North Atlantic fisheries, then and now

Scientists at UBC used ecosystem models, underwater terrain maps, fish catch records, and statistical analysis to estimate the biomass of Atlantic fish [large PDF] at various points the last century.  David McCandless of the UK Guardian’s Data Blog turned the resulting maps into this animated GIF:

McCandless writes:

These early accounts and data on the past abundance of fish help reveal the magnitude of today’s fish stock declines which are otherwise abstract or invisible.

They also help counter the phenomenon of “shifting environment baselines”. This is when each generation views the environment they remember from their youth as “natural” and normal. Today that means our fishing policies and environmental activism is geared to restoring the oceans to the state we remember they were. That’s considered the environmental baseline.

The problem is, the sea was already heavily exploited when we were young.

So this is a kind of collective social amnesia that allows over-exploitation to creep up and increase decade-by-decade without anyone truly questioning it. Today’s fishing quotas and policies for example are attempting to reset fish stocks to the levels of ten or twenty years ago. But as you can see from the visualization, we were already plenty screwed back then.

Further reading:

• Hundred-year decline of North Atlantic predatory fishes, by Villy Christensen, Sylvie Guenette, Johanna J. Heymans, Carl J. Walters, Reginald Watson, Dirk Zeller, and Daniel Pauly, Fisheries Centre, University of British Columbia. [large PDF]
• The Unnatural History of the Sea, by York University Professor Callum Roberts (Amazon|Chapters|Google Books).