What happened

Shares of Carnival (CCL -4.08%) (CUK -3.93%) fell for the fourth consecutive time on Thursday. They declined in excess of 1.5% -- a steeper fall than the S&P 500 index, which was having a particularly tough day.

Fellow sailor Norwegian Cruise Line Holdings (NCLH -4.62%) also slipped. These movements were likely affected by a new research report on the cruise industry.

So what

Morgan Stanley analyst Jamie Rollo authored a report that was a good news/bad news take on the sector, with an accent on the latter.

Woman in hat on the deck of a cruise ship.

Image source: Getty Images.

Rollo believes that the industry will recover as vaccinations continue to increase and -- at least in some corners of the globe -- the coronavirus pandemic recedes. Inquiries and bookings "look positive," he wrote, with pricing being largely maintained.

On the down side, Rollo observes that travel agents surveyed by Morgan Stanley expect a full recovery will happen no sooner than in the first half of next year.

In his report, he explained that, "This slow return to service reflects continuously changing protocols from health authorities, the time required to move ships out of cold lay-up to where they need to be, the time required for crew staffing/vaccination/training, and the limited ports currently available."

Now what

Since Carnival and Norwegian are leading names in the seaborne tourism business, the dynamics Rollo describes particularly apply to them. We should also remember that due to the fast spread of the Delta variant, the world is far from done in the fight against the ever-threatening coronavirus.