TRENTON (New Jersey) - THE survivors of a group of dolphins living in a New Jersey river have returned after briefly heading toward the sea.

Three of the five dolphins returned to the Shrewsbury River after they were spotted on Saturday in Sandy Hook Bay, authorities said. They were apparently frightened by construction noise near the bay, the Marine Mammal Stranding Centre said.

Four dolphins tried to cross again on Sunday but turned back, although it wasn't clear why, the centre said.

Three dolphins had been confirmed dead out of the original group of 16 that spent the summer and fall in the Shrewsbury and Navesink rivers.

Authorities do not know what happened to the others.

Animal rescuers are fighting with federal wildlife officials over whether to remove the dolphins. -- AP