The helicopter search for 17-year-old Robert Merton was called off on Friday. RNAS Culdrose did not intend resuming the search this week.
A civil aircraft spotted a kayak on Thursday evening after the teenager had gone missing on Wednesday evening.
The search operation involved helicopters, emergency tugs, local vessels, tourist boats and passing shipping, all of which were on the lookout.
Robert is a well-known local gig rower and cricketer.
Search and rescue said that the area was large and so much time had elapsed that there was a decreasing likelihood of finding the Islander.