2. Fishes in rivers and in the sea, are considered as animals ferae naturae, and consequently no one has any property in them until they have been captured; and, like other wild animals, if having been taken, they escape and. regain their liberty, the captor loses his property in them. Vide Ferae Naturae. The owner of a fishery in the lower part of a stream cannot construct any contrivance by which to obstruct the passage of fish up the stream. 5 Pick. R. 199.