820 likes | 834 Views
Explore the success story of protecting whales from commercial extinction, the threats they face, and the vital role of aquatic biodiversity in marine ecosystems. Discover the impact of human activities, invasive species, pollution, and climate change on cetaceans, with a focus on sustainable conservation efforts.
E N D
Chapter 11 Sustaining Aquatic Biodiversity
Case Study: Protecting Whales: A Success Story… So Far • Cetaceans: Toothed whales and baleen whales • 8 of 11 major species hunted to commercial extinction by 1975 • 1946: International Whaling Commission (IWC) • Set quotas for whale species to prevent overharvesting • Quotas based on insufficient data • Quotas often ignored
Case Study: Protecting Whales: A Success Story… So Far • 1970: U.S. • Stopped all commercial whaling • Banned all imports of whale products • 1986: IWC moratorium on commercial whaling • Moratorium- suspension of activity • 42,480 whales killed in 1970 • 1500 killed in 2009 • Norway, Japan, and Iceland ignore moratorium
Examples of Cetaceans Fig. 11-1, p. 250
Toothed whales Sperm whale with squid Killer whale (orca) Bottlenose dolphin Baleen whales Blue whale Fin whale Humpback whale Minke whale 0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 Fig. 11-1, p. 250 Meters
Baleen whales Toothed whales Sperm whale with squid Blue whale Killer whale Narwhal Fin whale Bottlenose dolphin Bowhead whale 0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 Meters Right whale Sei whale Humpback whale Gray whale Minke whale 0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 Meters Stepped Art Fig. 11-1, p. 250
11-1 What Are the Major Threats to Aquatic Biodiversity? • Concept 11-1 Aquatic species are threatened by habitat loss, invasive species, pollution, climate change, and overexploitation, all made worse by the growth of the human population.
We Have Much to Learn about Aquatic Biodiversity • Greatest marine biodiversity • Coral reefs • Estuaries • Deep-ocean floor • Biodiversity is higher • Near the coast than in the open sea • In the bottom region of the ocean than the surface region • Deepest parts of the ocean are the least explored • Where sunlight does not penetrate • Scientists, internationally, working on exploration projects
Natural Capital: Marine Ecosystems Fig. 8-5, p. 172
Natural Capital Marine Ecosystems Ecological Services Economic Services Climate moderation Food CO 2 absorption Animal and pet feed Pharmaceuticals Nutrient cycling Harbors and transportation routes Waste treatment Reduced storm impact (mangroves, barrier islands, coastal wetlands) Coastal habitats for humans Recreation Habitats and nursery areas Employment Oil and natural gas Genetic resources and biodiversity Minerals Building materials Scientific information Fig. 8-5, p. 172
Natural Capital: Freshwater Systems Fig. 8-15, p. 181
Natural Capital Freshwater Systems Ecological Services Economic Services Climate moderation Food Nutrient cycling Drinking water Waste treatment Irrigation water Flood control Groundwater recharge Hydroelectricity Habitats for many species Transportation corridors Genetic resources and biodiversity Recreation Scientific information Employment Fig. 8-15, p. 181
Human Activities Are Destroying and Degrading Aquatic Habitats • Marine • Coral reefs • Mangrove forests • Seagrass beds- nurseries • Sea-level rise from global warming will harm coral reefs and low-lying islands with mangrove forests • Ocean floor: effect of trawlers • Freshwater • Dams • Excessive water withdrawal
Natural Capital Degradation: Area of Ocean Bottom Before and After a Trawler Fig. 11-2, p. 252
Invasive Species Are Degrading Aquatic Biodiversity • Invasive species • Problem 1: Threaten native species • Problem 2: Disrupt and degrade whole ecosystems • Many aquatic invaders come from ballast water transport • Two examples • Asian swamp eel: waterways of south Florida • Most likely dumped from home aquariums • Eats nearly anything; evades environmental stress by burrowing into mud banks • Lionfish in the Atlantic • Believed to escape form home aquariums after hurricane Andrew in Miami
Invasive Lionfish Fig. 11-3, p. 254
