The four-spined stickleback is a small freshwater fish found in several regions of Quebec, although it is not particularly sought after by sport fishermen. Its modest size and non-combative behavior make it a more interesting fish for observation than for sport. Nevertheless, it plays an important ecological role as prey for many aquatic and avian predators. Sticklebacks are common in calm, shallow waters, where they often move in groups. Their presence is a good indicator of the ecological health of a waterbody.

The four-spined stickleback is distinguished by its elongated, streamlined body covered in small smooth scales. As its name suggests, it has four prominent dorsal spines, a characteristic that sets it apart from its three-spined stickleback relatives. Its color ranges from olive green to brown, with silvery sides and a paler belly. The mouth is small and slightly turned upwards, adapted to feed on small invertebrates. The fins are generally transparent, and its tail is slightly forked. Males during the breeding season develop brighter colors, with reddish hues on the belly, while females retain a duller appearance. The young resemble adults but are smaller, with less developed spines.

In Quebec, the four-spined stickleback is present in the watersheds of the St. Lawrence River and Chaleurs Bay, as well as in some lakes and rivers in the Abitibi-Témiscamingue region. It is particularly abundant in calm, shallow waters where aquatic vegetation is dense. It is also found in estuaries and coastal marshes. Although it is widely distributed, it may be absent from faster or deeper waters, where it struggles to survive.

The four-spined stickleback prefers calm, shallow, well-oxygenated waters. It favors areas with dense aquatic vegetation that provide both food and shelter. It is often found near shorelines, marshes, and estuaries. This species can also adapt to slightly brackish environments, allowing it to live in estuaries. It generally avoids deep or fast-flowing waters, preferring sandy or muddy bottoms where it can easily hide.

The spawning of the four-spined stickleback occurs in spring when the water temperature reaches about 15 °C. Males build rudimentary nests from aquatic vegetation, often in shallow water. Once the nest is built, the male attracts a female to deposit her eggs. After spawning, the male guards the nest and protects the eggs until they hatch, which takes about a week. The fry grow quickly and reach sexual maturity in about a year. The lifespan of this species is relatively short, typically reaching 3 to 5 years.

Spring → Spawning and nesting → Summer → Rapid growth of juveniles → Autumn → Preparation for winter → Winter → Resting period

The four-spined stickleback is generally gregarious, forming small groups to protect themselves from predators. It is not particularly territorial, except during the breeding season when males actively defend their nests. Sensitive to environmental changes, the stickleback responds promptly to variations in light and noise. It may be more active on cloudy days or at dusk when light is diffuse. Winds and heavy rains can drive it to seek refuge in more sheltered areas.

The four-spined stickleback primarily feeds on small aquatic invertebrates, such as insect larvae, small crustaceans, and worms. Young sticklebacks mainly consume zooplankton until they are large enough to capture more substantial prey. As they grow, they diversify their diet to include aquatic insects and small mollusks. In winter, their feeding activity decreases, but they continue to eat whatever they can find under the ice.

In spring, the four-spined stickleback is particularly active during the spawning period, making it a good time to observe. In summer, it is more visible in shallow, vegetated waters, especially early in the morning and at the end of the day. Autumn marks a reduction in its activity, with a tendency to group in tighter schools. In winter, the stickleback slows its metabolism and seeks refuge in deeper areas or under the ice, becoming less visible. The best conditions for observation are clear, calm weather, although it can also be active on cloudy days.

For the four-spined stickleback, lures are not typically used, as it is not a species targeted by sport fishermen. However, if you wish to observe it, prefer areas with good visibility and use equipment that does not create too much disturbance in the water.

To observe or handle the four-spined stickleback, a light rod with a fast action can be used to minimize disturbances. A light reel and a 2 to 4 lb line are more than sufficient. Prefer small hooks to avoid injuring these small fish.

If you catch a four-spined stickleback, handle it carefully to avoid damaging its dorsal spines. Use wet hands or a damp cloth to hold it. Gently return it to the water to ensure its survival. Take a quick photo if necessary, but minimize the time out of the water.

The four-spined stickleback is preyed upon by many predators, including larger fish such as pike and perch. It is also hunted by aquatic birds such as herons and kingfishers. Mammals like minks may also feed on it.

The four-spined stickleback is currently stable in Quebec, with no concerning conservation status. However, habitat quality is essential for its survival. Regulations do not specifically target this species, but catch and release is encouraged to maintain natural populations.