The discovery of two dead dolphins with grisly gunshot or stab wounds in Florida in recent weeks has prompted a plea for help by federal authorities, who have offered a reward for information about whoever killed the animals.

Biologists with the Florida Fish and Wildlife Conservation Commission found one male dolphin off Naples on Jan. 30, the National Oceanic and Atmospheric Administration Fisheries said Wednesday. The dolphin died from what appeared to be a bullet or a sharp object, the agency said. A photo of the animal showed a large, deep gash in its snout.

That same week, workers for the Emerald Coast Wildlife Refuge near Pensacola found another male dolphin with a bullet wound on its left side lying on the beach.

The deaths were “some of the worst cases we have seen,” Tracy Dunn, who oversees law enforcement for the southeast division of NOAA, said Wednesday. “It’s very difficult to solve without the community coming forward.”

Officials are offering a reward of up to $20,000 for information that leads to a civil penalty or criminal conviction in the cases. People can face up to $100,000 in fines and up to one year in jail per violation of the Marine Mammal Protection Act, which bans harassing, hunting, killing or feeding wild dolphins.

Biologists believe the recent deaths were the result of humans feeding the animals, which can learn to drop their guard around people. And at times, fishermen have been blamed for killing the animals in retaliation for taking their catch.

“When dolphins are fed, their behavior changes. They lose their natural wariness of people and boats,” said Stacey Horstman, a bottlenose dolphin conservation coordinator at NOAA. “The best advice is not to feed them, not to reach out to them. The seemingly innocent act of feeding dolphins can lead to harm and something like this.”

Horstman added, “This area of southwest Florida and in the panhandle are hot spots for illegal dolphin feedings.”

Since 2002, at least 29 dolphins, including the recent two, have been stranded in the southeastern United States after they were shot by guns or arrows, or impaled with objects like screwdrivers and fishing spears. A Kansas man was recently fined $1,250 for feeding a dolphin while he was vacationing near Florida’s Captiva Island, NOAA said, but many cases remain unresolved.

In May 2019, for example, a bottlenose dolphin that was impaled by a spearlike object in its head was found dead off Captiva Island. And in July 2018, veterinarians found a bullet in the lung of a pregnant bottlenose dolphin that had washed up on a beach in Mississippi. Animal welfare and conservation advocates offered a $11,500 reward to help solve the case, but it also remains unsolved.

Bottlenose dolphins are not considered endangered or threatened in the United States, but they often live close to shore and are at risk of coastal development, environmental degradation and being caught in nets. More than 1,200 dolphins washed up on France’s Atlantic coast last year, for instance, many with wounds suggesting that they died after becoming entangled in fishing nets.