Threats to marine biodiversity

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
Long line fishing
Lines with
hooks
Fish caught by
gills
Deep sea
aquaculture cage
Float Buoy

Biodiversity
• Variety of living things,
number of kinds
• Ecological diversity
– different habitats, niches,
species interactions
• Species diversity
– different kinds of
organisms, relationships
among species
• Genetic diversity
– different genes &
combinations of genes
within populations

Benefits of Biodiversity
• New food sources
– Grains, fruits, vegetables, meat, fish
4

Benefits of Biodiversity
• Medicines
• Plants
• Jellyfish & sea
anemones
• Nudibranchs
• Marine slugs
5

Biodiversity
• How much biodiversity
 1.7—2.0 million species
 Estimates to 100 million
6

Protecting Biodiversity
7
• How can we protect
biodiversity
– Stop overharvesting
• Sustainable yield
• Hunting & fishing laws
(every state ?)
– in developing nations ?
– Protect habitat
• Refuges, parks, preserves
– Endangered Species Act

Protecting Biodiversity
• Refuges, parks, preserves
– How big should refuges be?
– Where should they be?
– McArthur & Wilson “Theory of Island
Biogeography”
• colonization rate
• extinction rate (local)
• predicts number of species
8

Protecting Biodiversity
• Endangered Species Act (1973)
– Goal to “recover” species so they no longer need protection under ESA
– Implements U.S. participation in CITES
• “Convention on International Trade in Endangered Species”
• Prohibits trade in listed species
– whole organisms
– parts: skins, bones, teeth, flowers, leaves, etc.
• Other laws:
– Marine Mammal Protection Act
– Migratory Bird Treaty Act
– Anadromous Fish Conservation Act
– etc.
9

In broad terms, the living inhabitants of the marine realm face
five major threats:
• Changes to oceanic temperatures, acidity and
patterns of water movement (including
currents, eddies and fronts), largely caused by
increasing atmospheric carbon dioxide, as well
as impacts from damage to the ozone layer;
climate change:

• overfishing with attendant bycatch problems, both from
commercial fishing, recreational fishing, illegal unregulated
or unreported fishing (IUU), and ghost fishing.
• habitat damage largely caused by fishing gear, especially
bottom trawling, but also including the effects of coastal
development: destruction of coral reefs, mangroves,
natural freshwater flows (and passage), coastal foreshores,
coastal wetlands and sometimes entire estuaries – which
all support coastal marine ecosystems;
overfishing
habitat damage

• pollution (in-sea and land-based, diffuse and point source)
including nutrients, sediments, plastic litter, noise, hazardous
and radioactive substances; discarded fishing gear, microbial
pollution, and trace chemicals such as carcinogens, endocrine-
disruptors, and info-disruptors; and
• ecosystem alterations caused by the introduction of alien
organisms, especially those transported by vessel ballast water
and hull fouling.
pollution
ecosystem alterations

The core impacts of climate change
are caused by:
• An increase in the temperature of ocean
waters - causing, for example, coral bleaching
(Veron 2008);
• the increase in the acidity of ocean waters,
causing a rising aragonite saturation horizon,
particularly in the North Pacific and Southern
Ocean.

Important reviews of pollution in the
marine environment are provided by:
• Nutrients – a general review: Rabalais (2005– in the Caribbean:
• plastic litter – Derraik (2002); Goldberg (1997)
• noise –Firestone & Jarvis (2007); NRC (2005
• radioactive waste – Koslow (2007)
• heavy metals – Islam & Tanaka (2004)
• discarded fishing gear – Matsuoka et al. (2005); Brown (2007)
• microbial pollution – Islam & Tanaka (2004)
• endocrine disruptors –Porte et al. (2006)
• other hazardous materials – Islam & Tanaka (2004); Koslow (2007).

