The Little Ice Age: How Climate Made History 1300-1850 (15 page)

Cod are highly temperature sensitive and poorly suited to extremely cold
water. Their kidneys do not function well below about 2°C, but the fish
thrive in water between 2 and 13°C. Temperatures between 4 and TC are
optimal for reproduction. Greenland is a telling indicator of how cod populations move with changing water temperatures. For much of the past five cool
centuries, the waters of Greenland were too cold for large cod populations except in the most sheltered areas. After 1917, the warmer Irminger current,
which flows south of Iceland, extended around Greenland's southern tip.
Cod eggs and larvae from spawning grounds north and west of Iceland were
carried across the Denmark Strait and around the southern tip of Greenland
by the West Greenland Current. By 1933, water temperatures were high
enough for cod to thrive up to 72° north. By 1950, cod still abounded as far
north as Disko Bay, at 70° north. During the past four decades, the water has
turned much colder and Greenland cod stocks have plummeted.8

Similar movements of water masses and the resulting changes in sea
temperatures affected cod populations in past centuries. We can sometimes track the effects in fisheries records. During the bitterly cold seventeenth century, northern sea temperatures fell below the critical 2'C level
along the Norwegian coast and far southward for periods of twenty to
thirty years. The Faeroes cod fisheries failed totally in 1625 and 1629.
There were no cod after 1675 for many years. By 1695, they were sparse
even as far south as the Shetland Islands. The scarcity pertained for most
of the time between about 1600 and 1830, during the coldest episodes of
the Little Ice Age. Similar shifts in cod populations undoubtedly occurred in earlier centuries, especially during the cooling of the thirteenth century just when the demand for dried and salted cod was exploding. Had
we the historical records, the changing distribution of cod in the far north
would be a remarkable barometer of rising and falling sea temperatures.
As it is, there is a strong connection between deteriorating climatic conditions, new designs of oceangoing fishing vessels, and an inexorable spread
of cod fishing away from the European continental shelf onto another
shelf, off virtually unknown lands far to the west.

During medieval times, the Basques of northern Spain, who controlled
abundant salt deposits, acquired a sterling reputation as whale hunters.9
They sold fresh and salted whale meat as "cold" flesh for holy days as far
afield as London and Paris. By the ninth century they were skirmishing
with the Norse in the Bay of Biscay and had begun to copy their adversaries' clinker-built ships, with overlapping planks fastened with iron rivets. The Norse, Europe's consummate long-distance voyagers, used dried
cod as hardtack at sea as well as to sustain themselves during the winter
months. Long before Eirik the Red sailed to Greenland, the Norse
processed large quantities of cod and traded the surplus far and wide. The
Lofoten islands in northern Norway were a major source of dried cod in
the north as early as the twelfth century. The cold, dry winds and sunny
conditions of early spring were ideal for desiccating split fish carcasses.

Atlantic cod are unknown off northern Spain but were common in the
northern summer whaling grounds of Norway and the North Sea that became accessible to new generations of Basque fisherfolk once they began
building Norse-style boats in the twelfth century. They pursued cod from
the same small open dories they used to stalk whales, and applied the
same salting methods as well. Like the Norse, they lived off cod hardtack
at sea, sailing as far north as Norway, the Hebrides, even Iceland. By the
fourteenth century, salted and dried Basque cod, bacalao in Spanish, was
known throughout Spain and the Mediterranean. The Basques prospered
off cod and boatbuilding. Their large, beamy ships with their exceptional
hold capacity were in demand throughout Europe.

In the mid-fourteenth century, as ice conditions in the north became
more severe and water temperatures fell, the cod stocks off Norway began to falter. Iceland had become increasingly isolated. The great days
of Norse voyaging were over, and the islanders, living in a timberless
land, showed little inclination to become seamen. They continued to
fish for cod from small open boats close inshore-a tradition that
would continue until the nineteenth century-while others reaped a
rich fish harvest offshore. Year after year, no Norwegian ships arrived,
nor vessels from elsewhere, except when a shipload of Scots was
wrecked and "none understood their language."10 Norway's close monopoly over trade with its dependency, maintained for generations,
withered in the face of competition from the ever more aggressive
Hanseatic League, based on the Baltic. The League was a powerful
commercial association of member cities based in Lubeck in Germany,
which reached the height of its power in the fourteenth century. The
Hansa was a mercantile organization with significant political clout,
which levied taxes to suppress piracy and inevitably became involved in
the politics of established kingdoms. Its members dominated trade over
northern Europe until the fifteenth century, when aggressive modern
states provided overwhelming competition. For a time, the League effectively controlled Denmark's monarchy.

Iceland was "the desert in the ocean," increasingly isolated, her population decimated by the Black Death and increasingly severe winters. When
Norway and Sweden were united with much more powerful Denmark in
1397, Iceland found itself at the mercy of a more distant, rapacious master who laid even heavier taxes on the island. The angry Icelanders were
ready to ignore Norway's monopoly and welcome any foreign ships that
arrived at their shores.

