denatant and contranant movements.

Meek introduced these terms to describe the movements of fish in relation to the water current. Denatant means swimming, or drifting, or migrating with the current, contranatant means swimming or migrating against the current. To use the terms in connexion with the migration given in fig 1 (still to come), one would speak of the denatant migration of the pelagic eggs and the contranatant migration of the adults towards the spawning area. Now it is important to be clear as to what water current the adults are supposed to migrate against. The whole biological significance of the migration of the ripening fish is that it is in the opposite direction to the current which carries the eggs and the larvae away from the spawning area. Now it is important to be clear as to what water current the adults are supposed to migrate against.