What are the basic types of aquatic life zones and what factors influence the kinds of life they contain?


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What are the basic types of aquatic life zones and what factors influence the kinds of life they contain?

  • What are the basic types of aquatic life zones and what factors influence the kinds of life they contain?

  • What are the major types of freshwater life zones, and how do human activities affect them?



What do we know about aquatic biodiversity, and what is its economic and ecological importance?

  • What do we know about aquatic biodiversity, and what is its economic and ecological importance?

  • How are human activities affecting aquatic biodiversity?

  • How can we manage and sustain the world’s marine fisheries?



How can we protect, sustain, and restore wetlands?

  • How can we protect, sustain, and restore wetlands?

  • How can we protect, sustain, and restore lakes, rivers, and freshwater fisheries?



Why is water so important, how much freshwater is available to us, and how much of it are we using?

  • Why is water so important, how much freshwater is available to us, and how much of it are we using?

  • What causes freshwater shortages, and what can be done about this problem?

  • What are the advantages and disadvantages of withdrawing groundwater?

  • What are the advantages and disadvantages of using dams and reservoirs to supply more water?



What are the advantages and disadvantages of transferring large amounts of water from one place to another?

  • What are the advantages and disadvantages of transferring large amounts of water from one place to another?

  • Can removing salt from seawater solve our water supply problems?

  • How can we waste less water?

  • How can we use the earth’s water more sustainably?

  • What causes flooding, and what can we do about it?



Water keeps us alive, moderates climate, sculpts the land, removes and dilutes wastes and pollutants, and moves continually through the hydrologic cycle.

  • Water keeps us alive, moderates climate, sculpts the land, removes and dilutes wastes and pollutants, and moves continually through the hydrologic cycle.

  • Only about 0.02% of the earth’s water supply is available to us as liquid freshwater.



Comparison of population sizes and shares of the world’s freshwater among the continents.

  • Comparison of population sizes and shares of the world’s freshwater among the continents.



Some precipitation infiltrates the ground and is stored in soil and rock (groundwater).

  • Some precipitation infiltrates the ground and is stored in soil and rock (groundwater).

  • Water that does not sink into the ground or evaporate into the air runs off (surface runoff) into bodies of water.

    • The land from which the surface water drains into a body of water is called its watershed or drainage basin.




We currently use more than half of the world’s reliable runoff of surface water and could be using 70-90% by 2025.

  • We currently use more than half of the world’s reliable runoff of surface water and could be using 70-90% by 2025.

  • About 70% of the water we withdraw from rivers, lakes, and aquifers is not returned to these sources.

  • Irrigation is the biggest user of water (70%), followed by industries (20%) and cities and residences (10%).



The saltiness.

  • The saltiness.





Aquatic systems contain floating, drifting, swimming, bottom-dwelling, and decomposer organisms.

  • Aquatic systems contain floating, drifting, swimming, bottom-dwelling, and decomposer organisms.

    • Plankton: important group of weakly swimming, free-floating biota.
      • Phytoplankton (plant), Zooplankton (animal), Ultraplankton (photosynthetic bacteria)
    • Necton: fish, turtles, whales.
    • Benthos: bottom dwellers (barnacles, oysters).
    • Decomposers: breakdown organic compounds (mostly bacteria).


Description – small drifting plants

  • Description – small drifting plants

  • Niche – they are producers that support most aquatic food chains

  • Example – cyanobacteria & many types of algae



Description – herbivores that feed on phytoplankton or other zooplankton

  • Description – herbivores that feed on phytoplankton or other zooplankton

  • Niche – food stock for larger consumers

  • Example – krill; small crustaceans



Description – larger, strong-swimming consumers

  • Description – larger, strong-swimming consumers

  • Niche – top consumers in the aquatic ecosystem

  • Example – fish, turtles, and whales



Description – bottom-dwelling creatures

  • Description – bottom-dwelling creatures

  • Niche – primary consumers, decomposers

  • Example – barnacles, oysters, and lobsters





Freshwater life zones include:

  • Freshwater life zones include:

    • Standing (lentic) water such as lakes, ponds, and inland wetlands.
    • Flowing (lotic) systems such as streams and rivers.






Water flowing from mountains to the sea creates different aquatic conditions and habitats.

  • Water flowing from mountains to the sea creates different aquatic conditions and habitats.



A narrow zone of cold, clear water that rushes over waterfalls and rapids. Large amounts of oxygen are present. Fish are also present. Ex. trout.

