California Mussel

Fascinating facts about the California Mussel

• The shell of the California mussel typically measures between 129 and 130 mm in length. Its exterior is a distinctive blue colour covered by a heavy brown periostracum that is usually worn away except at the growing edge of the shell; the shell is thick and bears coarse radial ribs and irregular growth lines, while the interior is blue and faintly pearly.
• In the 1950s the California mussel's shell was composed mainly of aragonite, but by 2017-2018 the dominant mineral had switched to calcite. This reversal was unexpected because rising ocean temperatures usually promote more aragonite, yet the mussel's shell chemistry changed in the opposite direction. Researchers attribute the shift to ocean acidification, noting that calcite is more resistant to acidic conditions than aragonite.
• When environmental conditions are favourable a California mussel can grow up to 200 mm in length and may live for more than twenty years. Despite this potential longevity, many individuals die much sooner because the intertidal zone subjects them to frequent wave pounding, driftwood impacts, desiccation, disease and predation by starfish such as Pisaster. These stresses make mortality rates high in open coastal habitats.
• Archaeologists have shown that peoples on the Northern Channel Islands relied on California mussels as a staple food for nearly twelve millennia, harvesting them without interruption. Evidence from San Miguel Island reveals that over the last ten thousand years the average shell size steadily shrank. Researchers linked this reduction to expanding human populations and the added pressure of fishing.
• The relationship between the starfish Pisaster ochraceus and the California mussel gave rise to the keystone species idea in 1969, when Robert T. Paine used it to illustrate how a single predator can control community structure.

Sources

Every fact above was checked against these pages, and kept only where one of them states it.

• Wikipedia

At a glance

About the California Mussel

In the turbulent intertidal zones of the Pacific coast, the California Mussel clings tenaciously to the rocky shores, its dark, iridescent shells a testament to its remarkable resilience. As the tide ebbs and flows, these mussels stretch and contract, their colonies forming a vibrant, pulsing tapestry that weaves together the very fabric of the ecosystem. With each wave, they filter the seawater with feathery precision, their gentle filtering a soothing serenade to the symphony of the sea.

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