Threats to Marine Biodiversity
• Eutrophication
• Effects of contaminants
• Habitat degradation,
fragmentation and
destruction
• Fishing and especially
trawling
• Climate Change
Habitat Degradation

Reclamation (= coastal habitat destruction)
Threats to Marine Biodiversity

Threats to Marine Biodiversity;
Trawling

A full trawl
Picture from Greenpeace Web site
www.greenpeace.org
Threats to Marine
Biodiversity; Trawling
Above: Before Trawling;
Below: After Trawling

Important papers on marine and
estuarine habitat damage include:
• Estuaries and rivers – Ray (1996, 2004, 2005), Drinkwater & Frank
(1994);
• Impacts of bottom trawling –Gray et al. (2006), Jones (1992),
• Coral ecosystems – Aronson & Precht (2006), Jackson et al. (2001),
• mangroves – Duke et al. (2007), Ellison & Farnsworth (1996);
• seagrasses – Orth et al. (2006),
• kelp –Dayton et al. (1998).

Threats and controls:
Threats Controls
Overfishing
and bycatch
Restricted entry to fishery, catch quotas, limits or requirements
on gear, limits on fishing seasons, limits on fishing areas, no-
take areas, prohibitions on dumping or discarding gear.
Attempts to reduce or eliminate government subsidies
contributing to fishing over-capacity.
Control by flag States of high seas fishing particularly in regard
to compliance with international and regional fishing
agreements.
Market-based fishery accreditation systems such as that of the
Marine Stewardship Council.
Government control programs based on minimising ecosystem
effects
Surveillance and compliance programs including VMS.

Habitat
damage
Limits on gear, limits on fishing areas, no-take areas.
Fixed mooring systems in sensitive (eg coral)
environments. Surveillance and compliance programs.
Land-based zoning schemes combined with project
assessment and approval provisions aimed at minimising
the loss of coastal habitat resulting from land-based
developments. Special protection for high conservation
value estuaries. Zoning of key migration rivers to exclude
dams, weirs and other impediments to fish passage.
Protection of the catchment of high conservation value
estuaries and rivers to maintain natural water flows and
water quality.

Climate
change
International agreements, such as those focussed on greenhouse
gasses or chlorofluorocarbons or (eg: the Kyoto Protocol,
Montreal Protocol) - and the implementation programs which
follow, including incentives, prohibitions and market-based
schemes aimed at reducing GG emissions.
Pollution Controls focussed on fixed point sources, mobile point sources
and diffuse terrestrial sources – including dumping and
emissions to air and water . Controls on marine noise.
Controls focused on specific pollutants, such as plastics or
highly toxic or radio-active substances.
Integrated coastal and river basin planning, including objectives
to limit the passage of nutrients and other pollutants to the
marine environment.
Surveillance and compliance programs.

Biodiversity Hotspots
(Myers et al 2000 Nature)

Tropical cone snails contain toxins
which show promise for treating
some forms of cancer and heart
irregularities. One toxin may be a
thousand times more potent than
morphine for pain relief.
But millions of cone snails are now killed annually
for their shells, and their habitats are under pressure.
Cone snail from the Pacific
Ocean.
Biodiversity Losses = Loss of Services &
Potential Helpful Products

How can we prevent biodiversity loss?
•Research
•Legislation
•Education/Awareness
•Sustainable use of habitats
and fisheries
•Integration/Co-ordination

Marine Protection
Areas (MPA’s) are
used to…..
 Nationally / internationally
to conserve biodiversity.
 Manage natural resources.
 Protect endangered
species.
 Reduce user conflict.
 Provide educational and
research opportunities.
 Enhance commercial and
recreational activities.

Marine Protected
Areas
 Marine Protected
Areas are used as
management tools to
protect, maintain, or
restore natural and
cultural resources in
coastal and marine
waters.

Kinds of Marine
Protected Areas
1. National marine
sanctuaries.
2. Fishery management
zones.
3. National seashores.
4. National parks/
monuments.
5. Critical habitats.
6. National Wildlife refuges.
7. National estuarine research
reserves.
8. State conservation areas.
9. State reserves.

What do MPA’s protect?
Aggregations
Habitat important to
valuable fisheries
Sea Turtle nesting areas. Endangered Species

What do MPA’s
protect?
ShipwrecksCoral reef habitats

The End