  • A narrow zone of cold, clear water that rushes over waterfalls and rapids. Large amounts of oxygen are present. Fish are also present. Ex. trout.



Slower-moving water, less oxygen, warmer temperatures, and lots of algae and cyanobacteria.

  • Slower-moving water, less oxygen, warmer temperatures, and lots of algae and cyanobacteria.



Gravity

  • Gravity





Life in most aquatic systems is found in surface, middle, and bottom layers.

  • Life in most aquatic systems is found in surface, middle, and bottom layers.

  • Temperature, access to sunlight for photosynthesis, dissolved oxygen content, nutrient availability changes with depth.

    • Euphotic zone (upper layer in deep water habitats): sunlight can penetrate.


Lakes are large natural bodies of standing freshwater formed from precipitation, runoff, and groundwater seepage consisting of:

  • Lakes are large natural bodies of standing freshwater formed from precipitation, runoff, and groundwater seepage consisting of:

    • Littoral zone (near shore, shallow, with rooted plants).
    • Limnetic zone (open, offshore area, sunlit).
    • Profundal zone (deep, open water, too dark for photosynthesis).
    • Benthic zone (bottom of lake, nourished by dead matter).


A shallow area near the shore, to the depth at which rooted plants stop growing. Ex. frogs, snails, insects, fish, cattails, and water lilies.

  • A shallow area near the shore, to the depth at which rooted plants stop growing. Ex. frogs, snails, insects, fish, cattails, and water lilies.



Open, sunlit water that extends to the depth penetrated by sunlight.

  • Open, sunlit water that extends to the depth penetrated by sunlight.



Deep, open water where it is too dark for photosynthesis.

  • Deep, open water where it is too dark for photosynthesis.







The temperature difference in deep lakes where there are warm summers and cold winters.

  • The temperature difference in deep lakes where there are warm summers and cold winters.



During summer and winter in deep temperate zone lakes the become stratified into temperature layers and will overturn.

  • During summer and winter in deep temperate zone lakes the become stratified into temperature layers and will overturn.

    • This equalizes the temperature at all depths.
    • Oxygen is brought from the surface to the lake bottom and nutrients from the bottom are brought to the top.


During the summer, lakes become stratified into different temperature layers that resist mixing because summer sunlight warms surface waters, making them less dense.

  • During the summer, lakes become stratified into different temperature layers that resist mixing because summer sunlight warms surface waters, making them less dense.



The middle layer that acts as a barrier to the transfer of nutrients and dissolved oxygen.

  • The middle layer that acts as a barrier to the transfer of nutrients and dissolved oxygen.



As the temperatures begin to drop, the surface layer becomes more dense, and it sinks to the bottom. This mixing brings nutrients from the bottom up to the surface and sends oxygen to the bottom.

  • As the temperatures begin to drop, the surface layer becomes more dense, and it sinks to the bottom. This mixing brings nutrients from the bottom up to the surface and sends oxygen to the bottom.



As top water warms and ice melts, it sinks through and below the cooler, less dense water, sending oxygen down and nutrients up.

  • As top water warms and ice melts, it sinks through and below the cooler, less dense water, sending oxygen down and nutrients up.





Inland wetlands act like natural sponges that absorb and store excess water from storms and provide a variety of wildlife habitats.

  • Inland wetlands act like natural sponges that absorb and store excess water from storms and provide a variety of wildlife habitats.





An area of temporarily flooded, often silty land beside a river or lake.

  • An area of temporarily flooded, often silty land beside a river or lake.



A lowland region permanently covered with water.

  • A lowland region permanently covered with water.



An area down by a river or stream where lots of hardwoods, like oaks, grow.

  • An area down by a river or stream where lots of hardwoods, like oaks, grow.



These are depressions that hold water out on the prairie, especially up north in Canada. It is a very good duck habitat.

  • These are depressions that hold water out on the prairie, especially up north in Canada. It is a very good duck habitat.



A wet area that over time fills in (the last stage of succession is peat moss). It can be very deep. In Ireland, they burn this for wood.

  • A wet area that over time fills in (the last stage of succession is peat moss). It can be very deep. In Ireland, they burn this for wood.



They filter & purify water.

  • They filter & purify water.

  • Habitat for many animals and plants.



Developers and farmers want Congress to revise the definition of wetlands. This would make 60-75% of all wetlands unavailable for protection. The Audubon Society estimates that wetlands provide water quality protection worth $1.6 billion per year, and they say if that wetlands are destroyed, the U.S. would spend $7.7 billion to $31 billion per year in additional flood-control costs.

