Speaking at the ceremony, Chen proposed a "Spratly Initiative" calling for a peaceful solution to the disputed claims of the group and promoting marine conservation in the region, a presidential statement said.
"Facing the complicated and sensitive territorial and sovereignty disputes in the South China Sea, Taiwan urges the countries involved to peacefully resolve the issues" according to international regulations, the statement quoted Chen as saying.
You can't sincerely call for a peaceful resolution while making a visit that provokes other claimant. Vietnam and the Philippines have criticized the visit while Malaysia and Brunei have yet to respond. Yes, the 4 ASEAN member states claim the islands in whole or in part. The other claimant is China.
I think ASEAN should come together and make a strong collective claim over Spratly. Instead of claiming on individual national basis, ASEAN could designate the Spratly Islands as an ASEAN territory that belongs to all member states.