How should we influence Lieutenants to discontinue being sharks toward each other?

Teach them to compete against the standard and not each other. The best still rise but they don't do so while cutting their peers legs out from under them.

It’s the same for Officers, Warrants and NCOs. As others have said, competition can drive people to do things out of character or in some misguided goal to achieve future promotions. I had a Brigade Commander who was conducting my initial counseling as one of her Company Commanders. She said “I value officers who do what is best for the unit and the team, without seeking the spotlight of recognition.” By helping to lift up your peers, you will earn their respect and trust. It takes a strong Rater and Senior Rater to set the climate amount subordinate leaders. When the message is that teamwork is priority one, people get the message. Great question LT.

Wasnt my experience, but I think it entails having leaders being involved. You cant take credit for someone else's work if your boss saw who was doing the work. So my thought is that engaged leadership stops it. Not well worked out, but my initial opinion on the matter.