Sustaining Aquatic Biodiversity. G. Tyler Miller’s Living in the Environment 13 th Edition Chapter 24. Key Concepts. Economic and ecological importance. Effects of human activities. Protecting and sustaining aquatic diversity. Protecting and sustaining fisheries.
G. Tyler Miller’s
Living in the Environment
Lake Victoria has lost its endemic fish species to large introduced predatory fish.
Reasons for Lake Victoria’s loss of biodiversity:
Introduction of Nile perch.
Loss of native cichlid species
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.
We know fairly little about the biodiversity of the world’s marine and freshwater systems.
The world’s marine and freshwater systems provide important ecological and economic services.
The most biologically diverse habitats include:
Deep ocean floor
Highest near the coast
25,000 known fish species
6% of total protein; 16% of animal protein
Medicines and Drugs
Antibiotics and anticancer drug, adhesives, bone reconstructive materials
seaweed, sponges, mollusks, coral barnacles, and other fish
Species loss and endangerment
Marine habitat loss and degradation
Freshwater habitat loss and degradation
Pollution and global warming
Freshwater species at greater risk
Mussels, crayfish, amphibians, fish
53% of coastal wetlands in US have disappeared
58% of world’s coral reefs are threatened
Warmer ocean temperatures
Two-thirds of US estuaries are at risk from pollution
35% of world’s mangroves have disappeared
The world has lost more than half of its inland wetlands
Agricultural and urban development
60% of the world’s larger rivers are fragmented by dams, diversions, and canals
Flood control levees and dikes
Alter and destroy aquatic habitats
Disconnect rivers from their floodplains
Eliminate wetlands and backwaters (spawning areas)
75% of the world’s 200 commercially valuable marine fish species are overfished
Overfishing leads to commercial extinction
Depletions and extinction of species unintentionally caught as bycatch
Deliberate or accidental introduction into coastal waters, lakes and wetlands
Asian swamp eel
Displace or cause extinction of native species
68% of fish extinctions
Major pollution threats
Sediment and soil erosion
Global warming could
alter migration and feeding patterns
increase ocean temperature
raise sea levels
Six of the world’s seven major turtle species are threatened or endangered because o human activities.
Example: Sea turtle
Turtle extrusion devices (TEDs)
Shrimp trawler Victoria
Turtle Extrusion Device
Area enlarged right
Manatee can eat unwanted Water Hyacinths.
Endangered due to:
Entanglement from fishing lines and nets.
Hit by speed boats.
Stress from cold.
Low reproductive rate
After many of the world’s whale species were over-harvested, commercial whaling was banned in 1960, but the ban may be overturned.
Despite ban, Japan, Norway, and Iceland kill about 1,300 whales of certain species for “scientific purposes”.
Although meat is still sold commercially.
Identifying and protecting endangered and threatened species
Turtle extrusion devices (TEDs)
National and International laws and treaties
CITES - Convention on International Trade and Endangered Species
Global Treaty on Migratory Species
US Marine Mammal Protection Act
US Endangered Species Act
US Whale Conservation and Protection Act
International Convention on Biological Diversity
Establish marine protected areas
Coastal nations have sovereignty over waters and seabeds up to 12 miles offshore
Jurisdiction over their Exclusive Economic Zone extends 200 miles offshore
Integrated coastal management
community based attempt to develop and use coastal resources sustainably
Regulating and preventing ocean pollution
Sustaining management of marine fisheries
Set, monitor, and enforce fishery catch limits below estimated MSY (maximum sustained yield)
Divide up fishing quotas
Require selective gear
Improve monitoring and enforcement
Reduce or eliminate subsidies
Impose fees for harvesting fish and shellfish from public managed offshore waters
Certify sustainable fisheries
Wider mesh fish nets
Observers on boats
Multiple species licensing
Laws prohibiting throwing edible and marketable fish back to sea
Establish no-fishing marine areas
Protect marine habitats that are in good condition and disregard potentially hopeless cases
Strengthen commitment to marine biodiversity protection
Kill organisms in ship ballast water
Develop filters and traps
Require ships to dump ballast water beyond 200 mile limit
Use labeling to identify fish that have been harvested sustainably
Restrict location of fish farms to reduce loss of mangrove forests
Enact and enforce stricter pollution regulations
Increase productions of herbivorous aquaculture fish species
federal permit required
allows destruction of existing wetlands if an equal area of they same type of wetland is created or restored
Land use planning
steer agriculture and mining away from wetlands
often has limited success
Control of invasive species
Natural flow of the Everglades has been diverted or disrupted.
Farmers planted vast agricultural land to sugarcane and vegetables.
Established Everglades National Park. Became the most endangered park.
Massive plumbing and land development projects cut off water flow
1990 began the world’s largest ecological restoration project.
restore he curving flow of more than half of the Kissimmee River.
remove 400 km of canals and levees
create artificial marshes in previous farmland
add land adjacent to Everglades National Park
create network of artificial marshes
create 18 large reservoirs
capture much of the water flowing out to sea and return it to the Everglades
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).