For generations, English fishermen and merchants had sought cod in
Norwegian waters. The trade prospered despite a requirement that all
catches had to be brought into the port of Bergen for taxation before export. The tax was little more than a nuisance until a cabal of Hansa merchants who controlled Bergen effectively closed Norwegian fisheries to foreigners in 1410. The prohibition may have been prompted by falling cod
stocks off Norway due to colder water conditions. For English fishing communities, the only chance for good catches now lay in an increasingly
stormy North Sea and much further afield in Iceland's cold, remote waters, where cod were known to abound. English fishing fleets would have to sail
far offshore in the depths of winter to bring salt cod to market in time for
the autumn sales. The ships of the day were ill equipped for such voyaging.

The prudent medieval mariner avoided going to sea in winter. Thirteenth-century Scandinavians with their open boats stayed ashore from
November to March. According to an early English poem, The Seafarer,
Anglo-Saxons did not venture onto the open ocean until after the first
cuckoo of early summer. They were wise, for severe gales are eight times
more frequent in these waters during winter than in summer, with rough
seas at least every fourth winter day, perhaps even more often during low
cycles of the NAO. A higher frequency of gale-force winds and high seas
between May and September, after centuries of kinder weather, would
have wreaked havoc with fishing fleets and the heavy merchant vessels
that plied these waters. Even into the twentieth century, decked, engineless fishing boats stayed in port if the wind blew above 30 knots (about
35 miles per hour). The undecked vessels of earlier times would not have
left harbor in a strong breeze of more than 20 to 25 knots.

Even in favorable weather, medieval seafaring under oar and sail required a more intimate knowledge of ocean and weather than is possessed
by almost anyone today. Patience and experience compensated for many
deficiencies in ship design. Wise seamen, knowing the perils of sudden
storms and strong headwinds, might wait at anchor for weeks on end for
favorable winds. Even with more efficient rigs and infinitely more seaworthy ships, the rhythms of life under sail endured into this century. During
the 1930s, the English yachtsman Maurice Griffiths frequently shared anchorages in eastern England river estuaries with fleets of Thames barges
awaiting a northerly wind to head south to London. One memorable
September dawn, after a long, stormy night in the sheltered Orwell River,
he woke to the sound of clanking windlasses as dozens of waiting barges
raised sail to an unexpected northwesterly wind. Within minutes, brown
spritsails crowded the river in a long line down to the North Sea. Some of
the barges had been in the anchorage for a week, waiting out the strong
headwinds.

The Thames barge has a relatively efficient rig, ideal for easy handling
in narrow creeks and shallow channels. Medieval cargo ships were not in
the same league. They flew square sails before the wind and used oars to
go to windward. Heavy cogs and hulcs carried bulk cargoes between
Hanseatic ports in the Baltic and linked British ports to the Continent.
Solidly built to carry heavy loads, mostly in shallow waters, they labored
when faced with gale-force winds and high Atlantic swells. The clinkerbuilt Norse knarrs and long ships were more seaworthy but were not intended for winter voyaging or fishing. The stormier seas of the thirteenth
and fourteenth centuries, and the need to range far offshore each winter
in search of cod, demanded more seaworthy craft.

As so often happens, new economic realities brought striking innovations in ship design. Herring abounded in the southern North Sea, but the
fishermen could only stay at sea a short time until the Dutch invented the
buss, a much larger ship that combined fishing with the gutting and salting
of the catch on board. These remarkable vessels transformed the herring
fishery into big business. By the mid-sixteenth century, as many as four
hundred busses operated out of Dutch ports, each carrying from eighteen
to thirty men who remained at sea for between five and eight weeks at a
time.11 Strict regulations controlled the quality of the product, with the
ships often traveling in convoy to minimize the risk of piracy. For centuries, English merchants and fisherfolk had used open boats and larger
decked vessels built in the Norse fashion-light and buoyant, but not designed to handle the large ocean swells and fierce winds of winter. These
boats were built shell first, then strengthened with frames. Most of their
strength, as a result, lay in their outer skin. Some enterprising boatbuilders
eyed ships built by the Dutch and the Basques, who had adopted the practice of erecting the skeleton of a boat's hull before planking it. These ships
proved much stronger, more durable, and easier to maintain. The new
methods led to the English "dogger," an oceangoing vessel with two or
three masts and high pointed bows that enabled it to breast steep head
seas. A low stern made a good platform for fishing with lines and nets.12

The dogger was originally a small boat used on the Dogger Bank in
the southern North Sea and for cod fishing. The rig had a square sail on
the main mast set well forward and a three-cornered lateen-style sail on
the after spar, enabling it to sail closer to the wind, an important consideration when sailing to and from Iceland in prevailing southwesterly winds. For the first time, fishermenTiad access to vessels that were strong
enough and seaworthy enough to sail almost anywhere. Simply constructed and easily repaired in the remotest convenient bay, the dogger
expanded the cod fishery far beyond the narrow confines of the North
Sea. Casualty rates at sea were enormous, but in an era of brief life expectancy and brutal conditions on the farm, people accepted the risk
without question. So many doggers and other fishing craft vanished at
sea that boatbuilders prospered at home, especially along the northern
Spanish coast, where entire Basque villages did nothing but build replacement fishing boats.