"Littleneck clam" redirects here. For the Atlantic littleneck or small quahogs, see hard clam.
Leukoma staminea, commonly known as the Pacific littleneck clam, the littleneck clam, the rock cockle, the hardshell clam, the Tomales Bay cockle, the rock clam or the ribbed carpet shell,[2] is a species of bivalvemollusc in the familyVeneridae.[3] This species of mollusc was exploited by early humans in North America; for example, the Chumash peoples of Central California harvested these clams in Morro Bay approximately 1,000 years ago,[4] and the distinctive shells form middens near their settlements.[5]
Like other members of Veneridae, this species has a chalky shell, the umbo being anterior to the midline of the shell, but closer to the midline than to the anterior end of the shell. The two equal-sized valves are oval or heart-shaped. The width of the shell is greater than a quarter of its length, and the shell seldom exceeds 6 cm (2.4 in) in length. The umbones point towards the anterior end of the shell. The hinge has three cardinal teeth in each valve, and a row of small teeth along the ventral margins of the valves. There are numerous concentric ridges, more clearly demarcked at the anterior end, but the radial ridges are often more clearly sculpted. The foot is large and there is a clearcut pallial sinus.[2]
Right and left valve of the same specimen:
Right valve
Left valve
Distribution and habitatedit
Leukoma staminea is native to the eastern Pacific Ocean. Its range extends along the coasts of North America from the Aleutian Islands and Alaska in the north to Baja California in the south. It usually occurs in protected areas on sand, hard mud and clayey-gravel substrates from the mid and lower shore down to depths of about 10 m (33 ft), usually buried less than 8 cm (3 in) beneath the surface of the sediment. Occasionally it is in more exposed locations, in gravel-filled cracks in rocks or in empty burrows of other clams.[2]
Ecologyedit
This clam is a filter feeder and consumes microscopic algae such as dinoflagellates, diatoms, and cyanobacteria.[2][6] Some dinoflagellates produce neurotoxins, such as saxitoxin and its derivates, that bioaccumulate in the clams and other bivalve mollusks and can cause paralytic shellfish poisoning (PSP) when the clams are eaten.[2][6] Despite this fact, the clam was eaten by Native Americans and is still used as a food for humans.[2] According to a 1996 report from the Marine Advisory Program at the University of Alaska, the United States Food and Drug Administration (FDA) considers seafood unsafe if it contains more than 80 μg of PSP-causing toxins per 100 g of tissue of the seafood.[7][8] PSP is caused by a mixture of at least 21 different chemical species, some of which undergo chemical transformations within the dinoflagellates or within the animals that acquire the saxitoxins, and which are retained by different animals for different lengths of time.[7] It is clear that PSP-causing toxin levels are typically much higher in the summer months[9] though this does not mean the seafood is necessarily safe at other times.[10] Risks also vary based on species[7][8] but seafood available for retail sale is required to meet the FDA standards.[10]
In PSP poisonings that occurred in the summer of 1993 in Kodiak, Alaska, saxitoxin levels as high as 19,600 μg / 100 g were measured in the Alaska blue mussel Mytilus edulis – sufficient to provide a lethal dose in a single 2.5 g mussel.[7] By contrast, the highest measured level of saxitoxin in the Pacific littleneck clam was 580 μg / 100 g according to this 1996 report.[8] Littleneck clams are "typically less toxic and retain their toxins for a shorter amount of time than the other species" such as "butter clams and blue mussels [that] tend to accumulate the highest levels of PSP toxins ... [and] geoducks and scallops [that] tend to be toxic for longer periods of time" but this does not mean that these clams "are always safe to eat [as] you can get PSP from littleneck clams."[11] The reason for the difference is likely that the littleneck clam has an enzyme that converts saxitoxin into decarbamoylsaxitoxin, a capability not shared by the blue mussel nor by the butter clam Saxidomus gigantea (in which levels of saxitoxin as high as 7,750 μg / 100 g have been reported[8]).[12] This transformation to decarbomyl derivative has been reported in some other clam species and significantly reduces the toxicity of saxitoxins present.[13]
^ abHuber, Markus (2018). Bieler R, Bouchet P, Gofas S, Marshall B, Rosenberg G, La Perna R, Neubauer TA, Sartori AF, Schneider S, Vos C, ter Poorten JJ, Taylor J, Dijkstra H, Finn J, Bank R, Neubert E, Moretzsohn F, Faber M, Houart R, Picton B, Garcia-Alvarez O (eds.). "Leukoma staminea (Conrad, 1837)". MolluscaBase. World Register of Marine Species. Retrieved 29 December 2018.
