The authors conclude that small numbers of lake trout spawned successfully each year during 1992-97 in Lake Ontario, although this has yet to result in a trend of increasing natural reproduction. Juxtaposed with the high abundance of mature fish (Selgeby et al., 1995), the situation in Lake Ontario suggests a reduction in reproductive efficiency. This could result from mortality factors that may to a certain extent be density independent because recruitment has remained flat in the face of increasing spawner abundance. According to RESTORE, such factors are likely acting during the first year of life. Accordingly, the authors herin review the evidence that former barriers to lake trout reproduction in Lake Ontario that act as early-life-stage bottlenecks have been removed. In addition, the authors review other potential new barriers for which there has only recently been enough information to judge their relative importance.