Oceans2012, a coalition lobbying to ensure that the 2012 reform of the European Union Common Fisheries Policy “stops overfishing, ends destructive fishing practices and delivers fair and equitable use of healthy fish stocks,” has produced a slick video to back up its campaign:
Typically, shrimp trawlers throw 80 to 90 percent of the marine creatures caught back overboard. This means that for one kilo of shrimp, up to nine kilos of other marine wildlife is caught and wasted….
Many of the farmed fish are carnivorous. That is, they eat other smaller fish. Five kilos of captured wild fish are needed to produce one kilo of farm-reared salmon. Aquaculture just converts low value small fish into higher value bigger ones. It does not create more fish
And this one, which I paraphrase:
In 2008, scientists recommended a catch limit for blue fin tuna: 10,000 tons.
Fishing nations set the limit three times higher: 29,500 tons.
Fishermen actually caught six times as much: 61,000 tons.
As is often the case with environmental pieces, the warnings are clear and persuasive, the practical solutions conspicuously absent.
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:
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.
It matters which farmed fish you’re eating, as some species consume more than others. Salmon is the worst, as this table, from a paper by Albert G.J. Tacon and Marc Metian of the University of Hawaii, demonstrates:
The red arcs represent wild fish inputs, the yellow arcs farmed fish output. The numbers inside the circles show the ratio between the two. Numbers greater than one mean more wild fish is consumed than farmed fish produced. Upchurch provides additional fine print.