FREMONT ISLAND, Utah (AP) _ Forty wild Welsh ponies were shot dead and left to rot on this Great Salt Lake island because the rancher who rents the island said he could not afford to capture and move them.

The carcasses were discovered Saturday by a private pilot on a recreational flight, said Antelope State Park Superintendent Mitch Larsson, who had gone to the island Monday, concerned the animals may have died from disease.

The uninhabited island was leased to rancher Dallen Ward last fall, and Ward killed the horses to make way for sheep he plans to move from his home in Almo, Idaho, said Weber County Sheriff's Lt. Archie Smith.

Ward said Monday that the horses were over-grazing the island, and the cost of moving them was prohibitive.

''We looked at every avenue possible and economically I couldn't do it,'' he said, explaining he would have had to hire a crew to round up the horses and rent a barge to move them.

He also said he could find no buyers for the animals.

Ward said he shot the animals himself, but he refused to discuss details.

Bruce Dibb, an attorney for the owner of the island, Steven Richards Sr., said the horses were introduced about 30 years ago with commercial recreation in mind. However, the enterprise never got off the ground and the horses became wild.

Dibb said his client removed about 100 horses by barge last year, but the others eluded capture.

The shootings probably did not violate Utah law, said John Fox, a special deputy for the Utah Humane Society. ''Unless it can be proved the horses suffered or didn't pass out right away, it is legal,'' he said.

However, Fox said Ward may have violated the law by not burying the horses within 48 hours, a misdemeanor.

Smith said he planned to speak to Weber County Attorney Reed Richards to determine whether charges should be filed.

The ponies appeared to have been dead for about two weeks, said Utah Veterinarian Michael Marshall, who accompanied Larsson to the island Monday.

''There is no real danger from the carcasses other than maybe a bird pecking on them, then flying across to the mainland with that material,'' Marshall said. ''But I don't see any way to bury them. You would have to airlift a backhoe over there to do it.''