SUSTAINABILITY & AQUACULTURE

ECASA STAKEHOLDER MEETINGHERAKLION, 18-19 SEPTEMBER 2007

Paul Tett

ECASA

• Ecosystem Approach to Sustainable Aquaculture

What's in this talk?

• Ecosystem approach, sustainability

• Systems and ecosystems

• Ecosystem state, status and health

• Management for sustainability

What's in this talk?

• Ecosystem approach, sustainability

• Systems and ecosystems

• Ecosystem state, status and health

• Management for sustainability

(some key ideas for understanding what ECASA has done and what its toolbox can offer)

Sustainability

Ecosystem approach

Ecosystem approach• "The Ecosystem Approach, as defined by the Convention

on Biological Diversity is “a strategy for the integrated management of land, water and living resources that promotes conservation and sustainable use in an equitable way”."

Ecosystem approach• "The Ecosystem Approach, as defined by the Convention

on Biological Diversity is “a strategy for the integrated management of land, water and living resources that promotes conservation and sustainable use in an equitable way”."

• "Daoists view morality in medical terms: goodness consists of the optimal health of a system comprised of various interdependent subsystems. This medical concept of virtue can ... be useful in constructing an ecological ethics, one that recognizes that humans cannot act for their own good without considering the overall health of the ecosystems in which they are embedded. ... the ideal state is achieved through embodying the complex transformative power of nature rather than denying it." [Miller, J. (2006). Daoism

and Nature. In Handbook of Religion and Ecology (ed R. Gottlieb), Oxford University Press. (my underlining)]

Ecosystem approach - another view

• Rime of the Ancient Mariner, by Coleridge (1798)

... He prayeth well, who loveth well

Both man and bird and beast.

He prayeth best, who loveth best

All things both great and small;

For the dear God who loveth us

He made and loveth all.

Ecosystem approach - another view

• Rime of the Ancient Mariner, by Coleridge (1798)

... He prayeth well, who loveth well

Both man and bird and beast.

He prayeth best, who loveth best

All things both great and small;

For the dear God who loveth us

He made and loveth all.

we are all in the same boat!

to be: Sustainable to be: Sustainable• Leave the world (and its natural resources) the way

that you found it - so that your grandchildren (and other peoples' grandchildren) will be no worse off than we are now [some economists disagree - they think that resources are infinitely replaceable]

to be: Sustainable• Leave the world (and its natural resources) the way

that you found it - so that your grandchildren (and other peoples' grandchildren) will be no worse off than we are now [some economists disagree - they think that resources are infinitely replaceable]

• Treat your farm site so that it continues to return to you an income [depending on market conditions - and sometimes it appears cost-effective to harm the site in order to maximize income]

to be: Sustainable• Leave the world (and its natural resources) the way

that you found it - so that your grandchildren (and other peoples' grandchildren) will be no worse off than we are now [some economists disagree - they think that resources are infinitely replaceable]

• Treat your farm site so that it continues to return to you an income [depending on market conditions - and sometimes it appears cost-effective to harm the site in order to maximize income]

• Maintain a healthy ecosystem at your farm site, and in the water body or region containing an aquacultural industry [partly enforced by the Water Framework Directive]

System & Ecosystem

Systems ... are a way of

looking at things

''Systems in many respects resemble machines. A machine is a little system, created to perform, as well

as to connect together, in reality, those different movements and effects which the [maker] has

occasion for. A system is an imaginary machine, invented to connect together in the fancy those

different movements and effects which are already in reality performed.''

Adam Smith's essay on `Astronomy' in Essays on Philosophical Subjects, 1795, and quoted from the Introduction by A.Skinner to Smith's The Wealth of Nations, Penguin Books, London, 1986 reprint; the word 'maker', here, replaces 'artist'

in the original.}

Ecosystem''any area of nature that includes living organisms

and nonliving substances interacting to produce an exchange of materials between the living and

nonliving parts is an ecosystem''Odum, E.P. (1959) Fundamentals of Ecology.

