Thanks to a recent downward trend, share price gains for Carnival (NYSE: CCL) (NYSE: CUK) are now running on empty over the past five-year period. Too bad its cruise ships can't also sail the seven seas on empty, because sky-high gasoline prices have wiped out strong continued trends in Carnival's cruise line business.

But don't count Carnival out just yet -- it did eke out a $0.01 increase in second-quarter earnings, to $0.49, on an impressive 16.5% gain in total revenue, but fuel costs took a $0.19 bite out of the bottom-line total. Pesky petrol trends also caused management to temper full-year guidance -- it's now calling for earnings of $2.70 to $2.80, down from $3.00 to $3.20 previously.

Speaking of top-line trends, net revenue yields continued to surge forward, improving in the mid- to high single digits. Bookings are also holding up, even though Carnival did concede that leisure travelers are becoming more price-conscious in this challenging consumer environment. Even with the worrisome near-term direction of fuel costs, the company is launching two new ships in its European fleet during the third quarter.

There's no telling if or when fuel prices might moderate, but Carnival is weathering the storm quite nicely so far. One cause for concern is that the company has paid out all of its earnings as dividends over the past six months, but I'll withhold judgment on this front, as management has historically been able to balance cash flow generation with growing its fleet, increasing dividends, and buying back shares.

Archrival Royal Caribbean (NYSE: RCL) is in the same boat, and while there's no denying the near-term environment is tough, Carnival and Royal operate an effective duopoly. Smaller niche industry players include Disney (NYSE: DIS), which runs a couple of cruise ships, and Steiner Leisure (Nasdaq: STNR), which offers on-board spa-related services. Given Carnival's stance atop an industry with favorable growth trends at its back, I'm quite content collecting a 4.5% dividend and waiting for fuel costs to cool down to more reasonable levels.  

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Fool contributor Ryan Fuhrmann is long shares of Royal Caribbean and Carnival, but has no financial interest in any other company mentioned. Feel free to email him with feedback or to discuss any companies mentioned further. The Fool has an ironclad disclosure policy.