^ abcdefghCowles, Dave (2007). "Leukoma staminea (Conrad, 1857)". Invertebrates of the Salish Sea. Rosario Beach Marine Laboratory (a campus of Walla Walla University, Washington). Retrieved 29 December 2018.
^"Family: Veneridae (Venus Clams)". Gladys Archerd Shell Collection. Washington State University Tri-Cities Natural History Museum. Retrieved 29 December 2018.
^Burnham, C. Michael (2008). "Los Osos Back Bay". The Megalithic Portal. Retrieved 29 December 2018.
^Lightfoot, Kent; Parrish, Otis (2009). California Indians and Their Environment: An Introduction. University of California Press. p. 271. ISBN978-0-520-94228-8.
^ abClark, R. F.; Williams, S. R.; Nordt, S. P.; Manoguerra, A. S. (1999). (PDF). Undersea & Hyperbaric Medicine. 26 (3): 175–184. PMID 10485519. Archived from the original on June 17, 2012.{{cite journal}}: CS1 maint: unfit URL (link)
^ abcdRaLonde, Raymond (October 1996). "Paralytic Shellfish Poisoning: The Alaska Problem" (PDF). Alaska's Maritime Resources. Marine Advisory Board, the University of Alaska. pp. 1–7.
^ abcd"How Toxic Are Alaska's Most Common Shellfish?" (PDF). Alaska's Maritime Resources. Marine Advisory Board, the University of Alaska. October 1996. pp. 10–11.
^Gessner, Brad (October 1996). "Epidemiology of Paralytic Shellfish Poisoning Outbreaks in Alaska" (PDF). Alaska's Maritime Resources. Marine Advisory Board, the University of Alaska. pp. 16–17, 19.
^ ab"Truths and Myths about PSP" (PDF). Alaska's Maritime Resources. Marine Advisory Board, the University of Alaska. October 1996. pp. 14–15.
^Alaska Sea Grant Program (13 August 2015). "Paralytic Shellfish Poisoning in Alaska Facts and Discussion". College of Fisheries and Ocean Sciences at the University of Alaska Fairbanks. Retrieved 22 January 2019.
^Sullivan, John J.; Iwaoka, Wayne T.; Liston, John (1983). "Enzymatic transformation of PSP toxins in the littleneck clam (Protothaca staminea)". Biochemical and Biophysical Research Communications. 114 (2): 465–472. doi:10.1016/0006-291X(83)90803-3. PMID 6882435.
^Deeds, Jonathan R.; Landsberg, Jan H.; Etheridge, Stacey M.; Pitcher, Grant C.; Longan, Sara Watt (2008). "Non-Traditional Vectors for Paralytic Shellfish Poisoning". Marine Drugs. 6 (2): 308–348. doi:10.3390/md6020308. PMC2525492. PMID 18728730.
