Mussels and scallops may look similar at first glance, but they are actually quite different. While both are bivalve mollusks found in salty waters, they belong to different families and have distinct characteristics when it comes to anatomy, habitat, culinary uses and more.
Appearance
The most noticeable difference between mussels and scallops is their shells. Mussel shells are elongated and asymmetrical, with one end rounded and one end pointed. They are typically dark blue, black, brown or greenish in color. Scallop shells are fan-shaped with ridges and scalloped edges. Their shells can vary greatly in color but are often pinkish, orange, white or purple.
On the inside, both mussels and scallops have a mantle that secretes the shell, along with gills for respiration and adductor muscles that allow the shell to open and close. However, the body size and appearance of the bivalves themselves differ. Mussels have a smooth, oblong body, while scallops have a more circular, corrugated body with visible eyes around the edges.
Habitat and Behavior
Mussels and scallops also occupy different marine habitats. Mussels attach themselves to rocks, docks, buoys or even each other using strong byssal threads. They prefer to live in intertidal zones where there is a mix of dry land and sea. Scallops are free-swimming and live on sandy or muddy bottoms offshore in depths up to 2000 feet. They can quickly close their shells and swim away from predators by expelling jets of water.
Mussels tend to live in large colonies or beds containing thousands of individuals. They are filter feeders, drawing in water through their shells and eating plankton and organic particles. Scallops are generally solitary, though some species may congregate when spawning. Scallops are also filter feeders but their mobility allows them to be more selective in finding ideal feeding spots.
Life Cycle
The reproductive cycle of mussels and scallops also differs. Mussels breed prolifically, fertilizing eggs and sperm by expelling them into the surrounding water. After fertilization occurs externally, larvae go through a trochophore stage followed by a veliger stage where they float and develop shells. Within 2-3 weeks, young mussels settle on a surface and attach themselves.
Scallops have separate sexes and fertilization happens internally after the release of eggs and sperm. The fertilized eggs develop into free-swimming larvae called veligers that can drift for weeks before settling on the seafloor. It takes 2-4 years for scallops to reach sexual maturity compared to just 8-12 months for mussels.
Culinary Uses
Both mussels and scallops are popular seafood options consumed around the world:
Mussels
- Typically eaten steamed, boiled, baked or roasted
- Added to pasta, curry, paella and stew dishes
- Served smoked or marinated
- Used to make broths and chowders
Scallops
- Often pan seared or fried
- Added to pasta, salad, skewers and risottos
- Eaten raw as sushi or sashimi
- Served in soups and stews
Scallops tend to be considered more of a delicacy, reflected in their higher cost. Their sweet, succulent taste makes them highly sought after. Mussels have a more earthy, briny flavor and starchy texture.
Nutrition
Mussels and scallops are both low in fat and calories while providing protein, vitamins and minerals:
| Nutrient | Mussels | Scallops |
|---|---|---|
| Calories | 86 kcal (for 3 oz) | 75 kcal (for 3 oz) |
| Protein | 12 g | 14 g |
| Fat | 2 g | 1 g |
| Carbs | 6 g | 3 g |
| Vitamin B12 | 16% DV | 330% DV |
| Selenium | 44% DV | 41% DV |
Scallops are very high in vitamin B12 and also provide iron and magnesium. Mussels have high amounts of vitamins C, B12, A and selenium. Both are considered good sources of omega-3 fatty acids.
Sustainability
Due to high demand, both mussels and scallops are at risk of overfishing. However, mussels tend to be more sustainably farmed and harvested than scallops. Methods of scallop fishing like dredging can damage sea floors. But regulations are strengthening to improve scallop fishing practices.
Mussels actually help improve water quality as they filter impurities. Ecological mussel farming creates reef-like beds that provide habitat for other marine life. So mussels are generally regarded as one of the most eco-friendly seafood choices.
Food Safety
As filter feeders, both mussels and scallops can accumulate toxins or contaminants from the water. This means proper handling is important to avoid foodborne illness. When buying:
- Look for tightly closed shells, which indicate freshness.
- Make sure they are still alive before cooking.
- Discard any with cracked shells.
- Store in a container in the refrigerator and use within 2 days.
Cooking thoroughly will kill potentially harmful bacteria. People with compromised immune systems may want to avoid raw scallops or mussels because of infection risk.
Allergy Concerns
Both mussels and scallops are mollusks and can trigger an allergic reaction in some people. Signs of an allergy include:
- Tingling or itching in the mouth
- Hives, rash or swelling of lips/face
- Wheezing, chest tightness, difficulty breathing
- Stomach cramps, vomiting or diarrhea
Anyone with a shellfish allergy should avoid mussels and scallops altogether and carry epinephrine if they have a severe reaction. For non-allergic people, moderation is still advised as high intake of shellfish may increase gout risk.
Price Differences
Scallops have a reputation as a luxury item and carry a higher price tag than mussels. A few factors contribute to the pricing disparity:
- Global demand for tasty, versatile scallops is very high.
- Wild scallop supply can be inconsistent year to year.
- Labor-intensive diver harvesting is common for scallops.
- Scallops take longer to reach market size than quickly growing mussels.
Prices do fluctuate based on the scallop species, harvest location and time of year. But generally expect to pay at least double the cost per pound for scallops compared to mussels.
Conclusion
While they look somewhat alike, mussels and scallops have notable differences when it comes to biology, ecology, culinary uses and economics. Mussels tend to be much more affordable and sustainable, providing an accessible source of protein and nutrients. Prized scallops fetch higher prices thanks to their sweet flavor and delicate texture that makes them a favorite indulgence.
Both have a place in seafood markets and menus around the world. Understanding their unique characteristics helps consumers select, prepare and enjoy these tasty bivalve mollusks in the kitchen and beyond.
