Page 440 - Environment: The Science Behind the Stories

Then came the crash. Catches dwindled in the 1980s stock yet again. Fishing continues in this limited area and
because too many fish had been harvested and because researchers and resource managers are monitoring popula-
bottom-trawling (fishing by dragging weighted nets across the tions closely to see how they fare over time.
seafloor, p. 457) had destroyed huge expanses of the cod’s Across the border in U.S. waters, cod stocks had col-
underwater habitat. By 1992 the situation was dire: Scien- lapsed in the Gulf of Maine and on Georges Bank. In 1994, the
tists reported that mature cod were at just 10% of their long- National Marine Fisheries Service (NMFS) closed three prime
term abundance. Canadian Fisheries Minister John Crosbie fishing areas on Georges Bank. Over the next several years,
announced a two-year ban on commercial cod fishing off NMFS designed a number of regulations, but these steps were
Labrador and Newfoundland, where the $700 million fishery too little, too late. A 2005 report revealed that the cod were not
supplied income to 16% of the province’s workforce. To com- recovering, and further restrictions were enacted. As of 2008,
pensate fishers, the government offered 10 weekly payments managers announced that the Gulf of Maine stock was 58% of
of $225, along with training for new job skills and incentives what it needed to be to be sustainable, and the Georges Bank
for early retirement. Over the next two years, 40,000 fishers stock was only 12% as large as it needed to be.
and processing-plant workers lost their jobs, and some coastal There is good news in the cod fishery, however. A 2011
communities faced economic ruin. study reported Grand Banks cod populations were at 34% of
Cod stocks did not rebound by 1994, so the government historical levels, after hovering at around 5% of historical lev-
extended the moratorium, enacted bans on all other major cod els for the previous 20 years. When cod were driven to low
fisheries, and scrambled to offer more compensation, eventu- numbers by overharvesting, populations of forage fish, such
ally spending over $4 billion. In 1997–1998, Canada partially as capelin, increased ninefold as a result of reduced cod pre-
reopened some fisheries, but data soon confirmed that the dation. These forage fish then preyed upon and outcompeted
stocks were not recovering. In 2003, the cod fisheries were young cod, slowing cod recovery. Populations of forage fish
closed indefinitely, to recreational fishing as well as commercial are now in decline, however, because they have outstripped
fishing. It became illegal for Canadians in these areas to catch their plankton food supply and are now themselves being har-
even one cod for their family’s dinner. Fishers challenging the vested by fishermen, giving cod the opportunity to rebound.
ban were arrested, fined, and jailed. The good news in the Georges Bank is not limited to cod,
Then in 2009, a portion of the Grand Banks off the south- though. Seafloor invertebrates have begun to recover in the
eastern coast of Newfoundland was reopened to cod fishing absence of trawling. Spawning stock of haddock and yellow-
after data showed the stock was recovering slightly. Some tail flounder has risen. Sea scallops have increased in biomass
dreamed of a comeback for the fishery, but others thought the 14-fold. Recoveries like these in no-fishing areas are showing
decision ill-advised. Allowable cod harvests were set beyond scientists, fishers, and policymakers that protecting areas of
what a scientific review board had recommended, and many ocean can help save dwindling marine populations and restore
feared another hasty reopening would simply decimate the fisheries.

The Oceans of water (Figure 16.2). This one “world ocean” covers 71% of
Earth’s surface and contains 97.5% of its water. The oceans
It’s been said that our planet “Earth” should more properly take up most of the hydrosphere, influence the atmosphere
be named “Ocean.” After all, ocean water covers most of our and lithosphere, and encompass much of the biosphere (p. 78).
planet’s surface. The oceans are an important component of Let’s first briefly survey the physical and chemical makeup of
Earth’s interconnected aquatic systems (p. 410). The vast the oceans—for although they may look homogenous from
majority of rivers empty into oceans (a small number of rivers a beach, boat, or airplane, marine systems are complex and
empty into inland seas), so the oceans receive most of the dynamic.
inputs of water, sediments, pollutants, and organisms carried CHAPTER 16 • M AR in E A nd Co A s TA l s ys TEM s A nd R E sou R CE s
by freshwater systems.
The oceans touch and are touched by virtually every envi-
ronmental system and every human endeavor. They shape our Seafloor topography can be rugged
planet’s climate, teem with biodiversity, provide us resources, Most maps depict oceans as smooth swaths of blue, but when
and facilitate our transportation and commerce. Even if you we examine what’s beneath the waves we see that the geol-
live in a landlocked region far from the coast, the oceans affect ogy of the ocean floor can be intricate. Underwater volcanoes
you. They provide fish for people to eat in Iowa, they sup- shoot forth enough magma to build islands above sea level,
ply crude oil for cars in New Mexico, and they influence the such as the Hawaiian Islands (p. 59). Steep canyons as large
weather in Tennessee. as Arizona’s Grand Canyon lie just offshore of some conti-
nents. The lowest spot in the oceans—the Mariana Trench in
Oceans cover most of Earth’s surface the South Pacific—is deeper than Mount Everest is high, by
over 2.1 km (1.3 mi). Our planet’s longest mountain range is
The world’s five oceans—Pacific, Atlantic, Indian, Arctic, and under water: the Mid-Atlantic Ridge (p. 52) runs the length of
Southern—are all connected, comprising a single vast body the Atlantic Ocean. 439

M16_WITH7428_05_SE_C16.indd 439 12/12/14 3:06 PM