Say Hello to Good Bivalves: a Look at Mollusks

Spey Bivalve Mollusks

Mollusks are a phylum of soft-bodied animals lacking vertebrae and having often, but not always, a tough external shell. Scientists estimate between 50,000 and 120,000 unique species of mollusk scuttle about the planet, as they have for the last 500 million years. Though mollusks comprise nearly 23 percent of marine phyla, they also exist in freshwater habitats and on land. Mollusks differ as much in size and structure as they do in behavior and habitat.

Major classes of mollusk include our heroes the bivalves (more on those dandies in a minute), the gastropods (snails and slugs), the cephalopods (octopi and squids), and a host of others. Man has culled the phylum as a food source for centuries, but mollusks also give us imperial Tyrian purple dye, sea silk, mother-of-pearl, and the queen of gems and gem of queens: pearls.

Bivalve mollusks in particular are a notable bearer of pearls, though other species have been known to spin the odd pearl on occasion, too. Mussels, oysters, clams, and scallops are the bivalve champions and live up to the species’ name: each relies on a two-part hinged shell to protect its soft core. A statement in self-reliance, bivalves make their own shell by secreting a calcium-carbonate material that grows along with the inner structure. It is this same material, called nacre, which makes up a pearl.

As filter feeders, bivalve mollusks help purify the water around them by both gathering food and breathing through their gills. They play an integral part in the sustainability of aquatic and marine ecosystems, serving not only as prey and habitats for others, but also as harbingers of water quality and health. Like canaries in a coal mine, mollusks are very sensitive to changes in temperature and purity. Most bivalves bury themselves in sediment or attach to rough crags and rocks for protection. The roughly 9,200 different species of bivalves are spread from the balmy tropics to the frozen arctic, and from the blackest pits of the ocean to the sandy drifts of the shore.

To help protect these important organisms, many of which are threatened or endangered by pollutants and exploitation, Spey has launched a unique initiative to conserve mollusk populations. In homage to our namesake River Spey in Scotland, Spey supports campaigns that educate and empower local Scots to care for the river – home to a critically endangered species of freshwater pearl mussel. The River Spey is but one of the ecosystems suffering from a loss of native mussel populations. Together we can help safeguard the mollusk for generations to come.