How Our Seas are Changing,
by Callum Roberts,
Reviewed: 19 September
I was reading this book while the Australian government was deciding whether to give a trawling licence to one of the world's largest floating fish factories. The ships owners have headed for Australian waters after exhausting, and being expelled from, other fishing zones off Africa and in the South Pacific.
Callum Roberts is a professional ocean conservationist. The fishing industry lobbyists and libertarian economists would therefore dismiss his arguments as biased. No doubt the same arguments were made by denialists as earlier human societies in the middle east and in Central America, and Southeast Asia devastated the environments on which their advanced civilisations depended.
The deafening political noise around atmospheric carbon emissions can distract us from the even more critical state of our planet’s oceans. The plight of the seas is not about the extinction of photogenic clown-fish or pretty pink corals – it is about threats to the very engines of life as evolved on this planet. Earth only acquired its oxygen-rich atmosphere in the latest ten percent of its history, and it was ocean-dwelling bacteria that generated the oxygen in quantities that enabled the evolution of land-based plants and animals, ourselves included.
The oceans are still the primary forces that drive earth’s atmosphere and the climate we experience from it. The web of micro-organisms that condition the water, oxygenate the atmosphere, and feed the next level of life, is becoming unbalanced with potentially dire consequences. Excess nutrients, flooding from our agriculture and aquaculture practices, create semi-desert monocultures where once biodiversity prevailed in the nurseries of oceanic life.
Roberts supports the harvesting of marine life for human consumption, but he castigates the stubborn way that humans persist in destroying that upon which our growing population depends. Since the development of steam-powered trawlers, we defy an elementary rule of capitalism, by consuming the capital resource rather than the income it generates. More and more mechanical power has been employed to harvest smaller and fewer fish. Without drastic restorative action, Roberts sees our strip-mined oceans reduced to supporting vast rafts of plastic rubbish and populated by little more than hordes of jellyfish and scavenging prawns. The evidence of recovery is overwhelming when marine reserves are properly implemented.