Towfish with reversibly variable hydrodynamic lift and towing line comprising the towfish

The invention relates to a body towed by a cable behind a vessel and commonly termed towfish, the towfish (12) comprising a supporting structure (23) configured to move in the water in a main horizontal direction (25), and at least one appendage (27) configured to generate a hydrodynamic lift (P) for the towfish (12) that is directed downwardly when the towfish (12) moves in the water under the effect of the towing, the appendage (27) being orientable in order to modify its lift. According to the invention, the towfish (12) comprises a stock (21) which is rotatable with respect to the supporting structure (23) about a horizontal axis (30) perpendicular to the main horizontal direction (25), the cable being fastened to the stock (21). An orientation (γ) of the appendage (27), allowing it to modify the lift (P), is dependent on an angle (β) formed between the stock (21) and the supporting structure (23) about the horizontal axis (30).