Importance of Aquatic Ecosystems Why is preserving these ecosystems important? What services do they provide to other ecosystems, organisms, or humans? What are ways that humans are threatening these ecosystems? (specific ways)

Threats to Aquatic Ecosystems Chapter 11

Human Impacts on Biodiversity Specific threats to Aquatic Biodiversity Pollution (non-point and point source) Degradation of coastal/inland wetlands and estuaries Overfishing Invasive species Altering lake/river flow—dams and irrigation Climate change Ocean Habitat destruction (ocean bottom and coral reefs)

Threats to Aquatic Biodiversity… and biodiversity in general HIPPCO H-Habitat Loss and Degradation I- Invasive Species P- Human Population Growth P- Pollution C- Climate Change O- Overexploitation

HIPPCO Habitat Loss and Degradation little is understood about the ocean and its organisms 90% of all fish species spawn on coral reefs, coastal wetlands and marshes, in mangrove forests, and rivers. these are among the most threatened aquatic ecosystems Sea grass beds (which act as nurseries) are being lost or degraded Rising sea levels (due to climate change) will destroy reefs and swamp coastal wetlands Sea bottom habitats destroyed due to harmful fishing practices (trawling/dredging) In freshwater ecosystems... dams alter river flows irrigation for agriculture provides enormous stress on water resources

HIPPCO Invasive Species introduced deliberately or accidentally displace or cause the extinction of native species and disrupt ecosystem functioning most have arrived in ship ballast water (globalization)

HIPPCO Human Population Growth majority of the worlds population lives in coastal areas, this increase has added additional pressure to these ecosystems oceans becoming more crowded (collisions with whales and ships) oceans becoming noisier (disrupt communication and migration patterns)

HIPPCO Pollution most comes from land-based activities run-off of nitrogen and phosphorus fertilizers increase eutrophication and cause algal blooms toxic chemicals (DDT, PCBs, mercury)from industry can kill aquatic species or alter their physiology Plastic. Mimic food sources and are accidentally ingested. Release toxic compounds to the water.

HIPPCO Climate Change Rising sea levels destroy reefs, wetlands, and other ecosystems displace humans to other areas Warmer and more acidic water. increases dissolved CO2, breaks down shells of organisms

HIPPCO Overexploitation Overfishing. Industrial fishing fleets include ~4 million boats currently harvesting 57% more than the sustainable yield “Commercial Extinction”--no longer profitable to continue harvesting the species If given time, fisheries can recover quickly, but if continued to be exploited then less likely to bounce back. larger fish species (tuna, cod, marlin, swordfish) are increasingly scarce...so begin to fish “down the food chain” which provides less food for larger species

Too many boats, chasing too few fish….

Fishery: concentration of a particular wild aquatic species suitable for commercial harvesting Fishprint: defined area of ocean needed to sustain the fish consumption of an average person, nation, or world. Bycatch: unwanted, accidentally caught organisms that are thrown back (33% of total catch) 20 million metric tons are destroyed a year 80,000 whales, dolphins, seals, and turtles are among the animals Shrimp trawlers throw back 5.2 pounds of marine life that will eventually die for every pound of shrimp caught

As fisheries continue to be exploited their recovery time increases Commercially valuable wild species (cod, tuna, marlin, swordfish, mackerel, even sharks) will be driven to extinction if continued to be harvested at current rates. Some estimate as soon as 2050! Aquatic species are disappearing 5 times faster than terrestrial ones Example: Atlantic Cod off the coast of Newfoundland Species was hunted to brink of extinction. Ban on fishing was implemented in early 1990s. Populations have still not recovered. (Tragedy of the Commons!)

