When Does "JAWS 2" (1978) Take Place?
"JAWS 2" is a horror film written by Carl Gottlieb with Howard Sackler that released June 16th, 1978. So when is "JAWS 2" set?
It takes place in the year:
We know this because about one-tenth into the movie the audience sees that Police Chief Martin C. Brody has an award in his office that is only visible for a second (but is seen more clearly almost halfway through) which reads "MARTIN C. BRODY" and "AMITY MAN OF THE YEAR 1975". So it must be during or after 1975 AD.

1978 AD
We know this because about one-tenth into the movie the audience sees that Police Chief Martin C. Brody has an award in his office that is only visible for a second (but is seen more clearly almost halfway through) which reads "MARTIN C. BRODY" and "AMITY MAN OF THE YEAR 1975". So it must be during or after 1975 AD.
More specifically, Brody says, "4 years down the drain." when he is replaced as police chief. In the previous film, "JAWS" (1975), which takes place in 1974 AD, Brody asks, "How come the Sun didn't used to shine right here?" and his wife Elaine Brody responds, "We bought the house in the fall and this is summer." So they were in their first year on Amity Island and he was in his first year on the job in 1973 AD through 1974 AD.
1974 + 4 = 1978.
It was loosely adapted to prose (novelization) in early 1978 and loosely adapted to comics in late 1978 as "Marvel Super Special" #6. (Both of these works adapt an early unused version of the script by Dorothy Tristan with Howard Sackler and, therefore, the final products should be treated like original works.)