Therefore, bottom trawling is inherently unsustainable because it erodes the very habitat upon which fish extracted from it depend. Shrimp trawling is also unsustainable because the high levels of bycatch will inevitably decline over time as stocks collapse. The Marine Trophic Index, a tool developed at the Sea Around Us project is one way of gauging if fisheries are staying the same. Another one is probing old-timers for shifting baselines anecdotes.
As for what to do: there is always Eating Like a Pig!