AUGUSTA — State officials Wednesday recommended stricter limits on eating fish from Maine’s industrial rivers, citing tests that revealed levels of dioxin that were significantly higher than expected.

The changes, which stiffen existing recommendations for three rivers, were announced in a joint statement from the departments of Human Services, Environmental Protection and Inland Fisheries and Wildlife.

One change reduced the recommended allowable consumption of fish for the general public from two rivers. For fish from the Androscoggin River, the limit was lowered from 12 meals per year to two per year. For the Kennebec River below Skowhegan, an annual limit of five meals per year was introduced. A “meal” is defined as an eight-ounce serving.

Also, the West Branch of the Sebasticook River below Hartland was added to the list of waterways containing fish that should not be eaten by pregnant women and nursing mothers. Other rivers already in that category under a similar warning issued in 1987 are the Androscoggin, the Kennebec below Skowhegan, the Penobscot below Lincoln and the Presumpscot below Westbrook.

“These warnings reflect the best information we have to date and may themselves be revised as additional data becomes available,” said State Toxicologist Robert Frakes in the Human Services Department’s Bureau of Health.

Earlier this month, the Department of Environmental Protection released test results showing unexpectedly high levels of dioxin, which is a byproduct of chlorine used in paper mills, in the flesh of brown trout, bass and other fish species taken from the rivers.

Dioxin, which was first detected in Maine fish in 1984, has been linked to increased cancer rates and reproductive disorders in laboratory animals, but federal agencies disagree over safe levels for human consumption.

Frakes said the state restrictions are based on average dioxin levels in fish taken from the rivers and are designed to keep the potential cancer risk to less than one in 100,000 over the lifetime of an individual who consumes the maximum recommended amount.

Still, Frakes said that risk is “very small” compared with other cancer risks, such as cigarette smoking.

Wednesday’s announcement came barely a week before Maine’s open water fishing season opens on April 1.