Geoscience Reference
In-Depth Information
But where these two great currents meet and mingle off Cape Race on the southeastern tip of Newfound-
land, a great profusion of marine life is kick-started on the Grand Banks. The Labrador Current is rich in nutri-
ents and carries the plankton that are the base of the banks' grandness. The waters of southeastern Newfound-
land have four to five times the biomass of zooplankton of the warmer waters of the Gulf Stream, which never-
theless adds heat, boosting their productive capacity. The productivity of these Newfoundland waters is spec-
tacularly expressed not only in fish but also in the seabirds and marine mammals that gather here in phenom-
enal numbers.
“Fish” by No Other Name
The continental shelf off southeastern Newfoundland is one of the largest in the world—a vast apron larger
than the island of Newfoundland itself. This is the legendary Grand Banks, where the two major currents of the
northwest Atlantic converge, stirring nutrients into the water column. The shallowness of the banks, which
range in depth from 25 to 100 meters (80 to 300 feet), combined with their great extent, underlies one of the
most productive ecosystems on the planet. As fisheries scientist George A. Rose has written in Cod: The Eco-
logical History of the North Atlantic Fisheries, “these ecosystems produced an abundance of life the likes of
which the world has seldom seen.” The great quantities of cod were the draw for most early European excur-
sions to North America. The Grand Banks' capacity as a natural fish-producing factory was probably un-
matched in history, as illustrated by the account of John Cabot, who, in 1497, reported the waters “swarming
with fish, which can be taken not only with the net, but in baskets let down with a stone.”
In the Newfoundland idiom, “fish” has only one meaning, codfish, suggesting the historic importance of cod
to the culture of Newfoundland and the central role it has played in the ecosystem of the northwest Atlantic.
Atlantic cod is a generalist and has adapted to many niches in the North Atlantic, where it is a dominant
predator on both sides of the northern ocean. Cod are survivors. Part of their durability as a species is their om-
nivorous appetite. They will eat almost anything, including smaller cod. But their preferred prey is the smelt-
like capelin, and wherever capelin have gone, cod have followed. Before capelin emigrated from the Pacific, it
is likely that cod populations subsisted on herring, which remains an important alternative prey. But the ability
of cod to grow into the huge populations depended on the arrival of capelin, which, like herring, is a fat-rich
species and therefore an important source of calories in the cold environment of the North Atlantic.
Given cod's economic importance, it is surprising how little was known about its reproductive behavior un-
til quite recently. Cod tend to form large aggregations in the winter, lying near the ocean bottom in a kind of
torpor, at incredible densities of more than one fish per cubic meter (1.3 cubic yards) of water. As spring and
spawning season approach, they become more active and form new aggregations, with males and females of
similar sizes seeking each other out.
