This article looks at the modes of government of two species of highly migratory amphihalin fish: European eel (Anguilla anguilla) and Atlantic salmon (Salmo salar). Based on a long ethnographic survey, this text proposes to analyse the arrangements of the governments of fisheries and stocks in continental (western France) and ultramarine (Archipel de Saint-Pierre and Miquelon), demonstrating the globalisation faced by these species and their catch and consumption sectors. Species in decline, their protection was put on the top of the agenda in the second half of the 20th century, but problems emerge much earlier. Contemporary public action is therefore closely concerned with these two species, and seeks to develop appropriate public policies through various instruments. But these policies are often based on pre-existing policies, rather than drawing inspiration from other forms of government, which are now highlighted outside Western politics by an increasing variety of actors.