Pike reproduction occurs in winter, with males reaching sexual maturity around the 2nd/3rd year and females around the 3rd/4th year. 
A female pike can produce up to 20,000 eggs per kilogram of body weight; from these data, one can understand the importance of protecting larger pikes (as breeding females) rather than the "small fry," as most obsolete regulations stipulate, with the obligatory famous minimum size. Let's give an example: a 10-year-old female can weigh over 10 kg (and exceed 100 cm in length), so she could lay about 200,000 eggs, a true repopulation! Males usually arrive in spawning areas before females, preferably choosing environments abundant in submerged and emergent vegetation such as grass or reeds, usually in shallow waters.
During this period, it may happen to see males forming small groups, an unusual behavior for pike. During the breeding period, the pike feeds inconsistently or sparingly. The spawning period occurs between January and April, when the fish perceives the right photoperiod, and the water temperature drops below 10°C. However, this period is very flexible and is also influenced by other environmental and climatic factors. 
Generally, the eggs are laid in clean, vegetation-rich waters; they are attached to aquatic plants by adhesive filaments, and in the absence of vegetation, they can be laid on rocks or submerged logs. They will subsequently be fertilized by the male or by several males. The hatching of the eggs occurs after about three weeks, and the survival rate of the fry is very low. In a few days, the yolk sac, the only source of nourishment for the young pike, is completely absorbed, and the first predatory instincts towards small crustaceans, larvae, and other small fish immediately begin to manifest. In the first months, the voracity of the pike is very pronounced, as is its growth rate.
This rapid growth is essential to allow the species to survive; in fact, the small pike is preyed upon by other fish and predatory birds such as cormorants, growing quickly will quickly remove it from these dangerous situations. The right temperature and the appropriate environment are fundamental factors for the reproduction of this species. Indeed, among the factors contributing to the reduction of pike presence in our waters are pollution (chemical spills, pollutants, agricultural pesticides), high temperatures due to climate change, and improper water management by the authorities, which rapidly alter the water levels of lakes and rivers, modifying the pike's habitat, making it inhospitable, and often rendering reproduction sites unusable. 
Another problem caused by improper water management is the cementing of the banks; this significant alteration reduces or eliminates the natural shelters where these fish normally stay and, consequently, can make the "spawning beds" disappear where the esocid goes to reproduce. 
In extreme cases, these situations interact so negatively on pike reproduction that they completely "skip" the breeding season, with very heavy repercussions on future generations.
These issues, combined with indiscriminate poaching and professional fishing, are causing pike to become endangered in some Italian waters. 
Adriano Marini
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