The silver lamprey, although not well known to sport fishermen, plays an important ecological role in the aquatic ecosystems of Quebec. It is often perceived as a harmful species due to its parasitic nature, attaching to other fish to feed on their blood. However, it is fascinating for its complex life cycle and adaptation to various freshwater environments. Primarily distributed in the watersheds of the St. Lawrence and Outaouais rivers, it prefers cold, flowing waters. The silver lamprey is not a traditional sport fish, but it attracts interest for its unique behavior and distinct appearance.

The silver lamprey is distinguished by its elongated, eel-like body, lacking scales, typically measuring between 15 and 30 cm. Its color ranges from silvery gray to light brown, with a paler belly. Its mouth, shaped like a suction disc, is lined with keratinized teeth used for attaching to its hosts. The dorsal fins are underdeveloped, and it lacks pectoral and pelvic fins. The tail is rounded, providing it with some agility in the water. The young, called ammocoetes, are brown and live buried in the substrate for several years before metamorphosing into adults. The differences between males and females are not marked, even during spawning.

In Quebec, the silver lamprey is primarily found in the rivers of the St. Lawrence and Outaouais watersheds. It is less common in northern regions where conditions are more extreme. This species prefers rivers and streams with sandy or muddy substrates, where the young can bury themselves. Although it is widely distributed, its abundance can vary depending on water quality and the availability of hosts.

The silver lamprey thrives in sandy or muddy bottom rivers and streams, where the young can bury themselves to develop. It is usually found in flowing, well-oxygenated waters with moderate depth. It prefers cool temperatures, between 10 and 18 °C, and can tolerate slightly turbid waters. When searching for this animal, focus on areas with good flow and a substrate suitable for burying the young.

The reproduction of the silver lamprey occurs in spring when the water temperature reaches about 10 °C. Adults migrate to suitable rivers and streams to spawn. The female lays her eggs in nests dug into the substrate, often in shallow, well-oxygenated areas. After spawning, adults generally die. The eggs hatch within a few weeks, giving rise to ammocoetes, which remain buried in the sediment for several years, feeding on organic matter. Once metamorphosed, the young lampreys become parasitic and seek hosts to feed on. Spring → Spawning → Summer → Ammocoete growth → Fall → Metamorphosis → Winter → Parasitism

The silver lamprey is generally solitary, especially as an adult. Young ammocoetes live in groups in the substrate. It is not territorial but actively moves in search of hosts. Sensitive to changes in light, it is more active during low light periods, such as dawn or dusk. Weather conditions, such as atmospheric pressure and wind, have little impact on its behavior, although it prefers well-oxygenated waters.

Young ammocoetes of the silver lamprey feed on organic matter present in the substrate, such as plant debris and microorganisms. Once metamorphosed, adult lampreys become parasitic and attach to other fish to feed on their blood and bodily fluids. The diet does not vary much with the seasons, although parasitic activity may increase during host spawning periods.

In spring, the silver lamprey is active during spawning, migrating to suitable rivers. In summer, it actively continues its search for hosts in deeper, cooler waters. In fall, it remains parasitic but becomes less active as water temperatures drop. In winter, activity slows considerably, and it primarily remains attached to its hosts. The best times to observe it are early in the morning or late in the evening when light is low. Weather conditions have little impact on this species, but it prefers well-oxygenated waters.

Although the silver lamprey is not a target species for sport fishing, it can be observed using underwater cameras. In clear waters, natural colors like green and brown help camouflage the equipment better. In murky water, prefer brighter shades to facilitate observation. Lighting should be adjusted to avoid startling the lampreys.

For observing and studying the silver lamprey, a rod is not necessary. Prefer observation equipment like waterproof flashlights, underwater cameras, and sieves for sampling. If you need to handle lampreys, use gloves to avoid injuries from their keratinized teeth.

Handling the silver lamprey should be done carefully to avoid injuring it. Use gloves to gently grasp it by the body. If you wish to return it to the water, do so quickly to minimize stress. For photos, keep it underwater as much as possible to prevent it from drying out.

Natural predators of the silver lamprey include certain fish like pike and walleye, which may prey on young ammocoetes. Aquatic birds, such as herons, are also potential predators in shallow areas.

The silver lamprey is not considered a threatened species in Quebec. However, it is often viewed negatively due to its parasitic behavior. Management of this species primarily aims to control its population to protect host fish. Releasing it back into the water is generally not a concern for this species.