Case Study: Invaders Have Ravaged Lake Victoria • Loss of biodiversity and cichlids (200 species now extinct) • Nile perch: deliberately introduced • Devoured cichlids • Perch-fishing industry economically hurt small-scale fishers • Frequent algal blooms • Nutrient runoff • Spills of untreated sewage • Less algae-eating cichlids • Water hyacinths- another invasive plant species
Natural Capital Degradation: The Nile Perch In Lake Victoria Fig. 11-4a, p. 254
Water Hyacinths in Lake Victoria Fig. 11-5, p. 255
Population Growth and Pollution Can Reduce Aquatic Biodiversity • More noise and crowding from humans • Nitrates and phosphates, mainly from fertilizers, enter water • Leads to eutrophication • Fish die-offs • Toxic pollutants from industrial and urban areas • Irrwaddy dolphins: DDT, PCBs, Mercury poisoning • Plastics • Ingestion by birds and other wildlife
Hawaiian Monk Seal Fig. 11-6, p. 256
Climate Change Is a Growing Threat • Global warming: sea levels will rise and aquatic biodiversity is threatened • Coral reefs • Swamp some low-lying islands • Drown many highly productive coastal wetlands • New Orleans, Louisiana, and New York City
Overfishing and Extinction: Gone Fishing, Fish Gone • Fishery: concentration of a particular wild aquatic species suitable for commercial harvesting in a specific area • Fishprint: area of ocean needed to sustain the fish consumption of a person, country, or the world • Marine and freshwater fish • Threatened with extinction by human activities more than any other group of species
Overfishing and Extinction: Gone Fishing, Fish Gone • Commercial extinction: no longer economically feasible to harvest a species • Fewer larger fish (tuna, cod, marlin, swordfish) means: • More problems with invasive species • Rapidly reproducing; jelly-fish burgers • Shift to exploiting smaller fish species
Natural Capital Degradation: Collapse of the Cod Fishery Off the Canadian Coast Fig. 11-7, p. 257
900,000 800,000 700,000 600,000 500,000 Fish landings (tons) 400,000 1992 300,000 200,000 100,000 0 1900 1920 1940 1960 1980 2000 Year Fig. 11-7, p. 257
Case Study: Industrial Fish Harvesting Methods • Trawler fishing • Via weighted net; used mostly for fishes and shellfish • Scrape bottom of ocean floor • Purse-seine fishing • large net to catch surface fish; help from spotter plane • Longlining • Long line of baited hooks • Adjusted to catch different open-ocean species • Drift-net fishing • Bycatch problem
Major Commercial Fishing Methods Used to Harvest Various Marine Species Fig. 11-8, p. 259
Fish farming in cage Trawler fishing Spotter airplane Purse-seine fishing Sonar Drift-net fishing Long line fishing Float Buoy lines with hooks Deep sea aquaculture cage Fish caught by gills Fig. 11-8, p. 259
Trawler fishing Sonar Drift-net fishing Long line fishing Float Buoy lines with hooks Fish caught by gills Fish farming in cage Spotter airplane Purse-seine fishing Deep sea aquaculture cage Stepped Art Fig. 11-8, p. 259
11-2 How Can We Protect and Sustain Marine Biodiversity? • Concept 11-2 We can help to sustain marine biodiversity by using laws and economic incentives to protect species, setting aside marine reserves to protect ecosystems, and using community-based integrated coastal management.
How can we Protect and Sustain Marine Biodiversity? • Treaties/Laws • Economic Incentives • Marine reserves and protected areas • Restoration • Indivisuals and communities commitment • Take note on each approach
Protecting and Sustaining Marine Biodiversity • Protecting marine biodiversity is difficult because • Much of the damage in not visible • Resources of the ocean viewed as inexhaustible • Most of the world’s oceans lies outside of legal jurisdictions so it is subject to over exploitation --tragedy
Laws and Treaties- Species Approach • Convention on International Trade in Endangered Species (CITES) • Global Treaty on Migratory Species • U.S Marine Mammal Protection Act • U.S. Endangered Species Act • U.S. Whale Conservation and Protection Act **Know what the goal of Each of these are
Protecting and Sustaining Marine Biodiversity • 3 of 8 major sea turtle species are endangered and the rest are threatened • Degradation of beach habitat where they lay eggs, legal and illegal taking of eggs • Increased use as a food, medical ingredient, jewelry, and leather • Unintentionally captured and drowned by commercial fisherman – as many as 40,000/yr • Turtle exclusion devices have saved 1000’s of turtles from shrimp trawlers.
