It seems that humanity's voracious appetite for fish — be it wild or farmed — is depleting the ocean so much of its smaller "prey fish" and krill that marine predators, such as dolphins, seals, whales, are facing starvation. A new report by ocean conservation group Oceana describes how "scrawny predators — dolphins, sea bass and even whales — have turned up on coastlines all over the world", including seabirds "emaciated from lack of food, vulnerable to disease and without enough energy to reproduce".
Oceana's "Hungry Oceans" report uses figures from the Food and Agriculture Organization (FAO) which found that since WWII, 88 species of small prey fish (a staple for larger marine animals and seabirds) have become major targets for seven of the 10 top fishing fleets. As predator fish populations such as tuna and salmon are now being overexploited to the brink, four times as much of these little fish are now brought in, compared to fifty years ago.
Fish caught to feed fish, not people
Instead of feeding people, four-fifths of this catch ends up in fish farms or in fish oil. Much like the vast amounts of water needed to produce one pound of beef, as opposed to the water needed for vegetables to directly feed someone - it takes 11 pounds of fish meal for one captive fish to gain 1 pound.
The report notes that part of the problem is lack of responsible, farsighted management, which arbitrarily assumes the amount of prey fish needed to sustain predator populations is low:
Prey fish are taken for granted in fisheries management, despite their critical role in marine food webs. Even in planning the recovery of endangered or overfished species, managers often give no consideration of the food supply needed for their populations to rebound. Squid, krill, and other prey remain ignored, unregulated and unaccounted for.
[..] For example, recent analysis found that marine mammals and large fish are actually eating four times as many herring than assumed by the official government assessment (Read and Brownstein 2003). In failing to account for these predators, the typical approach overestimates the amount of fishing that can be sustained by their prey. For years we have been catching many more prey fish than can sustain both human fisheries and predators.
"For years we have been fishing on a deficit"
The report names three major threats to the stability of prey fish populations and the marine food web in general: overfishing, aquaculture and climate change. The report also suggests some solutions, including:
- Manage for ecosystem integrity
- No new fisheries for prey species
- Set conservative catch limits
- Prioritize uses for prey after predator needs have been met
- Fish less during natural declines
- Maintain a reserve for natural predators
- Protect breeding hotspots
- Save 10% buffer of prey populations for climate losses
Faced with ocean acidification, coral reef die-offs, dead zones, the doubtful shadow of oceanic geoengineering, the Great Pacific Garbage Patch, piracy caused by overfishing, chemical and sonic pollution — and now the starvation of larger marine animals - isn't it time to do the oceans a favour by eating less fish or not at all?
Oceana (full PDF report) via The Independent
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