The cod of the seas is increasingly scarce and smaller. The size of adult specimens has decreased by 20% since the 1960s. A study conducted in the Gulf of Saint Lawrence, Canada, has concluded that overfishing is the main engine of it. As they have explained, in the networks that use for the capture of cod the largest specimens are taken, being in the sea small cod. Those who grow slowly among these little ones have more possibilities to mature and reproduce before being captured by fishermen. With the passage of time, the descendants of these little ones have predominated in the population.