It looks as if the makers of "Great White" have bitten off more than they can chew with their tale of another big shark terrorizing the Atlantic seaboard. Ed Montoro, president of Film Ventures International, said several months ago that his film's only similarities to "Jaws" were that, like its more famous predecessor, his shark "swims in the water, and . . . kills people." But Universal Studios disagreed, and this week a federal judge sided with Universal and granted a preliminary injunction against further showings of the film because of a "significant likelihood" that a jury would find the two films "substantially similar." "The similarity in the basic story lines, the major characters, the sequence of events and the interplay and development of the characters and the plot is substantial," said Judge David V. Kenyon, who also said that "Great White" captured the first film's "total concept and feel" (while they might agree that the concept's the same, most film critics would probably dispute Judge Kenyon's assessment that the new movie has anything of a "Jaws" feel; it was unanimously trashed by reviewers). The injunction should remain in force until the case goes to trial; in the meantime, the distributors' lawyers have sprung into action with some deft wordplay. "This is a definite case of overbite," said attorney Kenneth E. Kulzick, who also claimed, "any successful Western or space-war film attracts a lot of other minnows to the same waters."