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47 Cards in this Set

  • Front
  • Back
___________ is a large shallow lake in East Africa in ecological trouble.

In 1980 it contained _____ species of endemic (found no where else) cichlids, but today only _____ species survive.
Lake Victoria

500

200
The factors causing this loss of biodiversity in Lake Victoria include:
1) introduction of Nile perch, a large predator

2) large algae blooms from agricultural and urban runoff
Poverty has increased in the local population due to mechanized fishing for ____________, which has put small-scale fishermen out of business, and has caused local forests to be depleted of firewood, which is used to smoke the perch. Now, it is declining as its food supply diminishes.
Nile perch
What are the major threats to aquatic biodiversity?
1) coral reefs, estuaries and the deep-ocean floor have the greatest marine diversity

2) biodiversity is higher near the coasts

3) because of greater habitat and food variety, the ocean floor has more biodiversity than the ocean surface
_________ and _________are the greatest threats to marine and freshwater ecosystems.
Habitat loss

degradation
Ocean fishes spawn in ____________, ____________, ____________, and _________.

Unfortunately, these are the areas with the greatest human activity, and coastal habitats are disappearing 2-10 times quicker than tropical forests.
coral reefs

mangrove forests

coastal wetlands

rivers
_________ operations and ________________ that use trawls are degrading the ocean bottom.
Dredging (clean, deepen or widen)

fishing boats
In the _____________, an agreement to stop bottom trawling in the South Pacific has been reached, but enforcement will be difficult.
United Nations
In freshwater aquatic zones, dams and excessive water withdrawal from lakes and rivers disrupts flow and habitats.

Today ___% of freshwater fish species are threatened with premature extinction.
51 %
The deliberate or accidental introduction of harmful _________ ________ displaces many native species and disrupts ecosystem services.
invasive species
The Nature Conservancy has reported that ___% of the world’s coastal waters are being colonized by invasive species, and bioinvaders are blamed for __ / __ of the fish extinctions in the U.S. from 1900-2000.

Two major sources of these invaders are ______________ and ________, such as aquarium hobbyists that dump tanks into nearby streams and lakes, a particularly bad problem in Florida.

We may be able to use biological controls to fight some invasive species seems, but these programs could just introduce another pest.
84 %

2 / 3

ship ballast water

consumers
By 2020, ___ % of the world population will live in gigantic cities along marine coastlines, and this population growth will increase the pollution levels and aquatic habitat destruction.
80 %
In 2008 scientists found only __% of the ocean was not affected by pollution.
4
___________ resulting from inputs of nitrogen and phosphorus causes fish kills, algal blooms, and degradation of ecological services.
Eutrophication
______________ has caused the oceans to rise (4-8 inches in the last 100 years) and some models estimate that by 2100 it will have risen by 5.2 feet.

We will lose coral reefs and low lying islands, and much of Louisiana’s coastline will be flooded, including parts of New Orleans.
Climate change (global warming)
Historically, overfishing tended to occur along coastal areas, but today, given the fishing capacity of industrialized fishing fleets, all ocean areas can be exploited, and target fish species can be ___% depleted in 10-15 years.
80
__________________ occurs when a species is no longer profitable to harvest.

Historically this was a temporary depletion of fish, and by closing the fishery stocks were often able to recover.

In 1992, Canada’s cod fishery was closed, putting 20,000 fishermen and processors out of work and severely damaging the economy.

The cod population has not recovered, which created a “domino effect.”

Fishermen first turned to ________, but when these large predators became depleted, ray and skate populations exploded, which has caused a significant decline in ________________.

Mechanization of fishing fleets has changed the dynamics of fishermen, and fishing has had some unintended consequences (Principle of Ecosystem relationships???)
Commercial extinction

sharks

bay scallops
The most endangered of the large fishes is the ___________.

It is the most desirable fish for sushi and sashimi, and with a typical weight of 340 kilograms (750 pounds), can sell for as much as $880 per kilogram ($400 per pound).
bluefin tuna
Fishing boats usually target one commercial species, but the nets and lines catch many non-target species, called ________.
bycatch
___/___ of the world’s annual fish catch is thrown overboard dead or dying, and many seabirds and marine mammals, such as seals and dolphins, become part of the bycatch when entangled in fishing nets.
1/3
More than any other species group, _______ & _________________ are threatened with extinction by human activities; it has been estimated that ___% of marine fishes and ___% of freshwater fishes face extinction within the next fifty years.
marine & freshwater fishes

34 %

71 %
Methods the fleets use include:
1. Trawling
2. Purse-seining
3. Longlining
4. Drift-net fishing
~For species on or near the ocean floor, uses funnel-shaped nets weighted down with chains and metal plates.

~These nets can destroy bottom habitats, somewhat like clear cutting the ocean floor.
Trawling
~For surface dwelling species, spotter planes locate a school of fish and the fishing vessel encloses it in the purse seine.

~Historically these nets caught and killed large numbers of dolphins swimming with the fish schools.

~However, international furor over dolphin mortality has changed gears and fishing methods, substantially reducing mortality rates.
Purse-seining
~Use baited hooks attached along a weighted (bottom species) or floating (surface species) line.

~Lines up to 130 kilometers (80 miles) are hung with thousands of baited hooks and deployed.

~Unfortunately, longlines are not very selective, and threatened fishes (billfishes like marlin), sea turtles, dolphins, and sea birds are often killed.
Longlining
~Fish are caught in huge nets that hang 15-800 meters (50 to 2400 feet) below the surface and may be up to 64 kilometers (40 miles) long.

~This method leads to overfishing and large quantities of bycatch.