Ecosystem''any area of nature that includes living organisms

and nonliving substances interacting to produce an exchange of materials between the living and

nonliving parts is an ecosystem''Odum, E.P. (1959) Fundamentals of Ecology.

• components - living and nonliving things, interacting together

• interaction networks include self-stabilizing feedback loops: the emergent property of ecosystem health = ability to resist pressure

• definable boundaries (!'scale')

Ecosystem''any area of nature that includes living organisms

and nonliving substances interacting to produce an exchange of materials between the living and

nonliving parts is an ecosystem''Odum, E.P. (1959) Fundamentals of Ecology.

• components - living and nonliving things, interacting together

• interaction networks include self-stabilizing feedback loops: the emergent property of ecosystem health = ability to resist pressure

• definable boundaries (!'scale')

Ecosystem of Loch Creran: a real place as well as an idea

Ecosystem''any area of nature that includes living organisms

and nonliving substances interacting to produce an exchange of materials between the living and

nonliving parts is an ecosystem''Odum, E.P. (1959) Fundamentals of Ecology.

• components - living and nonliving things, interacting together

• interaction networks include self-stabilizing feedback loops: the emergent property of ecosystem health = ability to resist pressure

• definable boundaries (!'scale')

Ecosystem of Loch Creran: a real place as well as an idea

Creran's ecosystem boundaries

Humans: partly in and partly outside the ecosystem

boundary

conditions

ecosystem

socio-economic

system

humans

ME

ME

MEmass-energy flow

information (including !) flow

Humans: partly in and partly outside the ecosystem

boundary

conditions

ecosystem

socio-economic

system

humans

ME

ME

ME

farm

mass-energy flow

information (including !) flow

Some of the environmental problems

resuspension

oxygen demand

phytoplankton

nutrients

sinking organic matter

red

tide?

fin fish

dilution

renewal

nutrients from land (in river)

SEA

Tett fig. 2

shell

fish

seabed

deoxygenation

pseudo-

faeces

salmon

mussels

Some of the environmental problems

resuspension

oxygen demand

phytoplankton

nutrients

sinking organic matter

red

tide?

fin fish

dilution

renewal

nutrients from land (in river)

SEA

Tett fig. 2

shell

fish

seabed

deoxygenation

pseudo-

faeces

Nutrients and phytoplankton: eutrophication:

more chlorophyll,

blooms; change in the balance of

organisms

SPRING

SUMMER

anoxic sediment

increasing organic loading

(a) the Pearson-Rosenberg paradigm for the effect of

! ! ! ! ! ! ! organic input on the benthos

increasing N & P

(b) a paradigm for the effect of nutrients on phytoplankton

Tett fig. 3

Pressures & Impacts

Nutrients and phytoplankton: eutrophication:

more chlorophyll,

blooms; change in the balance of

organisms

SPRING

SUMMER

anoxic sediment

increasing organic loading

(a) the Pearson-Rosenberg paradigm for the effect of

! ! ! ! ! ! ! organic input on the benthos

increasing N & P

(b) a paradigm for the effect of nutrients on phytoplankton

Tett fig. 3

SPRING

SUMMER

anoxic sediment

increasing organic loading

(a) the Pearson-Rosenberg paradigm for the effect of

! ! ! ! ! ! ! organic input on the benthos

increasing N & P

(b) a paradigm for the effect of nutrients on phytoplankton

Tett fig. 3

Benthic impactof organic

waste

Pressures & Impacts

Scales: spatial extent and timescale

zone Bzone C

zone B

zone A

zone A+

Tett fig 4

zone B scale - water body;

eutrophication

zone A scale - local to farm;

benthic impact! = hours

! = days

! = months

10 km

(scale of ecosystem considered must be relevant to scale of industry and impact)

farm site

regional impact

Scale of impact

impacted

reference

Scale of impact

impacted

reference

Scale of impact

impacted

reference

Ecosystem State

DPSIR• Driver - e.g. increased finfish farming

• Pressure - e.g. increased nutrient loading

• State - e.g. condition of the phytoplankton, with increases in biomass and changes in the 'balance of organisms'