  • Developers and farmers want Congress to revise the definition of wetlands. This would make 60-75% of all wetlands unavailable for protection. The Audubon Society estimates that wetlands provide water quality protection worth $1.6 billion per year, and they say if that wetlands are destroyed, the U.S. would spend $7.7 billion to $31 billion per year in additional flood-control costs.





A partially enclosed area of coastal water where sea water mixes with freshwater.

  • A partially enclosed area of coastal water where sea water mixes with freshwater.



The ground here is saturated with water and there is little oxygen, so decay takes place slowly. It has a surface inlet and outlet, and contains many invertebrates. It is also the breeding ground for many ocean animals. Ex. crabs and shellfish.

  • The ground here is saturated with water and there is little oxygen, so decay takes place slowly. It has a surface inlet and outlet, and contains many invertebrates. It is also the breeding ground for many ocean animals. Ex. crabs and shellfish.



These are along warm, tropical coasts where there is too much silt for coral reefs to grow. It is dominated by salt-tolerant trees called mangroves (55 different species exist). It also helps to protect the coastline from erosion and provides a breeding nursery for some 2000 species of fish, invertebrates, and plants.

  • These are along warm, tropical coasts where there is too much silt for coral reefs to grow. It is dominated by salt-tolerant trees called mangroves (55 different species exist). It also helps to protect the coastline from erosion and provides a breeding nursery for some 2000 species of fish, invertebrates, and plants.



Just one acre of estuary provides $75,000 worth of free waste treatment, and has a value of about $83,000 when recreation and fish for food are included.

  • Just one acre of estuary provides $75,000 worth of free waste treatment, and has a value of about $83,000 when recreation and fish for food are included.

  • Prime Kansas farmland has a top value of $1,200 and an annual production value of $600.





The world’s largest ecological restoration project involves trying to undo some of the damage inflicted on the Everglades by human activities.

  • The world’s largest ecological restoration project involves trying to undo some of the damage inflicted on the Everglades by human activities.

    • 90% of park’s wading birds have vanished.
    • Other vertebrate populations down 75-95%.
    • Large volumes of water that once flowed through the park have been diverted for crops and cities.
    • Runoff has caused noxious algal blooms.


As Miami develops, it encroaches on everglades. Plus, it prompts people vs. wildlife. It is freshwater and local areas are draining it.

  • As Miami develops, it encroaches on everglades. Plus, it prompts people vs. wildlife. It is freshwater and local areas are draining it.



The project has been attempting to restore the Everglades and Florida water supplies.

  • The project has been attempting to restore the Everglades and Florida water supplies.



Build huge aqueduct, or find other sources of fresh water an protect it federally under endangered species act, etc.

  • Build huge aqueduct, or find other sources of fresh water an protect it federally under endangered species act, etc.





Leonardo da Vinci said that “Water is the driver of nature.” Without water, the other nutrient cycles would not exist in their present forms, and current forms of life on earth could not exist.

  • Leonardo da Vinci said that “Water is the driver of nature.” Without water, the other nutrient cycles would not exist in their present forms, and current forms of life on earth could not exist.





The strong forces of attraction between molecules of water.

  • The strong forces of attraction between molecules of water.



Water changes temp very slowly because it can store heat. This protects living organisms from the shock of abrupt temperature changes.

  • Water changes temp very slowly because it can store heat. This protects living organisms from the shock of abrupt temperature changes.



The temperature at which water turns to vapor.

  • The temperature at which water turns to vapor.



Water can dissolve a wide variety of compounds. This means it can easily become polluted by water-soluble wastes.

  • Water can dissolve a wide variety of compounds. This means it can easily become polluted by water-soluble wastes.



Ice has a lower density than liquid water. Thus, ice floats on water.

  • Ice has a lower density than liquid water. Thus, ice floats on water.





Examples – streams, rivers, and lakes

  • Examples – streams, rivers, and lakes

  • Source – precipitation

  • Watershed – Ex. small streams  larger streams  rivers  sea



Aquifers–porous rock w/ water flowing through

  • Aquifers–porous rock w/ water flowing through

  • Water Table – the level of earth’s land crust to which the aquifer is filled

  • Renewability – the circulation rate of groundwater is slow (300 to 4,600 years).



