In a certain aquatic biome, the fish and turtles feed on sea grasses. recently, the availability of sea grasses in that aquatic biome is diminishing. hence, there is severe competition among the turtles and fish for food. what type of competition exists between these two species?

The type of competition that exist between the two species is INTERSPECIFIC COMPETITION.
There are basically two types of competition in any given ecosystem, these are intraspecific and interspecific competition. Intraspecific competition occurs among organisms of the same species while interspecific competition occurs among organisms of different species.

Probably a behavioral adaptation