The small yellow plane that drops the canister to the diver is the same Ryan Navion used in Pilot Error (1974).
In "Sharks: Part 1" (1977) Steve Austin (Lee Majors) is aboard a nuclear submarine USS Stingray (SSN-501). "SSN 501" can be seen in a stock footage external shot of the submarine under water. Though fictional for this period in time, the last real USS Stingray was decommissioned following WWII. This same submarine was used previously in the Bionic Woman "Kill Oscar: Part III" (1976) - A shot while Jaime and Steve are on the submarine has a plaque showing that the boat it is "SSN 501". If Steve Austin were to be on any submarine, it would only be appropriate that it were a nuclear submarine, seeing as how the show title's Spanish translation is "El Hombre Nuclear."
The same basic plot (a sabotaged underwater transceiver device, and sharks being attracted by artificial means to interfere with repair divers) is used in Deadly Music (1978).
With the summer success of The Deep (1977) keeping alive the public's interest in ocean adventures, The Six Million Dollar Man kicked off its fifth season with a two-parter episode about killer sharks. The episode had its own movie poster, suggesting that the two episodes had been combined as a feature and released on home video, screened theatrically, or played on cable/free to air television as a single entity. The movie poster for it doesn't mention The Six Million Dollar Man television series it was made for. It has a credit block typical of a feature film and runs with the tagline: ''You are gripped again by horrifying shark terror!''. (It was a common practice then to make these episodes into feature films to be shown in overseas markets.)
Cast from Star Trek. Look out for an unmistakable but very young Q as a diver in part 1. Also, be on the lookout for a very young Gul Dukat as Williams in part 1.