As superfluous sequels go, "Jaws 2" appears to be a survivor. While it lacks the originality, wit and character interplay that gave "Jaws" an exceptionally appealing impact, "Jaws 2" is proficient enough to avoid bombing out. Unlike the sequels to "The Exorcist" or "The Omen," for example, this successor is neither a pretentious botch nor sluggish rehash.

Not that it isn't a rehash at bottom. Opening today at six area theaters, "Jaws 2" follows the plot of the original movie as if it were a little fish trailing in the wake of a big fish. The story blueprint is identical, although certain rooms and fixtures have been rearranged, typicall with less skill and justication than the master builder of "Jaws," the brilliant young director Steven Spielberg, displayed. While not a classic or a freash departure, "Jaws 2" pays compulsive homage and left-handed compliments to its classic prototype.

A Great White Spark suddenly looms off Amity, an oceanside resort community, and spreads terror along the beaches. We've passed this way before, three summers ago, when "Jaws" became a runaway box-office sensation. There are moments when you begin to wonder if Amity is as timeless as Brigadoon.

Convinced of the shark peril, Police Chief Martin Brody, again played by Roy Scheider, sounds the alarm to Mayor Larry Vaughn, again played by Murray Hamilton. The mayor's ignoring the threat frustrates the chief who is manipulated by melodramatic circumstances into a mano a mano, so to speak, with the monster from the deep. The "new" wrinkles are a transformation of the chief's character and a shameless exploitation of kids, who are the climatic targets of the beast's assaults. Neither wrinkle qualifies as a clever enhancement.

The filmmakers' anxiety about the reactions of their vast potential public surfaces constantly. THe most annoying is the excessive use of shots in which teen-age actresses scream into the cinema, go numb with terror or stammer."Sh-sh-sharrrrrrrrrr-KKKKKKKK."

The image of paralyzed or shrieking teenyboppers is one of the major motifs of the film, along with seagoing angles that keep anticipating shark sightings in the background and heroic profiles of Scheider, who strikes O'er-the-Ramparts-I-Watch poses against the horizon. Spielberg never stopped to such blatant nudging of the audience. The voluntary responses by the audience in "Jaws" are now anticipated and incorporated in "Jaws" in order to whip up excitement.

The reliance of director Jeannot Szware on "Screaming Mimi inserts" is the most obvious example of how the filmmakers' calculations have coarsened. The exploitation of cardboard teen-age characters is another indication. They reflect more demographic concerns than storytelling. All the kids out ther are supposed to identify with the kids up there, but these surrogates never evolve into interesting characters.

One young actor does stand out: Gary Springer as Andy, the stocky, curly-haired pal of Mike, the eldest of Brody's sons. Springer demonstrates force and urgency when he overcomes the fear felt by Sean, the youngest Brody boy, during the climactic shark attacks. It's one of the few genuinely tense and stirring human interludes in the picture, a spontaneous heroic gesture.

Derivative of plot and expedient of characterization, "Jaws 2" places a heavy burden on the role of Brody. Indeed, it violates the attractive, common-man psychology of the original character as originally embodied by Scheider. Forced to go it alone as a sharkhunter, Brody ceases to function as the scared average family man and degenerates into the crazed avenger, i.e., the behavioral and moral equivalent of the late Capt. Quint. Unfortunately Scheider's action resembles Kirk Douglas' under stress, a resemblance he would be wise to avoid for the rest of his career.

In contriving a sequel to "Jaws" the filmmakers haven't demonstrated a coherent notion of how to revive and explort the emotions and apprehensions generated three years ago. Their calculations produce contraditions. While our experience of the original threat is supposed to heighten the renewed threat, we're also expected to forgive the filmmakers for attacks of amnesia.

How can you help but giggle when Hamilton's face falls and he warns Scheider, "Martin, don't press it this time." Evidently, the earlier episode has not made authorities any more shark-conscious. Why not? Isn't the audience itself supposed to be constantly aware of the dangers posed by a shark assault?

After the chief's outbursts lose him his job, we see a trophy in his office naming Brody Amity's Man of the Year in 1975. There's no reason to doublt the existence of the first shark now that a second one has appeared. Even if the towns people were given a reason to question Brody's concern, how could the audience play along?

It's simply a matter of convenience. The filmmakers find it convenient for the mayor to act as stubborn as before. At the same time they find it equally convenient for Brody to begin acting bughouse on the subject of sharks, eventually challenging the shark to come out of the water and get what's coming to it.

Perhaps the erosion of humane considerations between "Jaws" and "Jaws 2" will be imperceptible or immaterial to some of the audience. It's possible that in the last resort the extra dimensions that distinguished "Jaws" - Spielberg's marvelous juxtaposition of terrifying and funny stimuli and the sense of comradeship between the disparate personalities were not essential to its mass appeal. Did the humor and subtlety of the original enchance the terror for only a minority of the audience?

If so, it probably won't matter to a significant number of customers when the manipulation becomes obvious. They may even prefer it. Nevertheless, it betrays a decline in sophistication to fall back on blatant manipulative cues.

There are no new thrills to speak of, but Szwarc stages two or three effective thrill sequences recombining perilous situations from "Jaws." The streamlined proficiency of the original is lost, in part because one shark is now required to chew up too many vessels going in too many directions. In fact, the shark demonstrates such an appetite for chewing property that he may be considered more of a threat to pleasure craft than life and limb.

Nevertheless, Szwarc delivers the chills and jolts in make-or-break moments. His neatest sequence is a watery cliffhanger in which two kids struggle to drag a friend aboard as the shark comes skimming along the side of their boat, jaws agape.

"Jaws 2" is, of course, a presumptuous attempt to repeat the unrepeatable. While it gets by, it remains to be seen if it can duplicate the popularity of the original. "Jaws 2" isn't a disgraceful self-imitation, but one sampling should be enough. It may inspire nothing so much as a nostalgic hunger to see "Jaws" again.