If a bill approved by the California Assembly Health Committee passes the full state assembly, genetically modified fish sold in the state would have to be labeled as such.

Genetically modified (GM) fish is not yet sold in the U.S. but the FDA is considering approval of a GM Atlantic salmon. The salmon, which has been given the growth hormone gene of the faster-growing Pacific salmon, along with DNA from the ocean pout reaches maturity at twice the rate of normal Atlantic salmon, and requires 25 percent less food.

“Knowing whether our salmon is genetically engineered is important for a host of reasons, including risks to our native salmon species, and allowing consumers to make dietary choices consistent with concerns they may have for the environment, food safety, and religiously or ethically based dietary restrictions,” said Assemblyman Jared Huffman who introduced the bill.

The U.S. Food and Drug Administration categorizes genetically engineered animals, also called transgenic animals, as an "animal drug." They are held to the same health and safety requirements that already exist for conventionally bred animals treated with hormones or antibiotics. In the case of transgenic animals, the "drug" is a snippet of DNA.

The FDA does not require genetically engineered animals to be labeled as such unless the food product is 'materially different' from a conventional product. In this case, the genetically altered salmon is materially the same as natural salmon, so GMO labeling is not required. However if the FDA approves consumption of pork from a pig that has been genetically altered to provide meat containing omega-3 fatty acids, it would carry a GMO label because the meat is different from traditional pork.

In other cases you may not know if you are consuming GMO unless it is voluntarily provided by the producer or you live in a state that requires disclosure. The U.S. Department of Agriculture does have guidelines for labeling "natural meats," which would differentiate conventionally raised meat from non-transgenic animals.

While genetically engineered animals have not yet been approved for human consumption in the US, GMO crops have been approved for over a decade. Today, as much as 70% of processed foods contain GMO ingredients such as corn, soybeans, and canola oil. In the U.S., 95 – 85% of key crops are genetically modified. As with GMO animals, the FDA does not require that products containing plant-based GMOs be labeled as such.

Sources:

Food Navigator-USA

Chicago Tribune.

Los Angeles Times.

Food and Drug Administration.