This is a foul play of so called "environmentalists." They want dollors for their livelihood, and making these cries.
As such these days, fishermen are netting only the arms and ammunitions floating across the palk straight.
When such an amount of explosives are used in fighting, and huge amount of poisonous war related materials are used in this waters, none of this people made a voice.
In my opinion, once this canal is opened up, there will be heightened security along the indian coasts, that will avoid indian fisherman being shot, or arrested.
Even three days ago, 10 fishermen were arrested along with the boats by the Srilankan Navy - while, India says it has increased the security in this region!
Do not worry about fishes, and corals. They are not affected, and they will survive at any conditions - once there is water!