TED- turtle exclusion device Turtle ejected here Shrimp end up here
Case Study: Whaling • Commercial Whaling (Cetaceans) • Easy to kill because of their large size and need to come to surface to breathe • Mass slaughter increased with the use of radar and airplane to locate the whales • 1.5 million whales killed between 1925 and 1975 • 8 of 11 major species became commercially extinct and the blue whale to the point of biological extinction
Protecting and Sustaining Marine Biodiversity • The International Whaling Commission (IWC) was established in 1946 to regulate the whaling industry by setting annual quotas • Did not work • IWC quotas were based on inadequate data or ignored by whaling countries • IWC did not have power of enforcement • In 1970, The U.S. stopped all whaling and banned the import of all whale products • In 1986, the IWC has imposed a moratorium on whaling. Whales killed dropped from 42,480 in 1970 to 1,200 in 2004
Protecting and Sustaining Marine Biodiversity • Norway and Japan continue to hunt certain species and Iceland resumed hunting in 2002 • Japan, Norway, Iceland, Russia, and a number of small tropical islands are working towards overthrowing the IWC whaling ban • A traditional part of the economies and culture of some countries • Believe ban is based on emotion not updated scientific estimates of whale populations • Eskimos still allowed to whale
0 5 10 15 20 25 30m 0 10 20 30 40 50 60 70 80 90 100ft Atlantic white-sided dolphin Common dolphin Harbor porpoise Killer whale Bottlenose dolphin Beluga whale False killer whale Cuvier's beaked whale Pilot whale Narwhal Pygmy sperm whale Sperm whale Baird's beaked whale Squid Odontocetes (Toothed Whales)
Protecting & Sustaining Marine Biodiversity using economic incentives • Example: Sea Turtles • More valuable alive than dead • Sea turtle-tourism brings in 3x more $$ than sale of turtle products
Protecting and Sustaining Marine Biodiversity • The UN Law of the Sea- • All coastal nations have sovereignty over the waters 12 miles offshore • Jurisdiction over their Exclusive Economic Zone, which stretches 200 miles offshore • The rest is high seas • Control over 36% of the ocean and 90% of the fish stock yet the oceans are still over fished • World Conservation Union (IUCN) since 1986, has helped develop a global system of Marine Protected Areas (MPAs) • Protected from all or most of human activities • 1,700 existing MPAs protect about 0.2% of ocean area
Protecting and Sustaining Marine Biodiversity • Marine Reserves- no take or fully protected MPAs. • No extraction or alteration of living or nonliving resources is allowed • Australia has the largest • Results?-- Fish populations double, fish sizes grow by one-third, fish reproduction triples, and species diversity grows by almost one-fourth in 2-4 years • Less than 0.01% of the world’s ocean and 50 square miles in U.S. are in marine reserves
Protecting and Sustaining Marine Biodiversity-individual and communities commitment • Integrated coastal management is community-based efforts to develop and use coastal resources more sustainably • Develop workable, cost effective, adaptable solutions that preserve biodiversity and still meet economic and social needs • Zone areas to include fully protected marine reserves and other zones where different levels of human activities are permitted • 90 coastal counties in the U.S. are working to establish integrated coastal management zones with 20 of them fully implemented
Ecosystem Approach vs Species Approach • Ecosystem approachfocuses on protecting whole marine ecosystems rather than individual species protection • MPAs • Marine Reserves • Reconciliation ecology (restoration)
Restoration Ecology • http://www.clickorlando.com/Making-a-Difference-Restoring-oyster-beds/-/1637238/20689372/-/13xg195z/-/index.html
Managing and Sustaining Marine Fisheries • 1st step: Estimate and monitor fishery population • Difficult to do, yet essential to attempt • Cooperation and regulation (Catch-Share Policies) • Reduce/eliminate government subsidies • Promote sustainable consumer choices
Managing and Sustaining The World’s Marine Fisheries • World commercial fishing has been managed by maximum sustained yield (MSY)-the maximum number of fish that can be harvested from a fish stock without causing a population drop. • Hasn’t worked • Fish stock difficult to measure and based on unreliable and underreported catch • Populations of other target and other non-target fish species and marine organisms also affected • Quotas are difficult to enforce