In Europe, lobsters are commonly kept alive in tanks in restaurants, fishmongers, and supermarkets before being sold for food. Consumers believe this preserves their “freshness” and improves their taste. However, a group of scientists from Italy and the U.K. has reviewed existing research and concluded that aquarium conditions in these facilities are far from suitable based on what’s known about the animals’ natural behaviors, biological needs, and probable sentience.

Focusing on three key species, including the European lobster, the American lobster, and the European spiny lobster, the researchers looked at welfare-relevant studies to determine whether keeping these animals alive in tanks in commercial settings results in poor welfare. They used the well-known Five Freedoms framework from the World Organization for Animal Health, which requires that animals be:

1. Free from hunger, malnutrition, and thirst;
2. Free from fear and distress;
3. Free from heat stress or physical discomfort;
4. Free from pain, injury, and disease; and
5. Free to express normal patterns of behavior.

Based on these principles, the researchers identified a number of welfare concerns, ranging from stocking density to claw banding.

Stocking Density

European and American lobsters (or “true” lobsters) are solitary and highly territorial. Fighting occurs when a group is introduced to a new tank until a somewhat stable hierarchy is established. Still, being in close proximity to one another is likely very stressful for them.

In contrast, European spiny lobsters (also known as crayfishes or crawfishes) are more social and can tolerate living closer together. However, existing studies on stocking density tend to assess its effects on production traits like survival and growth rather than more welfare-relevant measures. More research is needed into the behavioral, physical, and physiological impacts of overcrowding on this species.

Light

Both true and spiny lobsters are adapted to living in darkness. Bright light can damage their eyes, though this also depends on other factors such as prior exposure.

All three species are nocturnal, meaning that exposure to constant or inappropriate lighting can disrupt their natural circadian rhythms and cause stress.

Shelter

True and spiny lobsters both prefer to spend most of their time in shelters. Spiny lobsters demonstrate clear preferences for certain shapes and sizes of shelter. For instance, one study found that most young spiny lobsters chose a semi-circular shelter (55%) over square (16.5%) or circular (11%) ones. For true lobsters, research shows they prefer shelters that are low, wide, and opaque rather than transparent.

Water Quality

True and spiny lobsters are sensitive to the properties of the water in which they’re kept. Low dissolved oxygen is associated with stress responses and increased susceptibility to parasites and pathogens. Deviations in environmental pH can impair enzymatic activity and the ability of the haemolymph (a substance in lobsters similar to blood) to carry oxygen. Trace metals can accumulate in their tissues and cause immunosuppression, and ammonia toxicity is also a concern. However, all three species can adapt to a wide temperature range.

Claw Banding

Elastic bands are routinely used on the claws of true lobsters to prevent them from injuring each other as well as the people handling them. However, this practice is harmful, as they use their claws to move around, feed, and defend themselves. Over time, the bands can cause muscle atrophy and weaken their claws during molting.

Recommendations

Based on these findings, the authors make several suggestions for improving the living conditions of these species in commercial settings.

• Reduce stocking density to no more than five individuals per square meter so that lobsters can avoid direct contact with each other. Keep true lobsters fully separate from one another by creating individual compartments within the tank.
• Provide each lobster with a shelter at least as long as their body. Keep the shelters clean so that poor hygiene doesn’t become an additional risk.
• Avoid having direct light above the tank and consider keeping it in complete darkness.
• Never band the claws of true lobsters, but instead focus on providing shelters and using aquarium partitions to reduce or eliminate fighting. Use tools like rubber-tipped pliers to avoid injury when handling them.
• Maintain water quality through filtration, aeration, and temperature control. Measure dissolved oxygen, temperature, pH, and ammonia daily or every other day, along with regular testing of nitrite, nitrate, and key metals.

While making these changes will improve lobster welfare, the authors ultimately encourage a ban on the sale of live lobsters to the public, which European consumers have already been shown to support.