Marine Systems, Food Security, and Future Earth

Seafood, wild caught and farmed, has been a staple of
human diets for millennia. Dietary (isotope) and archaeological
evidence indicates fish were a significant part
of the diet of people in Africa and Eurasia in the Mid-
Palaeolithic (Hu et al., 2009), with the earliest South
African middens more than 150,000 years old. Tunas
and other such pelagic fish have been exploited for at
least forty-two thousand years (O’Connor et al., 2011)
and fish hooks carved from Trochus shell have been
found from Timor to Okinawa, indicating the widespread
use of such fishing gear by 23000 BP (Fujita
et al., 2016). Written evidence of the importance of
seafood to humanity dates to 4000 BC in Egypt (Chimits,
1957), with examples of texts on fishing methods
and management found in all major ancient human
cultures (Radcliffe, 1921; Costa-Pierce 2002). This love
of seafood has not dwindled through time and today the
total annual global fish production stands at more than
167 million tonnes of fish, with 146.3 million tonnes for
human consumption and more than half of that from
aquaculture (FAO, 2016). It is a major source of dietary
protein, with more than 3 billion people dependent
upon it. Fish has been the major source of animal
protein for human consumption since 1960 and this
per capita consumption is growing globally, trebling in
the last fifty years (Bene et al., 2015). The affluent
industrialised nations now consume at least 26.8 kg
per capita annually; consumption is slightly lower in
developing nations (at 20 kg per capita annually) and
even the citizens of the poorest and food-deficit nations
have doubled their consumption of seafood over the last
thirty years, now consuming 7.6 kg per capita annually
(FAO, 2016). This growth in consumption has
outpaced that of all other livestock sectors (including
chicken, pork and beef ) (Bene et al., 2015). Challenges
to land-based production such as shortages of water for
irrigation (Elliot et al., 2014), global warming and loss
of fertile soils (Rosenzweig et al., 2014) will all potentially
increase the role of seafood in food security.
The dependence of humanity on seafood goes far
beyond simple protein consumption. Fish have a reputation
as a source of long-chain n-3 (or omega-3) polyunsaturated
fatty acids, but they are also a crucial source
of readily accessible (bioavailable) micronutrients – such
as selenium, zinc, iron, calcium, iodine and vitamins A,
B and D (FAO, 2016; Golden et al., 2016). A reduction
in the availability of seafood could see 19% of the global
population at risk of increased perinatal, child and
maternal mortality; growth and cognitive retardation;
reduced immune function and other conditions associated
with malnutrition (Golden et al., 2016). Many of
these countries are situated in equatorial South East
Asia, Africa and Latin America. There is little capacity
to look to other food sources in these countries, as
poverty means they have a limited capacity to switch
to alternative dietary sources. A livelihood feedback
effect entrenches this dependence as the same countries
also have a heavy reliance on fisheries as sources of
employment and are economically sensitive to shifts in
seafood production (Allison et al., 2009).