Pacific Razor Clam

This species has an elongated oval narrow shell, which ranges from 8 to 15 cm (3 to 6 in) in length in the southern portion of its range, with individuals up to 28 cm (11 in) found in Alaska. The shell colour varies depending on the age and size of the clam. While young, it is a shade of light brown, and it becomes yellower as it approaches medium size. Following growth past the medium size, and approaching the larger size of clam, it reverts to its brown colouring. The two main parts of the clam are the shell, which has a zipper-like manifold that helps with growth, and the foot/siphon, which helps the clam manouevre in sand, as well as eat food. It is similar to the smaller Atlantic razor clam, Siliqua costata, which is found on the East Coast of the United States and Europe.

Pacific razor clams can be found along the West Coast of the United States and Canada, and have been found from Alaska to California. They are present along sandy beaches, and are found less than 30 feet (9.1 m) below the water, which is a stark contrast to Siliqua sloati, a different species of razor clam. The Pacific razor clam lives within these sandy beaches by burrowing down with their strong "feet". The clam orients itself towards the sand, and pushes down with its foot, and closes a valve inside its shell, pushing out their other end, and moving the clam downwards. This continues until the clam is fully submerged in the sand.

The Pacific razor clam feeds on a variety of phytoplankton, which may include diatoms, which are known to produce domoic acid, a key factor in safely consuming razor clams. As a filter feeder, the Pacific razor clam relies on its siphon to create a vacuum, which then sucks up the plankton of choice. As a result of this feeding, the Pacific razor clam is left vulnerable to the effects of microplastics and other contaminated material.

The Pacific razor clam is a sexually dimorphic organism, meaning that there are differences between the two sexes of animals. Fertilisation is an indirect action, meaning that no mating rituals or sexual intercourse occurs. The fertilisation of eggs will occur when the temperature of surrounding water is warmer. Males will deposit their sperm into sea water or sand, and females will do the same with their eggs. As the size of female razor clams increases, the number of eggs deposited into sea water and sand also increases. It is speculated that female Pacific razor clams can deposit up to 118.5 million eggs at one time. Though fertilisation of the eggs occurs by happenstance, the number of eggs deposited means that there is increased probability of fertilisation.

Pacific razor clams are a highly desirable shellfish species and are collected by both commercial and recreational harvesters. Razor clams, like other shellfish, may accumulate dangerous levels of the marine toxin domoic acid because of their diet, which consists of diatoms. Domoic acid can cause amnesic shellfish poisoning (ASP). Harvesters should check current public health recommendations by marine authorities before collecting razor clams. A longitudinal study found that individuals consuming 15 or more razor clams per month scored significantly lower on verbal memory tests compared to non-consumers, though all scores remained within normal clinical limits.

Razor clams are commonly battered and fried in butter. They can also be used to make clam chowder.