The Navy’s No. 2 officer has to contend with a $156 billion budget, complex global deployments and more than 400,000 active duty and reserve sailors. But one of his highest priorities these days is suicide prevention.

“This is at the top of my desk when I walk in,” said Adm. Mark Ferguson, vice chief of naval operations.

The mounting toll of suicide in the Navy, as in the other services, has become not just a collection of personal tragedies that deeply affect those in range, but a kind of enemy within. And knocking it down has become a “fundamental key to readiness,” Ferguson said.

In purely professional terms, losing a sailor to suicide deprives the ship of a contributor and saps morale and unit cohesion, he explained. This is particularly true in a ship’s tight and dangerous confines.

“We entrust our lives to those around us as a fundamental tenet of who we are,” Ferguson said.

Ferguson has been in his current job for a year. In October, his boss, the Navy’s top admiral, Jonathan W. Greenert, tapped Ferguson to take the lead on the suicide problem.

The Navy has not lost as many of its personnel to suicide as the other services have since the Sept. 11 terrorist attacks. But the service’s 51 suicides in 2011 and the 62 so far in 2012 have sounded the klaxon, he said.

As a former head of legislative affairs for the Navy, Ferguson is acutely aware of how many lawmakers are affected by the suicide scourge. He thinks Congress gives the Pentagon enough money to make inroads on the problem, but said the military needs a renewed focus.

He welcomes lawmakers’ attention to the issue — even their criticism.

“The pressure they sometimes put on us is a healthy pressure,” he said.