~The U.N. has suggested a ban on the use of drift nets longer than 2.5 kilometers (1.6 miles), but compliance is voluntary.
Drift-net fishing
Protecting marine biodiversity is difficult because:
1) it’s difficult to monitor impacts of human behavior

2) damage to the ocean is not visible to most people

3) people believe the ocean can absorb all our waste and produce all the seafood we need

4) most of the world’s ocean area lies outside the jurisdiction of any one country
the areas where each country may (or may not) have quota agreements with foreign governments allowing them to fish
exclusive economic zones
Protection of marine fisheries includes:
1. National and international laws and treaties

2. Economic incentives, such as ecotourism

3. Establishment of marine protected areas (MPAs) where some or all human activities are banned to help marine biodiversity

4. An ecosystem approach with global, fully-protected marine reserves

5. Community based integrated coastal management
Where some or all human activities are banned to help marine biodiversity.

There are 4,000 worldwide and 200 in U.S. waters.

Unfortunately, many offer only partial protection because they allow certain extraction activities.

California has a highly developed system, with banned and strictly limited fishing in its extensive network of coastal MPAs.
MPA
How Should We Manage and Sustain Marine Fisheries?
1. Make the best possible estimates of fish population size and effects of fishing.
(MSY, OSY)

2. Strictly regulate fish harvest.

3. Reduce government subsidies to fishermen.

4. Use the marketplace to control overfishing.
(ITRs)

5. Proper labeling and education of consumers to make sustainable choices.
-Model was used to project the maximum number of fish that could be harvested without causing a population drop.

-This model has failed to protect many marine organisms because it is hard to estimate population size, growth rate, and harvest effects for one species without considering effects on other marine species.
maximum sustained yield (MSY)
-Model attempts to take into account interactions among species, and newer approaches add competition, predator-prey interactions, and large marine system habitat concerns to the models.
optimum sustained yield (OSY)
-Used by governments to control access to certain fisheries.

-The government issues a vessel owner a percentage of the total allowable catch for a given year.

-The owner may catch the fish or sell the ITR to another fisherman as private property.

-The U.S. uses ITRs to regulate Alaska’s halibut fishery and the number of fishermen has declined, allowing for a longer season, safer working conditions, and more profit.
individual transfer rights (ITRs)
Wetlands serve as _______ ________: wetlands around Lake Victoria (Africa) have historically filtered human and animal waste, keeping the lake water clean enough for human consumption.
natural filters
allows for the destruction of wetlands, if the same type wetland is created or restored in another location
Mitigation banking
Creating functioning wetlands is difficult and the U.S. wetland banking system requires __-__ hectares of created wetland for each one destroyed.

Private investment bankers often buy wetland areas to restore or upgrade, earning wetland bank credits they can sell to developers.

Ecologists argue that replacement wetlands should be created and evaluated before natural wetlands are destroyed.
2-3
The ________________ was originally a 100 kilometer wide (60 mile wide), knee deep sheet of water that flowed south from Lake Okeechobee to Florida Bay, called the “____ __ _____.”

Starting in 1948, a massive water control project was begun to drain the Everglades and provide Florida’s growing population with water, flood protection, and agricultural land.
Florida Everglades

" River of Grass "
The wandering ______________ was transformed into a straight 84 kilometer (56 mile) canal draining the northern Everglades, resulting in a ___% loss of the birds and mammals from Everglades National Park.

Large volumes of freshwater were allowed to flow into Florida Bay and with high nutrient agricultural runoff, which resulted in large algae blooms that threatened coral reefs, diving, and fishing.

The huge plumbing project is destroying a major source of tourism income and cutting off the supply of water it was intended to create.
Kissimmee River

90
In 1990, Florida and the federal government agreed to the world’s largest ecological restoration project, the ________________________.
Comprehensive Everglades Restoration Plan (CERP)
Comprehensive Everglades Restoration Plan (CERP) goals:
1) restore the Kissimmee River

2) remove 400 kilometers (240 miles) of canals and levees

3) buy 240 sq kilometers (93 sq miles) of farmland and flood it

4) create 18 reservoirs and underground water storage areas

5) build canals and a pumping system to return 80% of water flowing out to sea to the Everglades
___ percent of the world’s rivers have been dammed or engineered, and combined with the loss of wetlands, has resulted in a situation where ___________________________________.
40

aquatic species are now crowded into half their original habitat areas
The _________________ has 119 dams and 19 are major generators of hydroelectric power.

The river supplies water to major urban areas and for irrigating crop land, and was once home to ___________ _______ __________stocks.

The dam system does not allow fish access to _____________ and has eliminated 94% of the Pacific salmon population on the river, with 9 salmon groups (called ________________________) listed as threatened or endangered.

Since 1980, the U.S. government has spent $3 billion to save the salmon, with little effect.
Columbia River

anadromous wild salmon

spawning areas

evolutionarily significant units
Land and water are always connected, and protecting ____________ protects all freshwater systems.
watersheds
Congress passed the ______________________ to protect the remaining 2% of rivers that are inaccessible except by trails and are still free of dams.
National Wild and Scenic Rivers Act
Sustainable management of freshwater fisheries, commercial and sport fishes, includes:
1) no overfishing

2) reduction or elimination of invasive species

3) regulations on the length of fishing seasons

4) regulations on the size and number of fishes caught

5) management of habitat
E. O. Wilson has proposed these priorities for sustaining biodiversity and ecosystem services:

1) Complete the ________ of terrestrial and aquatic biodiversity
2) Keep remaining _______ ________ intact
3) Protect and restore ____ and ____ systems, the most threatened of our ecosystems
4) Identify biodiversity _______ for special restoration attention
5) Start ecological _______ in damaged areas
6) Make conservation ______ rewarding for people, so they will protect and sustain resources
1) mapping

2) old-growth forests

3) lakes, river

4) hotspots

5) restoration

6) financially