The Atlantic sleeper shark, also known as the Greenland shark, is a fascinating and enigmatic fish of the cold waters of the North Atlantic. In Quebec, it is not a common target for sport fishermen due to its elusive nature and deep habitats. However, for those who venture into the icy waters of the St. Lawrence River and the Labrador Sea, encountering this giant can be an unforgettable experience. This shark is known for its exceptional longevity, living for several centuries. Its distribution in Quebec is primarily in deep marine areas, where its presence contributes to the balance of the marine ecosystem.

The Atlantic sleeper shark has a massive and elongated body, with rough and dark skin, usually gray-brown or blackish, allowing it to blend into deep waters. Its eyes are relatively small, adapted to the low light of great depths. It has a wide mouth with small, pointed teeth, suited to its varied diet. The pectoral fins are short and rounded, while the caudal fin is asymmetrical, with a longer upper lobe. Young sleeper sharks look similar to adults, although they are obviously smaller. There are no marked differences between males and females besides size, with females generally being larger.

In Quebec, the Atlantic sleeper shark is mainly found in the deep waters of the St. Lawrence River and the Labrador Sea. It prefers marine areas where the water temperature is cold, often below 12 °C. Although its presence is confirmed in these regions, it is not particularly abundant, making encounters with it quite rare. Its general distribution extends in the North Atlantic, covering areas from Greenland to Norway, and into Canadian waters.

The Atlantic sleeper shark primarily inhabits deep and cold waters, often several hundred meters below the surface. It prefers rocky or sandy seabeds, where it can move slowly in search of food. The ideal temperatures for this shark are generally between 0 and 12 °C, making it well-suited to the icy waters of the North Atlantic. To find it, one must search in areas where the depth often exceeds 200 meters, although it may be present at shallower depths during certain times of the year.

The Atlantic sleeper shark has an exceptionally long life cycle, with sexual maturity reached around 150 years. Reproduction is viviparous, with females giving birth to fully formed young. Litters are relatively small, often less than 10 pups. Growth is slow, but the longevity of these sharks is impressive, with some individuals living up to 400 years. This longevity is attributed to their slow metabolism and cold habitat.

Spring: Active hunting period in deep waters.

Summer: May venture into shallower waters.

Autumn: Returns to great depths.

Winter: Reduced activity, but continues to feed.

The Atlantic sleeper shark is a solitary and non-territorial predator, moving slowly in deep waters. It is not very responsive to noise and weather changes, which is typical of creatures living in stable and cold environments. The darkness of the deep means it is adapted to dim light, and it is not influenced by sunlight. This shark is opportunistic, feeding on available prey without showing aggressive behavior towards other species.

The diet of the Atlantic sleeper shark is varied and opportunistic. Young individuals primarily feed on small fish and invertebrates, while adults consume a wider variety of prey, including bottom fish, squid, and sometimes marine mammal carcasses. In winter, when prey availability decreases, it may rely on carrion, allowing it to survive in the harsh conditions of cold waters.

The Atlantic sleeper shark is active year-round, although its hunting activities may vary with the season. In spring and summer, it is more active and may venture into shallower waters to feed. In autumn, it begins to return to greater depths. In winter, its activity is reduced, but it continues to feed on carrion and opportunistic prey. Weather conditions have little impact on this shark due to its life in depth, but pressure changes may influence its vertical movements.

For the Atlantic sleeper shark, lures are generally not used as it is primarily attracted to natural baits. However, if you wish to experiment, prefer dark or natural colors that mimic bottom fish. In murky waters, phosphorescent lures may also be effective to attract this shark's attention in the dark.

To fish for the Atlantic sleeper shark, use a sturdy fishing rod measuring 2.4 to 3 meters long, with heavy power to handle the weight and potential strength of this shark. A spinning reel with a line capacity of 80 to 100 lb is recommended. Use large hooks, preferably stainless steel to resist corrosion, and a steel leader to prevent the shark from cutting the line with its teeth.

Handling an Atlantic sleeper shark can be difficult due to its size and strength. If you manage to catch one, it is crucial to handle it carefully to avoid injuring it. Use sturdy gloves and avoid taking it completely out of the water if possible. For a successful release, ensure the shark is well-oxygenated before gently letting it go. For photos, try to stay in the water to minimize stress on the fish.

In the waters of Quebec, the Atlantic sleeper shark has few natural predators due to its imposing size and deep habitat. However, orcas can sometimes prey on young individuals or weakened adults. Aside from that, threats mainly come from human activities, such as commercial fishing and pollution.

The Atlantic sleeper shark is currently classified as near threatened, mainly due to its slow growth and late maturity, making it vulnerable to overfishing. In Quebec, it is important to respect fishing regulations and practice catch and release whenever possible to contribute to the conservation of this unique species.