One professor's last hunt for Nessie

I was reading The Boston Globe the other day and came across this fascinating story.
It was about this professor who saw Nessie years ago and ever since then, he has been going back regularly to confirm his sighting. He goes with sonar equipment and it has picked up large, moving objects in the water.But, he hasn't had any luck recently. This makes him think that perhaps Nessie has passed away. He is going back one more time to try to make one last desperate grasp on whether Nessie has died, or is, or was, real at all.