ch 13 sustaining aquatic biodiversity. overview of aquatic biodiversity world oceans cover 71% of...

Ch 13Sustaining Aquatic

Biodiversity

Overview of Aquatic Biodiversity World oceans cover 71% of the planet’s surface

63% of known fish species exist in marine systems 37% live in freshwater systems

Humans have only explored 5% of the earth’s global ocean

Ecological and economical benefits could result from further scientific study of poorly understood marine and freshwater systems.

Life As We Know It- 9min

Overview of Aquatic Biodiversity 2003 – Pew Commission found U.S. coastal waters

were in trouble and laws protecting them needed reforming

Commissions recommendations: Double the federal $ for ocean research Base fisheries management on preserving aquatic

ecosystems and habitats rather than catch limits Set up a systems of marine reserves

The Magnuson-Stevens Act- passed in 2007 which mandates annual catch limits and accountability measures and calls for international cooperation.

Overview of Aquatic Biodiversity Coral reefs, estuaries, and the ocean bottom

contain the greatest marine biodiversity Greater variety of producers, habitats, food sources and

nurseries Biodiversity is higher near coastlines than open ocean Benthic (bottom) regions have greater biodiversity than

surface regions Lowest diversity is the middle region of the open

ocean 6% of our total protein and 20% of our animal

protein comes from marine fish and shellfish—potentially renewable resource.

Human Impacts on Aquatic Biodiversity

Greatest threat is loss and degradation of habitats 1/2 of world’s coastal wetlands

lost during the last century 25% of world’s coral reefs

severely damaged, mostly by humans

1/3 of world’s original mangrove forests have disappeared, mostly due to clearing for development

Bottom habitats are being degraded and destroyed by dredging and trawler boat activity

Bleached Brain Coral

Factory encroaching on wetlands


3/4 of the world’s 200 commercially valuable fish are either overfished or fished to their estimated sustainable yield. Overfishing leads to commercial extinction

Modern fishing methods could cause 80% depletion in only 10-15 years

Large fish in many commercially valuable species are becoming scarce

Study showed in the last 45 yrs the abundance of large open ocean fish like tuna and bottom-dwelling fish like cod have fallen 90%


After large species are disrupted, the fishing industry works its way down the food chain to smaller fish disrupting the food chain further

One-third of the annual fish catch is thrown overboard dead or dying as bycatch (nontarget species)


1200 marine species have become extinct in the past several hundred years

Fish are more threatened with extinction by human activity than any other animal

37% of the known freshwater fish in the U.S and 20% of the 10,000 freshwater fish in the world are threatened with extinction or are already extinct (UN Food and Agriculture Organization)

Blue (Prionace glauca) and Mako shark fins at a shark finning camp, Magdalena Bay, Baja California, Mexico.


Deliberate or accidental introduction of nonnative species into coastal waterways, wetlands, and lakes cost the U.S. about $16 million per hour

Purple loosestrife was imported into the U.S. in the 1880’s as an ornamental plant. Released in ballast water Single plant can produce 2.5

million seeds/yr Native plants cannot compete State have begun to introduce a

weevil species and a leaf-eating beetle. Will they become pests?

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


Protecting marine biodiversity is the same as protecting terrestrial biodiversity; identifying and protecting threatened and endangered species and their habitats

A California Sea Lion entangled in a fishing net that is slowly killing it.

Major commercial fishing methods. Modern methods enable increasing harvest of decreasing populations.

Case Studies: Commercial Fishing and Sea Turtles


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.

Shrimp end up here

Turtle ejected 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


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


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

Atlanticwhite-sideddolphin

Harborporpoise

Commondolphin

Killerwhale

Belugawhale

Bottlenosedolphin

False killerwhale

Pilotwhale

Cuvier'sbeakedwhale

Pygmyspermwhale

Spermwhale

Narwhal

Squid

Baird'sbeakedwhale

Odontocetes (Toothed Whales)

0 5 10 15 20 25 30m

0 10 20 30 40 50 60 70 80 90 100ft


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


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


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

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

Managing and Sustaining The World’s Marine

Fisheries

Managing and Sustaining The World’s Marine Fisheries

**Optimum sustained yield (OSY) -takes into account interactions with other species to provide more room for error

Multi-species management takes into account the competitive and predator-prey relationships of a number of interacting species

Proposed Catch Share Policy

2009 Obama stated his administration’s commitment to creating comprehensive protective measure for our national fisheries and other oceanic wildlife.