Industrial Fishing Practices Modern fishing boats are very sophisticated using GPS, sonar, spotter planes, large nets and long fishing lines to find the fish. Essentially the fish have no chance to hide… Cause tremendous ecosystem damage and reduce biodiversity A large portion of the fishing vessels come from less- developed countries (especially Asia) Many which don’t abide by international fishing quotas

Trawling Used to catch cod, flounder, shrimp and scallops Drag a funnel shaped net along the ocean bottom, weighted with chains and plates Some nets large enough to hold s!! VERY destructive. Destroys everything in its path Same as clear cutting a forest

Purse-Seine Used to catch surface dwelling species (tuna, mackerel, anchovies, salmon and herring), schooling species A large net encloses the school, tightens around it then brings fish to the boat

Long-Line Lines up to 60 miles long with thousands of baited hooks Depth of line adjusted to catch open-ocean species (swordfish, tuna, shark) or ocean-bottom species (halibut and cod) Accidently catch sea turtles, birds, and dolphins on hooks

Driftnet (gill net) Drifting nets go as deep as 50 feet and 40 miles long Leads to unwanted fish caught as well as overfishing of certain species Accidentally catch mammals, turtles,and bird Lines longer than 1.2 miles banned by the UN in 1992 in international waters Compliance is voluntary!

Whaling Industry During the height of the whaling industry 1.5 million whales were killed ( ) Drove 8 of the 11 major species to commercial extinction Right, bowhead, blue, fin, sei, humpback, minke and sperm whales Blue whale numbers (largest mammal) are less than International Whaling Commission was established to regulate industry 1986 set moratorium on whaling (banned) including the sale of whale products Iceland (minke, fin) Japan (minke, sei and fin), and Norway (minke) ignore ban

Fisheries Management Difficult to estimate fish numbers due to size of ecosystem and migration Aim for harvesting “optimum sustained yield” Set quotas and fishing allotment (fishing seasons) Decrease government subsidies on fish Consumer vote (buy sustainably harvested fish) Marine Stewardship Council Labels Ask where fish came from Protect predator species (eat lower on food chain) Aquaculture “farming fish” Presents a new set of problems…

Protecting and Sustaining Aquatic Biodiversity

Difficult to protect aquatic ecosystems due to rapidly growing human population and expanding ecological footprint Damage isn’t always visible Historically have believed ocean is an inexhaustible resource Ocean lies outside the legal jurisdiction of any country— or have rivers/lakes that span multiple countries Leads to overexploitation (Tragedy of the Commons) Challenges…

Laws and Treaties Convention on the International Trade in Endangered Species Ensures trade of organisms doesn’t harm their survival (endangered and threatened species) 1979 Global Treaty on Migratory Species Protects migration routes and habitat for terrestrial, aquatic and avian species (UN) 1972 Marine Mammal Protection Act Listed organisms may not be “taken” in US waters or high seas or their products imported US Endangered Species Act Lists and protects endangered species and their habitats

1976- US Whale Conservation and Protection Act Protects whales along US coasts including Mexico and Canada; prohibits sale of whale products (including imports) International Convention on Biological Diversity Develop strategies to sustain and protect biodiversity on a global level International Moratorium on Whaling Globally prohibits the hunting of whales and selling of whale products **All of these are difficult to enforce international compliance

Marine Ecosystems Economic Incentives to Protect Species (ecotourism) Animals worth more alive than dead Marine Sanctuaries Countries allocate offshore fishing zones (it regulates up to 200 nautical miles from shoreline) Boats may only fish here with permission “high seas”- ocean area beyond any legal jurisdiction (difficult to monitor and enforce) “Law of the Sea Treaty” Outlines who can fish where Need to switch focus to protecting ecosystems, not just individual species Less than 1% of the ocean currently protected in marine reserves, recommended to protect 30-50%

Freshwater Ecosystems Wetlands Develop land areas away from them Permit required to fill in more than 3 acres Only 6% of remaining wetlands protected “mitigation banking”—may destroy wetlands as long as recreate the same size in another area (not always effective) Lakes and Rivers 1968 Wild and Scenic Rivers Act—protects only 3% of US rivers Preserve rivers in their natural “free-flowing” state Minimize exposure to invasive species, or work to remove those already present Protect watersheds Identify pollutant sources Damming rivers causes ecosystem disruption Prevent fish species from spawning