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- Sustainability Summary
Mediterranean mussels are most common in Europe, but are now grown on the Pacific coast of North America. Mussels are sold live and frozen as whole cooked, meats, and cooked on the half shell. Buyers should adopt a seasonal strategy because meat content decreases dramatically after mussels spawn: blue mussels are at their peak in winter and early spring while Mediterranean mussels are better in the spring, summer, and fall. Generally, rope-grown mussels have thin, clean shells and high meat content. Some producers hold mussels in tanks of water that are treated with ultraviolet light which destroys harmful bacteria, a process known as "depuration."
- Meat (cooked)
Health & Nutrition
- Total Fat4.48g
Mediterranean mussels look similar to blue mussels but have a few small differences in physical appearance. They tend to grow larger than blue mussels and their mantle edge is darker, becoming blue or purple. They are also known as the black mussel because their shell can be dark blue, brown, or an almost black color. Their two valves are equal in size, each rounded with a slightly bent edge. They can grow an average between 2-3 in (5-8 cm) but can grow up to 6 in (15 cm). Intertidal mussels are usually smaller, rarely exceeding 2.4 in (6 cm), while deep-water mussels can easily grow up to 3.5 in (9 cm).
Mediterranean mussels grow quickly, capable of reaching nearly 3 in (7 cm) within the first year of growth in favorable conditions. They have high fecundity, capable of reproducing multiple times per year and reaching sexual maturity at 1-2 years. They reproduce via broadcast spawning, releasing their gametes into the water column. Fertilized eggs will develop into free-swimming larvae, which will then attach to rocks. In California, spawning and recruitment occurs year-round, with the heaviest being from February-April and again from September-October.
Mediterranean mussels are ecologically important in coastal ecosystems and are considered “ecosystem engineers,” as their beds provide shoreline protection and important habitat and shelter for many species. They are suspension feeders, feeding on detritus and phytoplankton like green algae, dinoflagellates, and diatoms through their gills. As filter feeders, they help remove pollutants from the water. Mediterranean mussels are also an important food source for other species, like sea stars and birds such as seagulls.
Wild Mediterranean mussels’ exact range in the wild is unknown because of the confusion with other similar-looking Mytilus species. They are mostly found in temperate waters on exposed and sheltered intertidal rocky shores down to 131 ft (40 m) deep. In California they are principally found south of the Monterey Peninsula. In Europe they live on all coasts with hard substrates. They attach to these rocks using strong byssal threads and can create dense masses whenever the conditions are suitable. In general, they can withstand large fluctuations in salinity, desiccation, temperature, and oxygen levels.
In California, hybridization has been documented between Mediterranean and Baltic mussels in an area between Cape Mendocino and Monterey Peninsula. However, studies using DNA markers have even found hybrids as far north as Whidbey Island in Washington and as far south as San Diego Bay.
Research surrounding aquaculture, the potential for food production, and increasing market demand for shellfish has produced new technologies and harvest alternatives. Research was conducted on harvesting naturally occurring Mediterranean mussels from offshore oil production platforms in the Santa Barbara Channel in 1979. While controlling biofouling on these platforms, divers found that both Mediterranean and California mussels were growing in various stages of succession, including settlement. Commercially harvesting mussels from oil platforms became significant in the 1980s but this has stopped in recent years. New aquaculture technology also produces triploid and tetraploid (sterile) mussels, eliminating the risk of escape to wild populations.Management:
Today, Mediterranean mussels are almost exclusively farmed, although some wild harvest does still occur. Wild capture developed into a thriving industry in the 1950s, with the highest total catch reported in 1999 at 55,819 tons. Italy (37,876 tons) and Greece (15,860 tons) had the largest catches. Wild harvest dropped off significantly in 2005, while farmed Mediterranean mussels have gradually increased since the 1970s.
In 2016, global Mediterranean mussel aquaculture farms produced 105,331 tons, with the highest in 2003 at 147,468 tons. Farmed Mediterranean mussels are grown in off-bottom culture, on vertical lines in the water column. The ropes are lifted during harvest using booms over a boat deck.
US Mediterranean mussel aquaculture is regulated by federal, state, and local agencies including:
- Army Corps of Engineers (lead agency)
- US Fish & Wildlife Service
- US Department of Agriculture
- Food & Drug Administration
- California Department of Public Health Services
- California Department of Fish & Wildlife
- County Department of Public Health
Mediterranean mussel aquaculture production in California primarily occurs in southern and south-central California, which has greatly increased since the 1980s.
Mussels are often raised on ropes submersed in coastal areas, a system considered to be one of the most environmentally friendly forms of aquaculture. They are also bottom cultured and harvested by dredging, which can degrade sediment and cause a decline in biodiversity. However, dredging cultured beds causes less damage than dredging natural ones. Although they are filterfeeders that improve water quality, mussels will only thrive in a healthy environment. Harmful algal toxins in the water have caused some mussel farming areas to be closed temporarily.
Mussel farms tend to be protected from duck predators with fine mesh that is heavily weighted to avoid problems there with entanglements.
Mussels are filterfeeders that take in plankton so no extra feed is needed to grow them.
Disease, Pathogen and Parasite Interaction
Disease incidence among mussels is low.
Escapes and Introduced Species
Mussels are generally farmed in areas where they are native and interbreeding between wild and escaped mussels doesn’t threaten the wild populations. Mediterranean mussels farmed in the U.S. are considered a naturalized species.
|Acuacultura Integral de Baja California SA||Mexico||Baja California|
|Allen Shellfish||United States||Washington|
|Allseas Fisheries Corp.||Canada||Ontario|
|Baja Shellfish Farms||Mexico||Baja California|
|Carlsbad Aquafarm, Inc.||United States||California|
|Catalina Sea Ranch||United States||California|
|DiCarlo Seafood Company||United States||California|
|Fanny Bay Oysters||Canada||British Columbia|
|Flying Fish Company||United States||Oregon|
|Intercity Packers Meat & Seafood||Canada||British Columbia|
|Island Sea Farms, Inc.||Canada||British Columbia|
|Marinelli Shellfish Co.||United States||Washington|
|Monterey Fish Market||United States||California|
|OM Seafood Company||United States||Oregon|
|Organic Ocean Seafood Inc.||Canada||British Columbia|
|Out Landish Shellfish Guild||Canada||British Columbia|
|Pacific Harvest Seafoods||United States||California|
|Pacific Seafood Group, Inc.||United States||Oregon|
|Penn Cove Shellfish, LLC.||United States||Washington|
|Royal Hawaiian Seafood||United States||California|
|Sailor's Seafoods||Canada||British Columbia|
|Smokey Bay Seafood Company, Ltd.||Canada||British Columbia|
|Taylor Shellfish Farms, Inc||United States||Washington|
|Wixter Market||United States||Illinois|
- Environmental Defense Fund
- Food and Agriculture Organization of the U.N. (FAO)
- Seafood Watch Program