On the basis of hydroacoustic observations it is shown that migrations of krill during spring are stronger than during summer. Migrations of krill are described by the function: H(t) = A + Bcos((2ᴨt/T + φ ) + C c o s ( 2 ᴨt/T + φ ), where: H is depth of the mass center of krill biomass, A — mean depth of krill occurrence, В — amplitude of migrations with period T! = 24 h, С — amplitude of migrations with period T2 = 12 h, (φ1, φ2 — phases of migration process with T, = 24 and T2 = 12 hours. Parameters of the equation are the following: spring — A = 62.2 m, В = 19.5 m, С = 4.6 m, φ1 = 0.1 h, φ2 = 0 . 1 5 h; summer — A = 75.8 m, В = 0.5 m, С = 3.6 m, φ1 = 1.8 h, φ2 = 6.4 h.