Chapter 11 Sustaining Aquatic Biodiversity Mola Mola!

Chapter Overview Questions  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 protect and sustain marine biodiversity?  How can we manage and sustain the world’s marine fisheries?

Chapter Overview Questions (cont’d)  How can we protect, sustain, and restore wetlands?  How can we protect, sustain, and restore lakes, rivers, and freshwater fisheries?

Core Case Study: A Biological Roller Coaster Ride in Lake Victoria  Lake Victoria has lost many of its endemic fish species to large introduced predatory fish, the Nile perch. Figure 12-1

Lake Victoria Cichlids Figure 12-1 Astatotilapia latifasciata About 200 of 400 Lake Victoria endemic cichlid species have become extinct since the introduction of the Nile perch. Pundamilia nyererei Haplochromis sp. 44 "Red Tail"

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 (!)

AQUATIC BIODIVERSITY  We know fairly little about the biodiversity of the world’s marine and freshwater systems.  We know more about deep space than the abyssal zones of the ocean (why?). The greatest marine biodiversity occurs in coral reefs, estuaries and the deep ocean floor. The greatest marine biodiversity occurs in coral reefs, estuaries and the deep ocean floor. Biodiversity is higher near the coast and surface because of habitat and food source variety. Biodiversity is higher near the coast and surface because of habitat and food source variety.  The world’s marine and freshwater systems provide important ecological and economic services.

AQUATIC BIODIVERSITY  About 50% of the world’s people depend on the sea as their primary source of food. Indonesian fishing prau Lake Victoria fishers Georgia shrimper

AQUATIC BIODIVERSITY  About 90% of fish spawn in the world’s coral reefs, mangrove swamps, coastal wetlands, or rivers.

Coastal Wetlands: Salt marsh or Mangroves

Snook!

Kayaking Mangroves

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, mostly for shipping lanes. We have destroyed more than 1/3 of the world’s mangrove forests, mostly for shipping lanes. Shrimp farming is a big, new threat to mangroves Shrimp farming is a big, new threat to mangroves

Area of ocean before and after a trawler net passed by. Note: East coast shrimp trawlers work in relatively open areas and do not do this much damage 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.

Population Growth and Pollution  Each year plastic items dumped from ships and washing in to the ocean from land threaten marine life.  “Red tide” is a toxic algae bloom that is exacerbated by excess nutrients entering the water from terrestrial sources Figure 12-3

Population Growth and Pollution: Excess Nutrients  Since 1860, humans have doubled the flow of nitrogen, mostly as nitrate fertilizers, into the ocean. Figure 12-3 N P K Nitrogen Potassium “potash” Phosphorous

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 (bycatch) We throw away 30% of the fish we catch (bycatch) We needlessly kill sea mammals and birds. We needlessly kill sea mammals and birds.

Overfishing and Extinction: Gone Fishing, Fish Gone  Commercial depletion occurs when a species has been over fished to the point where it is no longer profitable as a fishery.

Overfishing and Extinction: Gone Fishing, Fish Gone  Review! When too many people using the same resource in a way that makes sense for them as individuals results in the collapse of the resource, it is called… The Tragedy of the Commons

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 a.k.a. gill netting Long line fishing Lines with hooks Fish caught by gills Deep sea aquaculture cage Float Buoy

Why is it Difficult to Protect Aquatic Biodiversity?  Human ecological footprint is increasing so rapidly  Much damage done to oceans is “invisible” to most people  Most citizens are unaware of the scope and severity of the problems  Lack of legal jurisdiction  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.

Turtle Excluder Devices (TEDs)

Bycatch Reduction Devices (BRDs)

PROTECTING AND SUSTAINING MARINE BIODIVERSITY  Six of the world’s seven major turtle species are threatened or endangered because of human activities. *beach development *harvesting eggs *turtle shell jewelry *leather made of flippers Figure 12-4

Case Study: The Florida Manatee and Water Hyacinths  Manatee can eat unwanted Water Hyacinths.  Endangered due to: Habitat loss. Habitat loss. Entanglement from fishing lines and nets. Entanglement from fishing lines and nets. Hit by speed boats. Hit by speed boats. Stress from cold. Stress from cold. Low reproductive rate Low reproductive rate Figure 12-B

Case Study: Commercial Whaling  After many of the world’s whale species were overharvested, commercial whaling was banned in 1960, but the ban may be overturned. Figure 12-6 Japan has a significant whaling industry and whale meat market

Case Study: Commercial Whaling  Despite ban, Japan, Norway, and Iceland kill about 1,300 whales of certain species for “scientific purposes”. Although meat is still sold commercially. Although meat is still sold commercially. Figure 12-5

Fig. 12-5, p. 258 Toothed whales *Sperm whale with squid Killer whale Narwhal Bottlenose dolphin Baleen whales Blue whale Fin whale Bowhead whale Right whale Sei whale Humpback whale Gray whale *Minke whale

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

Revamping Ocean Policy  Two recent studies called for an overhaul of U.S. ocean policy and management. Create a National Oceans Agency within the Executive Office of the President Create a National Oceans Agency within the Executive Office of the President Develop unified national policy. Develop unified national policy. Double federal budget for ocean research. Double federal budget for ocean research. 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.

MANAGING AND SUSTAINING MARINE FISHERIES  There are a number of ways to manage marine fisheries more sustainably and protect marine biodiversity.  Some fishing communities regulate fish harvests on their own and others work with the government to regulate them. Modern fisheries have weakened the ability of many coastal communities to regulate their own fisheries. Modern fisheries have weakened the ability of many coastal communities to regulate their own fisheries.

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, sea turtles, and bycatch fish 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 NON-NATIVE 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

PROTECTING, SUSTAINING, AND RESTORING WETLANDS The US has lost more than 50% of our original wetlands Figure 12-8

PROTECTING, SUSTAINING, AND RESTORING WETLANDS  Mitigation banking allows wetlands to be developed as long as an equal area of wetland is created or restored At least 50% of wetland mitigation projects fail At least 50% of wetland mitigation projects fail Mitigation has worked in Coastal Georgia salt marshes Mitigation has worked in Coastal Georgia salt marshes 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. 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. 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%. Runoff has caused noxious algal blooms in nearby coastal waters. Runoff has caused noxious algal blooms in nearby coastal waters.

Restoring the Florida Everglades  The the US Army Corps of Engineers 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.

Columbia River: Former (Future?) Salmon Habitat

PROTECTING, SUSTAINING, AND RESTORING LAKES AND RIVERS Sept-Dec In stream gravel Jan- April Emerge May-June A few months to 2 years Migrate to ocean in April- Aug Mature in ocean 2-5 yrs Migrate to “natal stream” Spawn Sept- Nov

PROTECTING, SUSTAINING, AND RESTORING LAKES AND RIVERS

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

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 (economic implications?) Removing hydroelectric dams will restore native spawning grounds (economic implications?)

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).

National Wild and Scenic Rivers Act  2% of US rivers remain free flowing  0.2% of US rivers are protected by the Wild and Scenic Rivers Act Smith River, CA Vermillion River, IL

National Wild and Scenic Rivers Act Skagit River, North Cascade Mountains, WA

National Wild and Scenic Rivers Act  Wild Rivers- untamed and inaccessible except by trail; no widening, straightening, dredging, filling, or damming; no motor boats allowed  Scenic Rivers- of great scenic value and accessible by a few roads; free of dams, mostly undeveloped; no motor boats allowed  Recreational Rivers- easily accessible; may have some dams or shore development; motor boats allowed.