However, the more stable
conditions resulting from hydropower utilisation can in some cases also cause an
increase in the growth of certain species. Hydropower facilities disrupt the natural
waterways. This will have effects on migrating animals, such as anadromous or
catadromous fish. Such obstructions can to some extent be circumvented by the
construction of fish way passes, such as different kind of ladders. All too often,
however, such measures appear to be inefficient, inappropriate, or prohibitively
expensive.