contranatantadj.

1915 A. Meek in Nature 29 Apr. 231 To define these and other migrations which are intimately associated with currents it is necessary..to introduce two terms which will serve to indicate movement against the current and with the current. My colleague Professor J. Wight Duff recommends a Latin root, natare. The words suggested therefore are contranatant, swimming against the current, and denatant, swimming or drifting with the current. The words contranatation and denatation are also available to indicate the act or habit of migration against or with the current.

1959 A. Hardy Fish & Fisheries viii. 170 Most fish..make a migration up current before spawning and down current after spawning; these are technically known as contranatant and denatant migrations respectively.

1920 Rep. Dove Mar. Lab. 40 Evidence to support the theory of contranatation.