Irrigation – watering crops

  • Irrigation – watering crops

  • Industry – coolant (power plant)

  • Domestic and Municipal – drinking, sewage, bathwater, dishwater & laundry





Problems include flooding, pollution of water supply, and sewage seeping into the ground.

  • Problems include flooding, pollution of water supply, and sewage seeping into the ground.



Heavy rainfall, rapid snowmelt, removal of vegetation, and destruction of wetlands cause flooding.

  • Heavy rainfall, rapid snowmelt, removal of vegetation, and destruction of wetlands cause flooding.

  • Floodplains, which usually include highly productive wetlands, help provide natural flood and erosion control, maintain high water quality, and recharge groundwater.

  • To minimize floods, rivers have been narrowed with levees and walls, and dammed to store water.



Comparison of St. Louis, Missouri under normal conditions (1988) and after severe flooding (1993).

  • Comparison of St. Louis, Missouri under normal conditions (1988) and after severe flooding (1993).



Human activities have contributed to flood deaths and damages.

  • Human activities have contributed to flood deaths and damages.









Examples include drought and expanding deserts.

  • Examples include drought and expanding deserts.



Lake levels drop, recreation use drops, fisheries drop, and salinization occurs. Ex. Soviet Union (Aral Sea); the inland sea drained the river that fed into it. Now it’s a huge disaster (read pg. 305 in text).

  • Lake levels drop, recreation use drops, fisheries drop, and salinization occurs. Ex. Soviet Union (Aral Sea); the inland sea drained the river that fed into it. Now it’s a huge disaster (read pg. 305 in text).



Diverting water from the Aral Sea and its two feeder rivers mostly for irrigation has created a major ecological, economic, and health disaster.

  • Diverting water from the Aral Sea and its two feeder rivers mostly for irrigation has created a major ecological, economic, and health disaster.

    • About 85% of the wetlands have been eliminated and roughly 50% of the local bird and mammal species have disappeared.
    • Since 1961, the sea’s salinity has tripled and the water has dropped by 22 meters most likely causing 20 of the 24 native fish species to go extinct.


This harms endangered species, and salt water can seep in.

  • This harms endangered species, and salt water can seep in.



Water is poured onto soil and evaporates. Over time, as this is repeated, nothing will grow there anymore.

  • Water is poured onto soil and evaporates. Over time, as this is repeated, nothing will grow there anymore.





The polluted Mississippi River (non-source point pollution) has too much phosphorus.

  • The polluted Mississippi River (non-source point pollution) has too much phosphorus.

  • In the Eerie Canal, which connects the ocean to the Great Lakes, lampreys came in and depleted the fish. The zebra mollusk is also a problem in the Great Lakes.



Plant nutrients from a lake’s environment affect the types and numbers of organisms it can support.

  • Plant nutrients from a lake’s environment affect the types and numbers of organisms it can support.



Plant nutrients from a lake’s environment affect the types and numbers of organisms it can support.

  • Plant nutrients from a lake’s environment affect the types and numbers of organisms it can support.

    • Oligotrophic (poorly nourished) lake: Usually newly formed lake with small supply of plant nutrient input.
    • Eutrophic (well nourished) lake: Over time, sediment, organic material, and inorganic nutrients wash into lakes causing excessive plant growth.


Cultural eutrophication:

  • Cultural eutrophication:

    • Human inputs of nutrients from the atmosphere and urban and agricultural areas can accelerate the eutrophication process.


(like the Dead Sea) This has a huge salt concentration due to man’s draining.

  • (like the Dead Sea) This has a huge salt concentration due to man’s draining.



These are dams & reservoirs that feed from the Colorado River all the way to San Diego, LA, Palm Springs, Phoenix & Mexico. So far has worked because they haven’t withdrawn their full allocations. See pg306.

  • These are dams & reservoirs that feed from the Colorado River all the way to San Diego, LA, Palm Springs, Phoenix & Mexico. So far has worked because they haven’t withdrawn their full allocations. See pg306.



The area drained by this basin is equal to more than one-twelfth of the land area of the lower 48 states.

  • The area drained by this basin is equal to more than one-twelfth of the land area of the lower 48 states.





The Colorado River has so many dams and withdrawals that it often does not reach the ocean.

  • The Colorado River has so many dams and withdrawals that it often does not reach the ocean.

    • 14 major dams and reservoirs, and canals.
    • Water is mostly used in desert area of the U.S.
    • Provides electricity from hydroelectric plants for 30 million people (1/10th of the U.S. population).


