The continental slope hatchetfish, or Polyipnus clarus, is a saltwater and brackish fish belonging to the family Sternoptychidae. This fish is not well known to sport fishermen in Quebec due to its primarily oceanic distribution and small size. It is not a common target for sport fishing, but it plays an important ecological role in its natural habitat. Continental slope hatchetfish are generally found in the deep waters of continental slope areas, making them difficult to access for recreational anglers. Their fight is almost nonexistent due to their small size and discreet behavior.

The continental slope hatchetfish is a small fish with a laterally compressed body, giving it a hatchet-like appearance. Its color is generally silvery, which allows it to camouflage well in deep waters. The patterns on its body are faint, often limited to a bright iridescence under certain lights. The mouth is small and oriented upwards, adapted for capturing planktonic prey. The fins are transparent and barely visible, suited for an environment where discretion is key. The tail is slightly forked, facilitating quick movements. The scales are fine and delicate, falling off easily, which can complicate their identification. Young fish closely resemble adults but are often more translucent. There is no obvious sexual dimorphism during spawning, as males and females appear similar.

In Quebec, the continental slope hatchetfish is primarily found in the deep waters of the Gulf of St. Lawrence, although it is not abundant. It is absent from inland waters and lakes in Quebec. This species prefers slope areas where depth increases rapidly, limiting its distribution to maritime zones. Generally, it is more common in temperate to cold oceanic areas where it can find refuge and food.

The continental slope hatchetfish primarily inhabits the deep waters of continental slopes. It prefers environments where the depth is significant, often between 200 and 1000 meters. These fish are adapted to cold temperatures, typical of oceanic depths. They are generally found in open waters, away from structures like reefs or wrecks. Light is rare at these depths, making their habitat relatively dark. The species is well adapted to waters where pressure is high, influencing their distribution in areas far from the coast.

The reproduction of the continental slope hatchetfish generally occurs at depth, where conditions are stable. Spawning takes place in the warmer waters of the slopes, where eggs can develop safely. The larvae hatch and float to the surface, where they feed on plankton. As they grow, they gradually descend to the depths. Maturity is reached quickly, often in less than a year, allowing for frequent reproduction. The lifespan is relatively short, typically 2 to 3 years.

Spring → Spawning → Summer → Juvenile growth → Autumn → Maturity → Winter → Deep survival

The continental slope hatchetfish is a gregarious fish, often found in schools to protect itself from predators. It is not territorial and moves with currents to follow food sources. Sensitive to changes in light, it often remains deep during the day to avoid predators and rises at night to feed. Surface weather conditions have little effect on their behavior due to their deep habitat.

The diet of the continental slope hatchetfish is primarily planktonic. The young feed on phytoplankton and small larvae of invertebrates. As they grow, they consume more zooplankton, including copepods and other small crustaceans. Their diet is opportunistic and depends on the availability of prey in their deep environment. Seasonal changes have little influence on their diet, although they may follow the vertical migrations of plankton.

The seasons do not have a major impact on the behavior of the continental slope hatchetfish, given its deep habitat. In spring and summer, young fish may be found closer to the surface, but adults generally remain at consistent depths. Feeding activity is primarily nocturnal, regardless of the season, due to the vertical migration of plankton. Surface weather conditions such as pressure and wind have no notable influence on this species due to its usual depth.

Since fishing for the continental slope hatchetfish is not common, the choice of lures and colors is rarely relevant. However, if you are looking to observe or accidentally catch this species, lures mimicking small silvery fish might be effective in clearer waters. Natural and metallic colors are preferred to mimic their appearance.

To observe or handle the continental slope hatchetfish, a light rod is sufficient. A small reel with a 2 to 4 lb line may be suitable. Hooks should be small and thin to avoid damaging this delicate fish. A fluorocarbon leader can be used for its discretion in the water.

Due to their small size and fragility, handle the continental slope hatchetfish with care. Use wet hands to avoid damaging their delicate scales. If you need to release them back into the water, do so quickly to minimize stress. For photos, avoid taking them out of the water for too long.

The main aquatic predators of the continental slope hatchetfish include larger fish such as cod and halibut. Seabirds, while less frequent due to depth, may also prey on young fish when they are closer to the surface.

The continental slope hatchetfish is not an endangered species in Quebec, primarily due to its deep habitat and distance from human activities. Management of this species is low priority, but respecting marine ecosystems is crucial for its survival. Catch and release is advised when caught accidentally.