Shares of Carnival (NYSE:CCL) sunk to a new 52-week low on Monday, partially due to the undertow of a volatile overall market. Industry turbulence has driven Carnival's shares down about 30% year to date, but the stock has already recovered a bit from recent lows. Though results remain tepid, Carnival is still a solid long-term hold for patient investors.

Today's second-quarter results, and an accompanying share-repurchase announcement, gave shareholders some relief. The good news prompted a 4% jump in the stock, to a recent $39.72.

Earnings for the quarter were down a penny from the same quarter last year, to $0.46 per diluted share. CEO Mickey Arison stated that high fuel costs shaved $0.09 off this quarter's earnings. The company did manage to increase revenues by 6%; strong growth trends in the cruise industry have fueled five years of steady top-line gains for Carnival.

Following its recently reduced guidance, Carnival expects full-year earnings of $2.65-$2.75 per share, for a forward P/E of about 15. Caribbean bookings continue to be weak, which is affecting net revenue yields. That's an industry term measuring "net revenue per available lower berth day" -- the cruise-line equivalent to same-store sales. Carnival maintained its lukewarm yield guidance for 1%-2% growth for the year.

In addition, management continues to repurchase stock. In addition to its recent repurchase of $967 million of stock, the company announced that it will buy back another $1 billion as appropriate. Since its merger with P&O Princess of England in 2003, Carnival is a dual-listed company, with Carnival plc (NYSE:CUK) shares trading both in London and in the U.S. as an ADR. As one might expect, the CUK shares are much less liquid, but both trade at a similar valuation, and management intends to repurchase both kinds of shares.

Carnival's results will always be influenced by changes in the weather, fuel, and geopolitical events, among other items beyond its control. Since it operates in the leisure industry, it's also subject to the whims of consumer confidence. People travel and vacation when they have larger amounts of discretionary income, which benefits cruise lines like Carnival, hotel chains, airlines, and even recreational boating companies like Motley Fool Hidden Gems pick Marine Products (NYSE:MPX). Currently, higher interest rates and gas prices are sapping consumers' willingness to splurge on vacations and recreation.

However, the long-term story remains intact. A small percentage of vacationers in the U.S have never cruised, and Europe and Asia are even more untapped. An aging population lends itself to more leisure time and discretionary spending. The cruise industry is an effective duopoly between Carnival and Royal Caribbean (NYSE:RCL), both of which expect continued growth. Its more conservative balance sheet and higher net margins make Carnival the stronger of the two rival cruise lines. (For a further comparison, check out our recent Foolish Face-off.)

Carnival is an industry leader with a good track record of profitable growth, and it should continue to reward long-term shareholders. There may be few upward surprises for the remaining 2006 results, but if this year's hurricane season passes without any major destruction, Caribbean bookings should pick up steam toward the end of the year.

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Fool contributor Ryan Fuhrmann has no financial interest in any company mentioned. Feel free to email him with feedback or to discuss any companies mentioned further. The Fool has an ironclad disclosure policy.