The City of Somerville may not be a sinking ship, but the rats are deserting it anyway, officials said.

The city’s 18-month campaign against their four-legged foes has resulted in a significant drop in reported rat sightings within New England’s most densely populated city.

“We want to see another season, but we are cautiously optimistic that these numbers show that the cooperation of the community and the policies we adopted, have reduced the rodent population in the city,” Mayor Joseph A. Curtatone said.

Since the city decided to go the mattresses against their furry four-legged foes, basic but aggressive measures have knocked down rodent sightings by one third during the last 12-month period compared to the year before.

There have been 24 rodent reports so far this year, officials said. By this time in 2014, they had 103 reports on their hands. 

Within the last 12 months, there has been a 36 percent decrease in reports, dropping from a whopping 584 sightings to 372 in the 12 months before.

Somerville’s interdepartmental Rodent Action Team — yes, the acronym is RAT — introduced new rodent-resistant trashcans and increased waste container licenses for restaurants and other businesses where rats tend to frequent. The City issued 622 such licenses in 2014, a huge leap from the 177 issued in 2013.

“By adding an inspector that we can dedicate to registering, inspecting and licensing Dumpsters, we have created an environment where it is much more difficult for rodents to access food in commercial trash, making it more difficult for them to survive and multiply,” said Goran Smiljic, the superintendent of Inspectional Services.  

The mild winter temperatures in 2011 through 2013 failed to knock back rodent population through natural selection, causing huge upticks in rat reports in Boston, New York and Chicago, according to a report put out by the city. But Boston pest control companies told Metro that this past winter was one of their busiest in memory

  “We are obviously a smaller city than Boston, but our (rodent report) numbers were basically parallel,” SomerStat Senior Analyst Liana Barlow said. “They were like two people skating next to each other. But starting last year, our numbers started to deviate noticeably.”

Officials said they use overlapping maps to keep track of where calls most frequently come from and distributed new uniform rodent-resistant trash carts to every house that receives city trash services back in June 2014. Pest control teams are aggressively baiting sewers and construction sites and are offering 2,000 homeowners a free one-time rodent control visit per year, officials said.

They have also enlisted the services of SenesTech Inc. on finding humane approaches to reducing and managing rodent fertility by using non-lethal bait that suppress the reproductive capability in rats.

“The thing we’re careful to point out is rodents are a problem in every city,” city spokeswoman and RAT member Denise Taylor said. “We will never be able to fully eradicate them, but we want to keep them at a level that doesn’t interfere with quality of life.”