Lake Powell, is the second largest reservoir in the U.S.

  • Lake Powell, is the second largest reservoir in the U.S.

  • It hosts one of the hydroelectric plants located on the Colorado River.



These include pollution, salt, and draining too much.

  • These include pollution, salt, and draining too much.



Sinkholes form when the roof of an underground cavern collapses after being drained of groundwater.

  • Sinkholes form when the roof of an underground cavern collapses after being drained of groundwater.



The Ogallala, the world’s largest aquifer, is most of the red area in the center (Midwest).

  • The Ogallala, the world’s largest aquifer, is most of the red area in the center (Midwest).



This is the world’s largest known aquifer, and fuels agricultural regions in the U.S. It extends from South Dakota to Texas. It’s essentially a non-renewable aquifer from the last ice age with an extremely slow recharge rate. In some cases, water is pumped out 8 to 10 times faster than it is renewed. Northern states will still have ample supplies, but for the south it’s getting thinner. It is estimated that ¼ of the aquifer will be depleted by 2020.

  • This is the world’s largest known aquifer, and fuels agricultural regions in the U.S. It extends from South Dakota to Texas. It’s essentially a non-renewable aquifer from the last ice age with an extremely slow recharge rate. In some cases, water is pumped out 8 to 10 times faster than it is renewed. Northern states will still have ample supplies, but for the south it’s getting thinner. It is estimated that ¼ of the aquifer will be depleted by 2020.





Dams, cities, farmlands, and filled-in wetlands alter and degrade freshwater habitats.

  • Dams, cities, farmlands, and filled-in wetlands alter and degrade freshwater habitats.

    • Dams, diversions and canals have fragmented about 40% of the world’s 237 large rivers.
    • Flood control levees and dikes alter and destroy aquatic habitats.
    • Cities and farmlands add pollutants and excess plant nutrients to streams and rivers.
    • Many inland wetlands have been drained or filled for agriculture or (sub)urban development.


Lake Victoria has lost their endemic fish species to large introduced predatory fish.

  • Lake Victoria has lost their endemic fish species to large introduced predatory fish.



Reasons for Lake Victoria’s loss of biodiversity:

  • Reasons for Lake Victoria’s loss of biodiversity:

    • Introduction of Nile perch.
    • Lake experienced algal blooms from nutrient runoff.
    • Invasion of water hyacinth has blocked sunlight and deprived oxygen.
    • Nile perch is in decline because it has eaten its own food supply.


As water runs off from rain, it’s supposed to get into rivers, and finally off to the sea. But when we dam rivers, less goes to the ocean, meaning the brackish water (where the river hits the ocean) becomes more salty. This is the breeding ground for many fish and invertebrates. This harms the ecology of the area.

  • As water runs off from rain, it’s supposed to get into rivers, and finally off to the sea. But when we dam rivers, less goes to the ocean, meaning the brackish water (where the river hits the ocean) becomes more salty. This is the breeding ground for many fish and invertebrates. This harms the ecology of the area.





The W.H.O. recommends there be zero colonies of bacteria per 100ml of drinking water and 200 colonies per 100ml of swimming water. The average human excretes 2 billion organisms per day (see how easily untreated sewage can contaminate water?).

  • The W.H.O. recommends there be zero colonies of bacteria per 100ml of drinking water and 200 colonies per 100ml of swimming water. The average human excretes 2 billion organisms per day (see how easily untreated sewage can contaminate water?).



These are organic wastes that can be decomposed by aerobic bacteria (causes lack of oxygen). Fish die as a result of a lack of oxygen.

  • These are organic wastes that can be decomposed by aerobic bacteria (causes lack of oxygen). Fish die as a result of a lack of oxygen.



These include acids, salts, mercury, and lead. They make water unfit to drink.

  • These include acids, salts, mercury, and lead. They make water unfit to drink.



These include oil, gas, plastics, pesticides, and detergents.

  • These include oil, gas, plastics, pesticides, and detergents.



Problems include over-drawing fresh water, pollution, and over-building so that water can’t seep into the ground.

  • Problems include over-drawing fresh water, pollution, and over-building so that water can’t seep into the ground.



There are water wars out west. California bought the water from the Colorado River, but Arizona wants it. Who owns it? The same thing is happening in Texas. More water rights are sold than the actual amount of water. How do you share water? This is a problem all over the world.

