UPDATE 1-US FDA staff--Aqua Bounty biotech salmon OK to eat

* Fish appear same as normal Atlantic salmon - FDA staff

* Production unlikely to harm environment - FDA staff

* Manufacturer's shares gain 6 percent

WASHINGTON, Sept 3 (Reuters) - Aqua Bounty Technologies Inc's (ABTX.L) genetically engineered salmon are as safe to eat as normal Atlantic salmon, U.S. regulators said in a preliminary analysis released on Friday.

The fish, called AquAdvantage, are genetically altered to grow twice as fast as normal Atlantic salmon. The Food and Drug Administration is weighing whether to approve the fish for the U.S. market and is set to hold a three-day public meeting starting Sept. 19.

In documents released ahead of the meeting, FDA staff also said the fish were "highly unlikely" to produce significant effects on the environment.

Shares of Aqua Bounty rose 6 percent in London trading. (Reporting by Lisa Richwine, editing by Gerald E. McCormick) ((lisa.richwine@thomsonreuters.com; +1 202 310-5691; Reuters Messaging: lisa.richwine.reuters.com@reuters.net))