Sustaining Aquatic Biodiversity

Core Case Study: A Biological Roller Coaster Ride in Lake Victoria  Lake Victoria has lost their endemic fish species to large introduced predatory fish. Figure 12-1

Core Case Study: A Biological Roller Coaster Ride in Lake Victoria  Reasons for Lake Victoria’s loss of biodiversity: Introduction of Nile perch. Introduction of Nile perch. Lake experienced algal blooms from nutrient runoff. Lake experienced algal blooms from nutrient runoff. Invasion of water hyacinth has blocked sunlight and deprived oxygen. Invasion of water hyacinth has blocked sunlight and deprived oxygen. Nile perch is in decline because it has eaten its own food supply. Nile perch is in decline because it has eaten its own food supply.

Three General Patterns of Marine Biodiversity  The greatest marine biodiversity occurs in coral reefs, estuaries, and the deep-ocean floor  Biodiversity is higher near coasts than in the open sea because of the greater variety of producers and habitats in coastal areas  Biodiversity is higher in the bottom region of the ocean than in the surface region because of the greater variety of habitats and food sources on the ocean bottom

HUMAN IMPACTS ON AQUATIC BIODIVERSITY  Human activities have destroyed, disrupted or degraded a large proportion of the world’s coastal, marine and freshwater ecosystems. Approximately 20% of the world's coral reefs have been destroyed. Approximately 20% of the world's coral reefs have been destroyed. During the past 100 years, sea levels have risen centimeters. During the past 100 years, sea levels have risen centimeters. We have destroyed more than 1/3 of the world’s mangrove forests for shipping lanes. We have destroyed more than 1/3 of the world’s mangrove forests for shipping lanes.

Shrimp farms in areas that were once mangrove forests

Additional ways humans degrade our ocean environment

HUMAN IMPACTS ON AQUATIC BIODIVERSITY  Area of ocean before and after a trawler net, acting like a giant plow, scraped it. Figure 12-2

HUMAN IMPACTS ON AQUATIC BIODIVERSITY  Harmful invasive species are an increasing threat to marine and freshwater biodiversity. Bioinvaders are blamed for about 2/3 of fish extinctions in the U.S. between Bioinvaders are blamed for about 2/3 of fish extinctions in the U.S. between  Almost half of the world’s people live on or near a coastal zone and 80% of ocean water pollution comes from land-based human activities.

Asian Rice Eel

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

It’s just a plastic bag! It can’t hurt anyone. Sea turtle off the coast of Florida

What can you do to make sure this does not continue?

Overfishing and Extinction: Gone Fishing, Fish Gone  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. Big fish are becoming scarce. Smaller fish are next. Smaller fish are next. We throw away 30% of the fish we catch. We throw away 30% of the fish we catch. We needlessly kill sea mammals and birds. We needlessly kill sea mammals and birds.

Human impacts on marine biodiversity Coral reef destruction Sea level rising Destruction of mangrove forests Trawler nets destroying ocean floor Invasive species Coastal development Trash Overfishing

Industrial fish harvesting methods  Trawler fishing: dragging net along ocean floor  Purse-seine fishing: surround fish with net  Long-line fishing: 80 miles of fishing line with thousands of baited hooks  Drift-net fishing: 80 miles of drifting nets below the surface

Problems with industrial fish harvesting methods  Trawler fishing: like clear-cutting forest; destroys ocean floor; captures endangered seals and turtles  Purse-seine fishing: kills hundreds of dolphins  Long-line fishing: hooks endangered sea turtles, albatross, pilot whales, sharks, dolphins  Drift-net fishing: kills non-target fish species and marine mammals

Fig. 12-A, p. 255 Fish farming in cage Trawler fishing Spotter airplane Sonar Trawl flap Trawl lines Purse-seine fishing Trawl bag Fish school Drift-net fishing Long line fishing Lines with hooks Fish caught by gills Deep sea aquaculture cage Float Buoy

Trawler fishing By-catch

Purse-seine fishing

Long-line fishing

Several countries have banned the use of drift nets or they are carefully monitoring the use of drift nets

Drift-nets catch and kill anything caught in its net

Why is it Difficult to Protect Aquatic Biodiversity?  Rapid increasing human impacts, the invisibility of problems, citizen unawareness, and lack of legal jurisdiction hinder protection of aquatic biodiversity. Human ecological footprint is expanding. Human ecological footprint is expanding. Much of the damage to oceans is not visible to most people. Much of the damage to oceans is not visible to most people. Many people incorrectly view the oceans as an inexhaustible resource. Many people incorrectly view the oceans as an inexhaustible resource.

PROTECTING AND SUSTAINING MARINE BIODIVERSITY  Laws, international treaties, and education can help reduce the premature extinction of marine species.  Since 1989 the U.S. government has required offshore shrimp trawlers to use turtle exclusion devices (TEDs). Sea turtle tourism brings in almost three times as much money as the sale of turtle products. Sea turtle tourism brings in almost three times as much money as the sale of turtle products.

