MOLLUSKS AND HUMANS / MOLLUSKS AND THE ENVIRONMENT
PANEL 3 – MOLLUSKS AND HUMANS
Mollusks have been part of human history since prehistoric times and continue to play an important role as an economic resource and cultural heritage for many societies.
Fishing and Mollusk Farming
Bivalves are the main group used in mollusk farming, both in freshwater and marine environments. This activity is known as malacoculture, and mussels, oysters, and scallops are the most common species cultivated.
Gastropods, like escargots, are also farmed on a large scale. Although cephalopods are widely consumed, they are still mostly obtained through fishing or gathering, as farming methods for these animals are still limited.
Oysters
Mussels
Mollusks in Cuisine
For thousands of years, mollusks have been part of the human diet—especially among coastal populations.
Polvo à lagareiro – Portuguese cuisine
Paella – Spanish cuisine
Escargot – French cuisine
Archaeology and Paleontology
Sambaquis (Shell Mounds) are archaeological sites built by coastal peoples during prehistoric times and can be over 8,000 years old. These mounds are made of layers of shells, sand, and soil, contain traces of ancient human activity, such as tools, hearth remains, animal bones, and human burials. Ammonites are a well-known group of extinct mollusks, famous as index fossils in paleontology due to their wide distribution and beautifully ornamented spiral shells.
They were cephalopods, like squids and octopuses, but had coiled shells like modern nautilus.
Sambaqui in Laguna, Santa Catarina – Brazil
Ammonite fossil
Mollusks In Human Cultures
Making our skin softer
Snails and slugs are widely used in the cosmetics industry to produce creams and facial masks. The mucus they produce is rich in vitamins A and E, mucin, antioxidants, collagen, elastin, and hyaluronic acid.
From cream jars to home décor
The diverse shapes, colors, and sizes of mollusks have long inspired artists.
In Ancient Greece and Rome, the purple color of royal robes came from pigments extracted from sea slugs—the same pigment later used in biblical iconography.
Pearl necklace
Hexaplex trunculus
Hey, you there, can I have a mollusk?
Indigenous peoples of North America used whelk and quahog shells (a type of bivalve) to make beads known as wampum.
In parts of Africa, Asia, and Oceania, cowrie shells (also known as cauris) were used as currency as early as the 11th century BCE— a practice that lasted in some places until the 19th century.
Cauris Monetaria caputophidii
Wampum
Every culture has its mollusk, its shells, and its meanings
During Christian baptisms, a bivalve shell was traditionally used to pour holy water over the person being baptized, symbolizing divine protection.
In Greek mythology, the goddess Aphrodite was said to have emerged from the sea on a giant mother-of-pearl shell—a shiny, calcified substance that lines the inside of some mollusk shells, likely from a bivalve of the Cypraea group, on the island of Cyprus.
Cephalopods also appear in legends and myths from Greek and Norse traditions. The sea monster Kraken, resembling a giant squid or octopus, was said to destroy ships and devour their crews.
Aphrodite on a mother-of-pearl shell
Kraken
PANEL 4 – MOLLUSKS AND THE ENVIRONMENT
Mollusks are diverse animals found in almost every environment: in the sea, rivers, lakes, forests, and gardens. The only place you will not find a mollusk is flying! They are nature’s allies and help maintain ecosystem balance.
Mollusks and Nature
Mollusks are important for maintaining nature’s balance in several ways:
- Feeding and energy transfer:
They have a wide variety of diets and are part of food webs for many animals—sometimes even forming part of the food chain of other mollusks. - Water filtration:
Some species, such as oysters and mussels, filter particles from the water as they feed. This helps clean the water and maintain ecological balance. However, they can also absorb toxic substances and store them in their bodies, which is why they are called bioindicators of water quality.
Mussel bed (Brachidontes and Perna perna) with green algae “sea lettuce” (Ulva lactuca)
Photo: Igor C. Miyahira
Healthy soil
Snails and slugs help decompose organic matter by feeding on dead plants. Their waste enriches the soil with nutrients. However, some species can become pests in crops and gardens because they feed on many types of plants.
Drymaeus interpunctus – land snail
Photo: Mariano Pairet
Mollusks and Disease
Some freshwater mollusks can transmit diseases. One example is the snail from the genus Biomphalaria, which can host the parasite that causes schistosomiasis (also known as “snail fever”), a disease that affects millions of people in 78 countries. It mainly occurs in areas with poor sanitation and limited access to clean water. This is considered a neglected disease, as the people affected often suffer serious health consequences due to the lack of treatment and public attention.
Biomphalaria glabrata – host of the parasite Schistosoma mansoni
Photo: Lenita de Freitas Tallarico
Threats to Mollusks
Mollusks face serious threats to their survival—and the main culprit is human activity. Unsustainable exploitation of natural resources, industrialization, and rapid urban growth are damaging the environment. This leads to habitat loss and degradation, widespread pollution, the introduction of invasive species, and even contributes to climate change.
- In the sea: Coastal development, mangrove destruction, and pollution harm the habitats where mollusks live.
- In rivers and lakes: River course changes, dam construction, mining, and the use of pesticides contaminate aquatic environments.
- On land: Deforestation for agriculture and livestock destroys the natural habitat of land-dwelling mollusks.
Invasive species: a serious problem
Some mollusks are not native to Brazil, but they have arrived and spread quickly, causing harm to the environment and the economy. These species are called invasive exotics.
Here are some important examples in Brazil:
Golden mussel (Limnoperna fortunei):
Originally from Asia, it arrived in South America in the 1990s through ballast water used to stabilize ships. This mussel clings to surfaces like rocks, boats, and water pipes in hydroelectric plants. It also threatens native aquatic species by competing for space and food, disrupting established ecological relationships.
Photos: Igor C. Miyahira
Green mussel (Perna viridis):
Native to the Indo-Pacific region, it is spreading rapidly along the Brazilian coast. It can disrupt marine food webs by competing with local species.
Photo: Carlos Eduardo de Freitas Guimarães Filho
Giant African snail (Lissachatina fulica):
Brought to Brazil in the 1980s to replace escargot in cooking, it was not accepted and ended up being released into the wild. With no natural predators and a high reproductive rate, it became a pest.
This snail can carry the parasite Angiostrongylus cantonensis, which causes a type of meningitis. The disease cycle involves mollusks and rodents, and humans can be infected accidentally.
Photo: Clarisse Duarte da Rocha Ferreira Alves Lima da Silva