From Triathlon Canada:

Expression of Interest

An expression of interest is the mechanism by which athletes confirm their intention to compete and accept a place at the Age Group World Championships if they qualify. By expressing intent, the results can be filtered to a final list of athletes who wish to compete at the World Championships, and places can be “rolled-down”.  The application will open 3 weeks before each race and close the day before the event.

All athletes seeking to compete for a place must submit an Expression of Interest prior to each qualifying event. An online page will be available for each event and discipline on the Triathlon Canada event calendar.

There will be a $20 fee to complete the Expression of Interest to encourage only serious athletes to apply for a spot. The $20 will be considered a deposit for those who are successful in obtaining a spot and will be deducted from their race entry fee. The $20 fee will not be refunded for athletes who are not successful in obtaining a spot. However, it can be applied to a charity entry.