PROTECTING AND SUSTAINING MARINE BIODIVERSITY  Six of the world’s seven major turtle species are threatened or endangered because of human activities. Figure 12-4

Laws and international treaties protecting marine biodiversity  CITES  Global Treaty on Migratory Species  Marine Mammal Protection Act  ESA  Whale Conservation and Protection Act  International Convention on Biological Diversity

Exclusive Economic Zone

PROTECTING AND SUSTAINING MARINE BIODIVERSITY  Fully protected marine reserves make up less than 0.3% of the world’s ocean area. Studies show that fish populations double, size grows by almost a third, reproduction triples and species diversity increases by almost one fourth. Studies show that fish populations double, size grows by almost a third, reproduction triples and species diversity increases by almost one fourth.  Some communities work together to develop integrated plans for managing their coastal areas.

Integrated Coastal Management Fisheries scientists Conservationists Citizens Business interests Developers Politicians Competing for the same resource – identify shared problems and goals and attempt to develop workable, cost-effective, and adaptable solutions that preserve biodiversity and environmental quality while meeting economic and social needs.

Revamping Ocean Policy  Two recent studies called for an overhaul of U.S. ocean policy and management. Develop unified national policy. Develop unified national policy. Double federal budget for ocean research. Double federal budget for ocean research. Centralize the National Oceans Agency. Centralize the National Oceans Agency. Set up network of marine reserves. Set up network of marine reserves. Reorient fisheries management towards ecosystem function. Reorient fisheries management towards ecosystem function. Increase public awareness. Increase public awareness.

Fig. 12-7, p. 261 Solutions Managing Fisheries Fishery Regulations Set catch limits well below the maximum sustainable yield Improve monitoring and enforcement of regulations Economic Approaches Sharply reduce or eliminate fishing subsidies Charge fees for harvesting fish and shellfish from publicly owned offshore waters Certify sustainable fisheries Protected Areas Establish no-fishing areas Establish more marine protected areas Rely more on integrated coastal management Consumer Information Label sustainably harvested fish Publicize overfished and threatened species Bycatch Use wide-meshed nets to allow escape of smaller fish Use net escape devices for sea birds and sea turtles Ban throwing edible and marketable fish back into the sea Aquaculture Restrict coastal locations for fish farms Control pollution more strictly Depend more on herbivorous fish species Nonnative Invasions Kill organisms in ship ballast water Filter organisms from ship ballast water Dump ballast water far at sea and replace with deep-sea water

PROTECTING, SUSTAINING, AND RESTORING WETLANDS  Requiring government permits for filling or destroying U.S. wetlands has slowed their loss, but attempts to weaken this protection continue. Figure 12-8

Fig. 12-9, p. 264 Solutions Protecting Wetlands Legally protect existing wetlands Steer development away from existing wetlands Use mitigation banking only as a last resort Require creation and evaluation of a new wetland before destroying an existing wetland Restore degraded wetlands Try to prevent and control invasions by nonnative species

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

Restoring the Florida Everglades  The project has been attempting to restore the Everglades and Florida water supplies. Figure 12-10

PROTECTING, SUSTAINING, AND RESTORING LAKES AND RIVERS  Lakes are difficult to manage and are vulnerable to planned or unplanned introductions of nonnative species.  For decades, invasions by nonnative species have caused major ecological and economic damage to North America’s Great lakes. Sea lamprey, zebra mussel, quagga mussel, Asian carp. Sea lamprey, zebra mussel, quagga mussel, Asian carp.

PROTECTING, SUSTAINING, AND RESTORING LAKES AND RIVERS  Dams can provide many human benefits but can also disrupt some of the ecological services that rivers provide. 119 dams on Columbia River have sharply reduced (94% drop) populations of wild salmon. 119 dams on Columbia River have sharply reduced (94% drop) populations of wild salmon. U.S. government has spent $3 billion in unsuccessful efforts to save the salmon. U.S. government has spent $3 billion in unsuccessful efforts to save the salmon. Removing hydroelectric dams will restore native spawning grounds. Removing hydroelectric dams will restore native spawning grounds.

PROTECTING, SUSTAINING, AND RESTORING LAKES AND RIVERS  We can help sustain freshwater fisheries by building and protecting populations of desirable species, preventing over-fishing, and decreasing populations of less desirable species.  A federal law helps protect a tiny fraction of U.S. wild and scenic rivers from dams and other forms of development. National Wild and Scenic Rivers Act (1968). National Wild and Scenic Rivers Act (1968).

Fig , p. 267 Deliver nutrients to sea to help sustain coastal fisheries Deposit silt that maintains deltas Purify water Renew and renourish wetlands Provide habitats for wildlife Natural Capital Ecological Services of Rivers

The End