I'm from Greece. I've heard numerous stories from the victims themselves, the ones that managed to survive. This is all true and just the tip of the iceberg.
It happens to the Evros river as well where people from Turkey come from.
There was a shipwreck in Pylos with hundreds drowned last year.
And there are many cases from people that are rescued that later are returned or tortured.
The ones that manage to get a staying permit as official refugees, are treated by most government offices with inequality and lies.