  • There are water wars out west. California bought the water from the Colorado River, but Arizona wants it. Who owns it? The same thing is happening in Texas. More water rights are sold than the actual amount of water. How do you share water? This is a problem all over the world.







Large dams and reservoirs can produce cheap electricity, reduce downstream flooding, and provide year-round water for irrigating cropland, but they also displace people and disrupt aquatic systems.

  • Large dams and reservoirs can produce cheap electricity, reduce downstream flooding, and provide year-round water for irrigating cropland, but they also displace people and disrupt aquatic systems.







There is a debate over whether the advantages of the world’s largest dam and reservoir will outweigh its disadvantages.

  • There is a debate over whether the advantages of the world’s largest dam and reservoir will outweigh its disadvantages.

    • The dam will be 2 kilometers long.
    • The electric output will be that of 18 large coal-burning or nuclear power plants.
    • It will facilitate ship travel reducing transportation costs.
    • Dam will displace 1.2 million people.
    • Dam is built over seismatic fault and already has small cracks.


Some dams are being removed for ecological reasons and because they have outlived their usefulness.

  • Some dams are being removed for ecological reasons and because they have outlived their usefulness.

    • In 1998 the U.S. Army Corps of Engineers announced that it would no longer build large dams and diversion projects in the U.S.
    • The Federal Energy Regulatory Commission has approved the removal of nearly 500 dams.
    • Removing dams can reestablish ecosystems, but can also re-release toxicants into the environment.






Removing salt from seawater by current methods is expensive and produces large amounts of salty wastewater that must be disposed of safely.

  • Removing salt from seawater by current methods is expensive and produces large amounts of salty wastewater that must be disposed of safely.

    • Distillation: heating saltwater until it evaporates, leaves behind water in solid form.
    • Reverse osmosis: uses high pressure to force saltwater through a membrane filter.


Seeding clouds with tiny particles of chemicals to increase rainfall towing icebergs or huge bags filled with freshwater to dry coastal areas have all been proposed but are unlikely to provide significant amounts of freshwater.

  • Seeding clouds with tiny particles of chemicals to increase rainfall towing icebergs or huge bags filled with freshwater to dry coastal areas have all been proposed but are unlikely to provide significant amounts of freshwater.





Sixty percent of the world’s irrigation water is currently wasted, but improved irrigation techniques could cut this waste to 5-20%.

  • Sixty percent of the world’s irrigation water is currently wasted, but improved irrigation techniques could cut this waste to 5-20%.

  • Center-pivot, low pressure sprinklers sprays water directly onto crop.

    • It allows 80% of water to reach crop.
    • Has reduced depletion of Ogallala aquifer in Texas High Plains by 30%.






The major decline in the worldwide catch of fish since 1990 is because of over-fishing.

  • The major decline in the worldwide catch of fish since 1990 is because of over-fishing.

  • By-catch- fish or animals that were not meant to be caught.



About 75% of the world’s commercially valuable marine fish species are over fished or fished near their sustainable limits.

  • About 75% of the world’s commercially valuable marine fish species are over fished or fished near their sustainable limits.

    • Big fish are becoming scarce.
    • Smaller fish are next.
    • We throw away 30% of the fish we catch.
    • We needlessly kill sea mammals and birds.






A large purse-like net is put into the ocean and is then closed like a drawstring purse to trap the fish.

  • A large purse-like net is put into the ocean and is then closed like a drawstring purse to trap the fish.

  • Tuna is a fish typically caught in purse seines

  • Dolphins are a by-catch of purse seines



Lines are put out that can be up to 80 miles long w/ thousands of baited hooks on them. These are left out free-floating for days and then the boat comes back and picks them up.

  • Lines are put out that can be up to 80 miles long w/ thousands of baited hooks on them. These are left out free-floating for days and then the boat comes back and picks them up.

  • Pilot whales, dolphins, sea turtles, and birds are by-catch of this technique.



Each net hangs as much as 50 feet below the surface and up to 34 miles long.

  • Each net hangs as much as 50 feet below the surface and up to 34 miles long.

  • Anything that comes into contact w/ these nearly invisible nets are entangled.

  • This leads to overfishing

  • Many unwanted fish and marine mammals, turtles and seabirds are caught.



Area of ocean before and after a trawler net, acting like a giant plow, scraped it.

  • Area of ocean before and after a trawler net, acting like a giant plow, scraped it.



Each year plastic items dumped from ships and left as litter on beaches threaten marine life.

  • Each year plastic items dumped from ships and left as litter on beaches threaten marine life.




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