May 12, 2024
leukoma, staminea, littleneck, clam, redirects, here, atlantic, littleneck, small, quahogs, hard, clam, commonly, known, pacific, littleneck, clam, littleneck, clam, rock, cockle, hardshell, clam, tomales, cockle, rock, clam, ribbed, carpet, shell, species, bi. Littleneck clam redirects here For the Atlantic littleneck or small quahogs see hard clam Leukoma staminea commonly known as the Pacific littleneck clam the littleneck clam the rock cockle the hardshell clam the Tomales Bay cockle the rock clam or the ribbed carpet shell 2 is a species of bivalve mollusc in the family Veneridae 3 This species of mollusc was exploited by early humans in North America for example the Chumash peoples of Central California harvested these clams in Morro Bay approximately 1 000 years ago 4 and the distinctive shells form middens near their settlements 5 Littleneck clam Scientific classification Domain Eukaryota Kingdom Animalia Phylum Mollusca Class Bivalvia Order Venerida Superfamily Veneroidea Family Veneridae Genus Leukoma Species L staminea Binomial name Leukoma staminea Conrad 1837 1 Synonyms 1 Chione ruderataDeshayes 1853 Paphia staminea Conrad 1837 Paphia staminea orbella Carpenter 1864 Paphia staminea var sulculosaDall 1902 Protothaca grewingkiiDall 1904 Protothaca staminea Conrad 1837 Tapes diversaG B Sowerby II 1852 Tapes tumidaG B Sowerby II 1852 Tapes tumidaCarpenter 1857 Venerupis petitiDeshayes 1839 Venus ampliataCarpenter 1857 Venus conradiRomer 1867 Venus mundulusReeve 1863 Venus pectunculoidesValenciennes 1846 Venus rigidaGould 1850 Venus stamineaConrad 1837 Contents 1 Description 2 Distribution and habitat 3 Ecology 4 ReferencesDescription editLike other members of Veneridae this species has a chalky shell the umbo being anterior to the midline of the shell but closer to the midline than to the anterior end of the shell The two equal sized valves are oval or heart shaped The width of the shell is greater than a quarter of its length and the shell seldom exceeds 6 cm 2 4 in in length The umbones point towards the anterior end of the shell The hinge has three cardinal teeth in each valve and a row of small teeth along the ventral margins of the valves There are numerous concentric ridges more clearly demarcked at the anterior end but the radial ridges are often more clearly sculpted The foot is large and there is a clearcut pallial sinus 2 Right and left valve of the same specimen nbsp Right valve nbsp Left valveDistribution and habitat editLeukoma staminea is native to the eastern Pacific Ocean Its range extends along the coasts of North America from the Aleutian Islands and Alaska in the north to Baja California in the south It usually occurs in protected areas on sand hard mud and clayey gravel substrates from the mid and lower shore down to depths of about 10 m 33 ft usually buried less than 8 cm 3 in beneath the surface of the sediment Occasionally it is in more exposed locations in gravel filled cracks in rocks or in empty burrows of other clams 2 Ecology editThis clam is a filter feeder and consumes microscopic algae such as dinoflagellates diatoms and cyanobacteria 2 6 Some dinoflagellates produce neurotoxins such as saxitoxin and its derivates that bioaccumulate in the clams and other bivalve mollusks and can cause paralytic shellfish poisoning PSP when the clams are eaten 2 6 Despite this fact the clam was eaten by Native Americans and is still used as a food for humans 2 According to a 1996 report from the Marine Advisory Program at the University of Alaska the United States Food and Drug Administration FDA considers seafood unsafe if it contains more than 80 mg of PSP causing toxins per 100 g of tissue of the seafood 7 8 PSP is caused by a mixture of at least 21 different chemical species some of which undergo chemical transformations within the dinoflagellates or within the animals that acquire the saxitoxins and which are retained by different animals for different lengths of time 7 It is clear that PSP causing toxin levels are typically much higher in the summer months 9 though this does not mean the seafood is necessarily safe at other times 10 Risks also vary based on species 7 8 but seafood available for retail sale is required to meet the FDA standards 10 In PSP poisonings that occurred in the summer of 1993 in