LAS VEGAS >> Las Vegas’ tourism sector is bracing for changes in the aftermath of the massacre that killed 58 people at an outdoor music festival.

Analysts who closely track the finances of the city’s casino companies say Las Vegas will see a short-term dip in visitors in response to the shooting.

Casinos and police may have to impose new security measures after gunman Stephen Paddock brought more than 20 rifles into his hotel room and drove a car filled with explosives into the parking garage.

The “What Happens in Vegas Stays in Vegas” slogan has been put on hold, as has one unveiled in the weeks before the shooting by the owner of Mandalay Bay that said, “We are not in the hotel business … we are in the holy s—- business.”

Electronic billboards that typically promote restaurants, concerts, a topless pool and other entertainment are now showing a dedicated phone line for victims and their families, along with words of appreciation for first responders and casino employees.

“We’ve been there for you during the good times. Thank you for being there for us now,” reads a black-and-white billboard message with the city skyline and “#VegasStrong.”

It’s hard to quantify the effect the shooting will have on Las Vegas tourism. Airplanes still carry loads of tourists to the desert oasis, convention-goers fill large halls to discuss the latest industry trends, and slot machines ring in the casinos.

But stock prices of the main Las Vegas casino companies all took a minor tumble after the shooting, in an indication the attack will have some effect on the industry. Analysts with investment bank Morgan Stanley forecast the shooting will decrease demand for the Las Vegas market for about six months and have a 4 percent to 6 percent economic effect.

The analysts looked into the effect of terrorist attacks on “revenue per available room,” a key gauge of a lodging company’s performance, across different markets to measure the shooting’s potential impact. The report said not all markets are alike, but the effects on tourism of events such as the Orlando, Florida, nightclub attack have gradually become less pronounced and shorter.

On Oct. 1, Paddock, a 64-year-old professional video poker player, shattered windows of his hotel suite on the 32nd floor of the Mandalay Bay hotel casino and unleashed withering gunfire at the Route 91 Harvest country music festival below before killing himself. His vehicle was found at the hotel’s massive parking garage with a potentially deadly cargo of 1,600 rounds of ammunition and 90 pounds of chemical explosives.

In the days after the shooting, visitors found marked police SUVs parked outside their hotels along the Strip. Security employees of the Wynn Las Vegas and Encore casino-resorts used hand-held metal detectors to check bags. Guards asked some visitors to pop their trunks.

But those measures have since been scaled back. A tour of several major resorts found no apparent new security measures other than guards checking room keys at Mandalay Bay.

Mandalay Bay’s parent company, MGM Resorts International, owns more than a dozen properties, including casinos, convention space and arenas on the Las Vegas Strip. Spokeswoman Debra DeShong said in a statement the company has elevated its level of security, but she declined to provide details.

Las Vegas hotel operators must make their guests feel valued and comfortable in the aftermath of the shooting, said Michael McCall, Michigan State University professor of hospitality business. He suggested resorts offer room upgrades or discounted tickets to customers as tokens of appreciation.

But he said many casinos and hotels will tread lightly when it comes to airport-style security in a city where people want to let loose.

“You don’t want it to become a sort of ground zero military-type of operation,” McCall said. “People are going there largely for fun.”

MGM declined to comment on any hotel room or convention cancellations. Caesars said its properties haven’t received out-of-norm room cancellations, and no conventions were called off.

Last week, the National Business Aviation Association convention drew around 27,000 people to Las Vegas. IMEX America, an expo for incentive travel, meetings and events, brought 12,000 attendees.

Luis Barros visited Las Vegas for the aviation conference. While sitting at an airport slot machine, he said he never considered canceling his trip after the shooting and had no concerns about his safety.

“I figured this is probably going to be one of the safest places after what just happened,” the Dallas resident said. “I think I’m more concerned about the somber feeling, but as far as security-wise, no, not at all.”

The shooting has altered at least one event. Organizers of the GEICO Rock ‘n’ Roll Marathon scheduled for November will no longer start the annual race outside Mandalay Bay or hold the pre-race concert at the venue where the shooting took place.

Las Vegas last year welcomed 42.9 million visitors and hosted almost 22,000 conventions. On average, 95 percent of the 149,339 rooms available were booked during weekends. Clark County recorded gambling revenue of $9.7 billion.

For the time being, the fierce competition for those dollars is not on display.

“There’s going to be a time when we go back to promoting Las Vegas as the greatest destination in the world, but that’s not now,” said the city’s top tourism official, Las Vegas Convention and Visitors Authority CEO Rossi Ralenkotter. “We need to take care of this, we need to take care of our customers, we need to take care of the community itself, and that’s what we will be doing.”