The Fascinating Life Cycle of Eels and Lampreys in Portugal's Waters
- mcoelho813
- Jan 26
- 4 min read
Eels and lampreys often confuse people because of their similar elongated shapes, but these creatures are very different in biology and behavior. In Portugal, the life cycles of these aquatic animals intersect with local traditions, especially eel fishing, which remains an important cultural and economic activity. This post explores the unique characteristics of eels and lampreys, their life journeys, and the significance of eel fishing in Portuguese waters.
Differences Between Lampreys and Eels
At first glance, lampreys and eels look alike due to their long, slender bodies. However, they belong to completely different groups of fish:
Lampreys are primitive, jawless fish with cartilaginous skeletons. They have circular, sucking mouths and lack scales. Many lampreys are parasitic, attaching themselves to other fish to feed. Lampreia is known as the 'Queen of the River'.
Sea lampreys are strong! They use their mouths to move rocks as big as a softball when building nests for spawning. One female sea lamprey can produce 100,000 eggs. About 10% survive, producing 10,000 new sea lampreys.
Eels are true bony fish with jaws, teeth, and scales. They are predators that hunt smaller fish and invertebrates.
Understanding these differences helps clarify why lampreys and eels have distinct roles in their ecosystems and why their life cycles vary so much.
The Remarkable Journey of the European Eel
The European eel, Anguilla anguilla, is the species most commonly found in Portuguese waters. Its life cycle is one of the most extraordinary in the animal kingdom.
Spawning in the Sargasso Sea
European eels spawn far from Portugal, in the Sargasso Sea near the Bahamas. After hatching, the larvae drift with ocean currents across the Atlantic Ocean, a journey that takes several months. This long migration brings them to the coasts of Europe, including Portugal.
Growth in Freshwater and Estuaries
Once they arrive, young eels, called glass eels due to their transparent bodies, enter rivers, lagoons, and estuaries. In Portugal, places like the Aveiro lagoon near Murtosa and the Minho River provide ideal habitats for their growth. Here, eels spend several years maturing in freshwater or brackish environments.
Migration Back to the Sea
When mature, eels return to the ocean to spawn, but the exact triggers for this migration remain a mystery. Scientists believe factors such as daylight hours in August, water temperature, and rainfall influence their timing. The migration happens mostly at night and in concentrated bursts called "runs," which last only a few days.
Lampreys in Portuguese Waters
Lampreys also inhabit Portuguese rivers and coastal waters, but their life cycle differs significantly from that of eels.
Lampreys begin life as larvae buried in river sediments, feeding on microscopic organic matter.
After several years, they metamorphose into adults with their characteristic sucking mouths.
Many lamprey species are parasitic, attaching to fish to feed on their blood and tissues.
They return to freshwater to spawn and die shortly after.
While lampreys are less well-known than eels, they play an important role in river ecosystems and have fascinated biologists for centuries. Arroz de lampreia. (Lamprey rice dish) The main ingredient in this traditional Portuguese stew is lamprey fish. The dish consists of sautéed onions, olive oil, wine, smoked sausage, rice, and lamprey, which is cut into smaller pieces and then marinated in a combination of vinegar, wine, various herbs, and its blood. This is a pricey meal. Lamprey (lampreia) is caught during its spawning migration from January to April in major rivers like the Minho, Lima, and Tagus. Due to declining populations, it is classified as "Vulnerable," leading to conservation efforts alongside traditional fishing. The biggest Lampreia festival is in Montemor-o-Velho during March. Thousands of visitors will taste traditional lamprey dishes and tasty snacks, made by local restaurants, as well as farm-fresh items for sale, handmade crafts, and vendors. My favorite restaurant in Portugal is called Lampreia. It is located in central Portugal. It is a large family-owned restaurant with lots of festivals held in its ballroom.
https://alampreia.com/ restuarant
Lampreia Facts
Royal Tradition: Historically, it was a dish for the upper class, with a long history of being served at banquets, including those of the Roman Empire and British royal coronations.
Bioindicators: Because they are sensitive to environmental changes and water pollution, they are used for long-term monitoring of water quality.
A "Monstrous" Delicacy: Despite their appearance, lampreys are considered a high-value gourmet ingredient in Portugal, Spain, France, Finland, and Latvia.
Folklore and Naming: They are often called "nine-eyed" (or flauta de sete olhos) due to their seven gill openings, one eye, and one nostril, which have appeared in European folklore, including as the inspiration for the "Lambton Worm".
Traditional Eel Fishing in Portugal
Fishing for eels is a long-standing tradition in Portugal, especially in regions like the Aveiro lagoon and the Minho River. The European eel is highly prized both locally and for export, but fishing is strictly regulated to protect the species, which has faced population declines.
Fishing Methods
Fishermen use specialized traps and nets designed to catch eels without harming other species. The fishing season usually peaks in late summer and early autumn, coinciding with the eels’ downstream migration.
Cultural Importance
Eel dishes are a staple in Portuguese cuisine, with many recipes passed down through generations. Despite some people disliking the taste of eel, it remains a beloved delicacy for many.
Why Eels Matter Beyond Fishing
The European eel’s complex life cycle highlights the delicate balance between freshwater and marine environments. Protecting eel populations requires international cooperation because their journey crosses multiple countries and habitats.
Efforts to regulate fishing, restore river habitats, and improve water quality are crucial to ensure eels continue to thrive in Portugal’s waters.
Recipes and cooking items
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