Some of the surveillance role is going to be transferred to UAVs. Don't need all ATRs converted for increased coverage since we are also developing Sea Sultans along with drone fleet. Even US plans similar approach, P-3C has MAD (magnetic anomaly detector) boom in tail the P-8 doesnt. Flying low to use the MAD causes stress on the airframe because of turbulence as well as takes a toll on the crew. Which is why US plans a P-8+Drone combo with their drones still in R&D phase.
Turkish ATRs have MAD booms but PN ASW ATRs don't, its a capability we have on the P-3Cs but didnt include in our ATR ASW conversions suggesting PN looking might be looking into transferring this role to drones as well.