Environmental Engineering Reference
In-Depth Information
ity were made possible by the seasonal abundance of fatty salmons (cod's energy
density is just 3.2 MJ/kg, Chinook salmon rates 9.1 MJ/kg) and their preservation
by smoking.
But no species was more rewarding to hunt than bowhead whale, one of the
world's most massive mammals: even the immature two-year-old animals that were
most commonly killed by the Inuit hunters using boats and spears weighed nearly
12 t. Moreover, their tissues had an extraordinary food energy density: at about 36
MJ/kg their blubber, and at 22 MJ/kg their
mukluk
(skin and blubber), were at least
twice and up to three times fatter than the fattiest i sh, and the tissue could be easily
preserved in permafrost dugouts. Sheehan (1985) calculated that the coastal settle-
ments would enjoy food surplus even when assuming a minimum baleen whale
harvest near the shore during three to four months of seasonal migration together
with a subsidiary i shing and killing of beluga whales, walruses, and seals.
Fishing did not lose its importance with the emergence of ancient complex civi-
lizations but its impact remained spatially circumscribed, coni ned for millennia to
the most heavily exploited coastal waters. Localized overi shing of some preferred
species certainly took place in some coastal areas of the Mediterranean during
Roman times, but many medieval references to an astonishing abundance of i sh
attest to the presence of large stocks of herring, mackerel, cod, salmon, pilchards,
and sprat. Although there were some temporary reductions as a result of local
overi shing or changing water temperature, abundant i sh stocks in Europe's Atlantic
waters lasted well into the nineteenth century (Roberts 2007). At the very beginning
of the modern era, Europeans also discovered i sh stocks that became the focus of
the world's i rst long-distance i shery that, remarkably, lasted for nearly i ve subse-
quent centuries.
This could happen only after suitable ships became available, and it is not at all
surprising that Spanish and Portuguese sailors, the pioneers of the European voyages
to Africa, the Americas, and Asia, were also the i rst practitioners of i shing far from
home ports. The Grand Banks of Newfoundland, where the sea appeared to swarm
with cod, were discovered by a British expedition (John Cabot in 1496), but Por-
tuguese, Basque, and French ships had opened up the i shery by 1517. Two centuries
later the banks were visited annually by hundreds of European ships, but abundant
cod stocks were present even during the second half of the twentieth century.
Only then, after decades of overi shing by Western European, Russian, and Japa-
nese l eets outside Canadian waters and by excessive numbers of Canadian vessels,
did that great ancient i shery (and tens of thousands of associated jobs) collapse
(Bavington 2010). In 1992, the Canadian government imposed a moratorium on
