Does anybody know if this is a fact? It is in an article in the Arab Times, reporting on a UNEP report. I've heard that a third of the world's protein comes from the oceans. But these huge numbers seem to get tossed around a lot.
I remember reading in a 2003 Marine Biology book that 19% of the worlds’ protein comes from fish/seafood. Right away, this statistic that half of the world depends on the ocean as a food source seems a little bit off.
As it turns out, half of all PRIMARY PRODUCTION comes from the sea. Not half off all HUMAN food PRODUCTION.
Primary producers (ex: algae, bacteria) are at the lowest level of the food chain. Primary producers use sunlight--photosynthesis—(or chemicals--chemosynthesis) as a source of energy and are important for ALL life in the oceans. This can account for 50-70% of all photosynthetic activity in the ocean. (Herein the confusion lies)
It is critical to understand the tropic levels within a food chain. One simple food chain is as follows:
Killer Whales (top carnivore)
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Seals
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Penguins
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Squid
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Krill (Primary consumers)
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Diatoms (Primary producers)
Without primary producers, the upper levels of the food chain would collapse.