UPDATE 1-Cruise company Carnival forecasts profit below estimates, shares fall

fall@ (Adds details on forecast, results, shares)

Dec 20 (Reuters) - Carnival Corp, the world's largest cruise operator, on Thursday forecast first-quarter adjusted profit below Wall Street estimates, hurt by higher fuel costs and a strong dollar, sending its shares down 7 percent in early trading.

Carnival said it expects current-quarter adjusted profit of 40 cents to 44 cents per share. Analysts on average were expecting 45 cents per share, according to IBES data from Refinitiv.

The company also forecast first-quarter net revenue yields, a keenly watched metric that measures spending per available berth, to be flat.

The forecast dragged down shares of Carnival's rivals Royal Caribbean Cruises and Norwegian Cruise Line by about 3 percent.

The outlook overshadowed the cruise operator's slightly better-than-expected quarterly sales and profit.

The company's adjusted earnings were 70 cents per share, beating analysts' estimate of 69 cents.

Net revenue climbed 4.6 percent to $4.46 billion, above the average analyst estimate of $4.44 billion. (Reporting by Soundarya J in Bengaluru; Editing by Maju Samuel)