Kodiak Alaska saxitoxin levels as high as 19 600 mg 100 g were measured in the Alaska blue mussel Mytilus edulis sufficient to provide a lethal dose in a single 2 5 g mussel 7 By contrast the highest measured level of saxitoxin in the Pacific littleneck clam was 580 mg 100 g according to this 1996 report 8 Littleneck clams are typically less toxic and retain their toxins for a shorter amount of time than the other species such as butter clams and blue mussels that tend to accumulate the highest levels of PSP toxins and geoducks and scallops that tend to be toxic for longer periods of time but this does not mean that these clams are always safe to eat as you can get PSP from littleneck clams 11 The reason for the difference is likely that the littleneck clam has an enzyme that converts saxitoxin into decarbamoylsaxitoxin a capability not shared by the blue mussel nor by the butter clam Saxidomus gigantea in which levels of saxitoxin as high as 7 750 mg 100 g have been reported 8 12 This transformation to decarbomyl derivative has been reported in some other clam species and significantly reduces the toxicity of saxitoxins present 13 Predators include such molluscs as the leafy hornmouth snail Ceratostoma foliatum and Lewis s moon snail Neverita lewisii the crabs Metacarcinus magister and Cancer productus the giant Pacific octopus Enteroctopus dofleini and the sea otter 2 Fish such as the Pacific staghorn sculpin sometimes nips off the siphons when they are extended to feed This clam spawns during the summer in the north of its range It is a slow growing species and may live for up to sixteen years 2 References edit a b Huber Markus 2018 Bieler R Bouchet P Gofas S Marshall B Rosenberg G La Perna R Neubauer TA Sartori AF Schneider S Vos C ter Poorten JJ Taylor J Dijkstra H Finn J Bank R Neubert E Moretzsohn F Faber M Houart R Picton B Garcia Alvarez O eds Leukoma staminea Conrad 1837 MolluscaBase World Register of Marine Species Retrieved 29 December 2018 a b c d e f g h Cowles Dave 2007 Leukoma staminea Conrad 1857 Invertebrates of the Salish Sea Rosario Beach Marine Laboratory a campus of Walla Walla University Washington Retrieved 29 December 2018 Family Veneridae Venus Clams Gladys Archerd Shell Collection Washington State University Tri Cities Natural History Museum Retrieved 29 December 2018 Burnham C Michael 2008 Los Osos Back Bay The Megalithic Portal Retrieved 29 December 2018 Lightfoot Kent Parrish Otis 2009 California Indians and Their Environment An Introduction University of California Press p 271 ISBN 978 0 520 94228 8 a b Clark R F Williams S R Nordt S P Manoguerra A S 1999 A review of selected seafood poisonings PDF Undersea amp Hyperbaric Medicine 26 3 175 184 PMID 10485519 Archived from the original on June 17 2012 a href Template Cite journal html title Template Cite journal cite journal a CS1 maint unfit URL link a b c d RaLonde Raymond October 1996 Paralytic Shellfish Poisoning The Alaska Problem PDF Alaska s Maritime Resources Marine Advisory Board the University of Alaska pp 1 7 a b c d How Toxic Are Alaska s Most Common Shellfish PDF Alaska s Maritime Resources Marine Advisory Board the University of Alaska October 1996 pp 10 11 Gessner Brad October 1996 Epidemiology of Paralytic Shellfish Poisoning Outbreaks in Alaska PDF Alaska s Maritime Resources Marine Advisory Board the University of Alaska pp 16 17 19 a b Truths and Myths about PSP PDF Alaska s Maritime Resources Marine Advisory Board the University of Alaska October 1996 pp 14 15 Alaska Sea Grant Program 13 August 2015 Paralytic Shellfish Poisoning in Alaska Facts and Discussion College of Fisheries and Ocean Sciences at the University of Alaska Fairbanks Retrieved 22 January 2019 Sullivan John J Iwaoka Wayne T Liston John 1983 Enzymatic transformation of PSP toxins in the littleneck clam Protothaca staminea Biochemical and Biophysical Research Communications 114 2 465 472 doi 10 1016 0006 291X 83 90803 3 PMID 6882435 Deeds Jonathan R Landsberg Jan H Etheridge Stacey M Pitcher Grant C Longan Sara Watt 2008 Non Traditional Vectors for Paralytic Shellfish Poisoning Marine Drugs 6 2 308 348 doi 10 3390 md6020308 PMC 2525492 PMID 18728730 Retrieved from https en wikipedia org w index php title Leukoma staminea amp oldid 1160101775, wikipedia, wiki, book, books, library,
