littleneck clams, Protothaca adjacent regions. University of staminea (Conrad) in British Columbia. Washington Press, Seattle. Canadian Journal of Zoology. 72:319- 27. —. 1993. Seashore life of the northern 325. Pacific coast: an illustrated guide to 34. PETERSON, C. H. 1982. The northern California, Oregon, importance of predation and Washington, and British Columbia. intraspecific and interspecific University of Washington Press, competition in the population biology Seattle. of two infaunal suspension-feeding 28. LAZO, D. G. 2004. Bivalve bivalves, Protothaca staminea and taphonomy: testing the effect of life Chione undatella. Ecological habits on the shell condition of the Monographs. 52:437-475. littleneck clam Protothaca staminea 35. —. 1983. Interactions between two (Mollusca : Bivalvia). Palaios. 19:451- infaunal bivalves, Chione undatella 459. (Sowerby) and Protothaca staminea 29. NICKERSON, R. B. 1977. A study of (Conrad), and two potential enemies, the littleneck clam Protothaca Crepidula onyx and Cancer anthonyi staminea and the butter clam (Rathbun). Journal of Experimental Saxidomus giganteus in a habitat Marine Biology and Ecology. 68:145- permitting coexistence, Prince William 158. Sound, Alaska USA. Proceedings 36. PETERSON, C. H., and S. V. ANDRE. National Shellfisheries Association. 1980. An experimental analysis of 67:85-102. interspecific competition among 30. ORR, J. W., D. T. DRUMM, R. VAN marine filter feeders in a soft-sediment SYOC, K. P. MASLENIKOV, T. W. environment. Ecology. 61:129-139. PIETSCH, D. E. STEVENSON, and R. 37. PETERSON, C. H., and M. L. R. LAUTH. 2013. An annotated QUAMMEN. 1982. Siphon nipping: its checklist of bottom-trawled importance to small fishes and its macroinvertebrates of Alaska, impact on growth of the bivalve with an evaluation of identifications in Protothaca staminea (Conrad).