In February 2001, the "Niles Report" proposed an additional four modifications to the causeway project: to either replace the fishway, open the gates during peak fish migration, open the gates permanently, or replace the entire causeway with a bridge. An Environmental Impact Assessment study was commissioned in 2003 to develop and summarise these options, and on its completion in 2005, it announced the recognition of "Option 3" and "Option 4" as possible solutions. The first option had been ruled out following the evaluation of other fish passage models, which were deemed inapplicable to the river. The second, suggesting systematic gate-opening periods, was ruled out because of the inability to cater to every marine species' migration periods. Option 4 was split into three sub-options, mainly to list possible bridge lengths: 170, 280, and 315 metres (190, 310, and 344 yards). The provincial government later accepted the proposal on 6 December 2006, and selected "Option 4B" on 7 August 2007, which called for a bridge in the place of the causeway.