Misfits of Science (1985)

S1E6 Sonar...And Yet So Far

Billy's friend, a marine biologist devoted to studying dolphins, is convinced that these creatures can communicate. His theory draws the attention of drug traffickers who seek to utilize the dolphins' assistance in locating a submerged stash of cocaine. As the biologist finds himself entangled in their dangerous plans, he must rely on his aquatic allies to navigate the perilous waters and thwart the smugglers' scheme.