Most of the high seas catch from deeper waters is carried out by bottom trawling which involves dragging massive nets along the sea bed – a practice which can destroy deep-sea corals and sponge beds that have taken centuries or millennia to grow. SourceThis practice, environmentally disastrous as it is, is profitable only because of subsidies; half of which are fuel subsidies. From the same article:
“The unregulated catches by these roving bandits are utterly unsustainable. With globalised markets, the economic drivers of over-fishing are physically removed and so fishermen have no stake in the natural systems they affect. While it may be a good short-term business practice to fish out stocks and move on, we now see global declines of targeted species.”The major villains in this particular madness are South Korea, Japan and Russia, but most rich countries continue to subsidise insanely destructive practices in agriculture, transport and energy.