This type of communication, called intraspecific communication, includes communication associated with finding appropriate mates (called courtship) and competing for resources such as food or habitat.
The photophores are thought to play a role in attracting the zooplankton upon which the fish feed; intraspecific communication may also be a use for the light.
It suggests that acoustic signals in the environment should display frequency partitioning as a result of selection acting to maximize the effectiveness of intraspecific communication for different species.