NOAA Catch Share Policy has been drafted Uses several fishery management

strategies to allocate portions of the fishery catch to individuals, cooperatives, communities, etc.

Rebuild and sustain fisheries Must stop fishing when their quota is

reached Prevents “race for the fish”

Protecting, Sustaining, and Restoring Wetlands

Coastal and inland wetland are areas of tremendous aquatic biodiversity

Federal permits required to fill in 3 or more acres of wetlands Cut average wetland loss by

80% between 1969 and 2002 8% of remaining wetland are under federal control Mitigation banking allows destroying existing

wetlands in exchange for creation of artificial wetlands in another area.

50% of created wetlands fail or do not replace the ecological functions of the natural wetlands

Protecting, Sustaining, and Restoring Lakes and Rivers

Great Lakes are the world’s largest body of fresh water They have been invaded by 162 nonnative species since

1920. Most have arrive in the bilge water of ships Sea lampreys Zebra mussels Asian carp – to reach the lakes soon

Nonnative species are their greatest threat.


Rivers and streams provide important ecological and economic services Can be disrupted by

over fishing, pollution, dams, and water withdrawal for irrigation

Lakes much more vulnerable than rivers. Why?

Case Study: Columbia River Columbia River

World’s largest hydroelectric power system

Irrigation for agricultural land Water source for major municipal

areas Salmon blocked from migrating

upstream to lay their eggs due to dams disrupting rivers

Salmon needs trees along the river to keep water cool enough for the eggs to survive and to keep silt from covering them

Solutions

Rebuilding Salmon Populations

Building upstream hatcheries

Releasing juvenile salmon from hatcheries to underpopulated streams

Releasing extra water from dams to wash juvenile salmon downstream

Building fish ladders so adult salmon can bypass dams during upstream migration

Using trucks and barges to transport salmon around dams

Reducing silt runoff from logging roads above salmon spawning streams

Banning dams from some stream areas


Salmon Ranching has taken the place of wild salmon spawning Salmon eggs and young are raised in hatcheries and

released into the wildcompetition Reduces the genetic diversity of the wild salmon Environmental stress after fish release

Fish change form

Fish enter riversand head forspawning areas

Grow to smoltand enter the ocean...

Grow to maturityin Pacific Oceanin 1-2 years

Eggs and young arecared for in the hatchery

Fry hatch in the spring...

Fingerlings migrate downstream

In the fall spawning salmondeposit eggs in gravel nests and die

NormalLifeCycle

Fingerlingsare released into river

And grow in the streamfor 1-2 years

Human capture

Salmonprocessingplant

Eggs are taken from adultfemales and fertilized withsperm “milked” from males

ModifiedLifeCycle

To hatchery


1968, National Wild and Scenic Rivers Act- protects rivers and river segments with outstanding scenic, recreational, geological, wildlife, historical or cultural value Wild rivers may not be widened, straightened,

dammed, filled, or dredged. Swimming, camping, nonmotorized boating, sport

hunting, and fishing are permitted Scenic rivers are not dammed, mostly

undeveloped, accessible by road in some areas and of great scenic value

Recreational rivers are readily accessible by roads and have some development along their shores

Natural Capital

Ecological Services of Rivers

•Deliver nutrients to sea to help sustain coastal fisheries

•Deposit silt that maintains details

•Purify water

•Renew and renourish wetlands

•Provide habitats for wildlife

ch 13 sustaining aquatic biodiversity. overview of aquatic biodiversity world oceans cover 71% of...

Documents

marine fish

greater biodiversity

years fish

valuable fish

nurseries biodiversity

known fish species

smaller fish

dwelling fish