The fish, in the migration, transpose the steps or doors-sill, passing between the reservoirs or tanks, during piracema, swimming for blade d? descending water or jumping. The doors-sill or steps possess the purpose to control the permanence of levels d? water and to waste energy in the form of losses located with the turbulence in the tanks. The energy is wasted in order to favor the ascension of the fish without causing its fatigue (MARTINS, 2004). In figure 4 it is a representation of stairs with door-sill or step 4 Figure Conclusion bioengineering is one is an area of border between biology and the engineering, that it aims at, the solution of ambient problems through engineering techniques. These domnios start to appear from the expansion of the knowledge of the mechanisms of functioning of biological systems, in its different scales, allowing its control and manipulation, many times foreseen by means of computational simulations. Of same form that classic engineering can control and manipulate systems, for example, electric, mechanical, thermal or hydraulical, the new domnios of bioengineering foresee the control and manipulation of biological systems. The importance of the construction of structures is unquestionable that all aim at the reduction of the impacts caused for the hydroelectric plants constructed in the country. The fish throughout the River Wood, have direct influence in the life of the messengers, therefore, they are populations that live directly of fish, take off of the fish its source of survival, the fish for these populations beyond income source, also are used for the feeding. The STP are implanted to attenuate some decurrent negative effect of the slide bars of rivers, on the community of the fish (MARTINS, 2004). Although to be efficient, the STP cannot be friction as only solution for the effect of the barrages, more yes, to complement important when in set with others initiatives as the piscultura: maintenance, preservation or introduction of spawning of fishes places; adequate quality of water, time of residence to the fish in the reservoir; reduction of the anxidas areas; extravasores, turbines and ' ' bypasses' ' friendly; maintenance or introduction of ciliares bushes; preservation of the springs; control of fishes predatory, among others.