• Impact - e.g. ecosystem disturbance considered `undesirable' by humans and therefore diagnostic of eutrophication

• Response - e.g. OSPAR's 'strategy to combat eutrophication'

DPSIR• Driver - e.g. increased finfish farming

• Pressure - e.g. increased nutrient loading

• State - e.g. condition of the phytoplankton, with increases in biomass and changes in the 'balance of organisms'

• Impact - e.g. ecosystem disturbance considered `undesirable' by humans and therefore diagnostic of eutrophication

• Response - e.g. OSPAR's 'strategy to combat eutrophication'

state of an ecosystem

• state = values of set of ecosystem state variables

• state = trajectories of these values in system state variable space

• state = health (or deviation from good health)

• state = WFD water quality = surface water status = chemical status and ecological status

Water Framework Directive

• applied to transitional and coastal waters (at least out to 1 n.m. from coastal baseline

• requires good chemical status and good ecological status of `surface water'

• good ecological quality requires 'good' values of the hydromorophological, physico-chemical and biological quality elements

• 'good' = only small differences from values of element under 'type-specific reference conditions'

Biological Quality elements for coastal waters

• phytoplankton: abundance and composition, biomass, frequency of blooms

• macroalgae and angiosperms: presence of disturbance-sensitive taxa; cover and abundance

• benthic invertebrates: presence of disturbance-sensitive taxa; diversity and abundance

Physico-chemical elements for coastal waters

• temperature, transparency, and concentrations of oxygen and nutrients - compared with reference condition or EQS

• specific synthetic and non-synthetic pollutants - must not exceed defined thresholds

• structure (exemplified by wood) - what is marine analogy?

• vigour (not shown) - primary production, nutrient fluxes etc

• resistance - to pressure

• resilience - in recovering from disturbance

ecosystem response to pressure

pressure

health - structural indicator

resilience pressure increasing

pressure decreasing

extent ofdisturbance

resistance

hysteresis

Components of ecosystem health

Methodology proposed for monitoring against [marine] undesirable disturbance in context of eutrophication (UWWTD) and related to WFD quality

Tett et al. (2007), Mar. Poll. Bull, 53, 282-297.

production

vigour

pressure

bulk indicator(a)

(b)

High Good Moder ate

Poor Bad

WFD quality(d)

e.g. maximum

chlorophyll

e.g. minimum

oxygen

EQS (chl)

EQS (O2)

EQS (AMBI, PCI)

EQS (prod)

pressure

structural indicator

(c) disturbance

A

B

Management for Sustainability

Management for Sustainability

• prognostic - use predictive models to guide regional and site-specific planning and discharge or resource use consent [context: EIA for sites, SEA for regions]

• diagnostic - use indicators of pressure, state and impact to interpret monitoring data, and models to guide management startegies

• on relevant scales (farm, WFD water body, regional sea)

Pressure-Impact diagram

Tett fig 8

maximum tolerable

impact

management aims to reduce pressure

below ecosystem's 'assimilative capacity'

uncertainty in knowledge of relationship

'safe' region - impact

below threshold,

allowing

for uncertainty

maximum safe pressure

(assimilative capacity)

pressure indicatore.g. waste loading per

unit area or unit

exchanged volume

functional relationship,

between pressure and

impact, obtained from

mathematical model

or local observations

impact indicatore.g. AMBI, ITI, PCI,

maximum chlorophyll,

oxygen deficiency

Pressure-Impact diagram

Tett fig 8

maximum tolerable

impact

management aims to reduce pressure

below ecosystem's 'assimilative capacity'

uncertainty in knowledge of relationship

'safe' region - impact

below threshold,

allowing

for uncertainty

maximum safe pressure

(assimilative capacity)

pressure indicatore.g. waste loading per

unit area or unit

exchanged volume

functional relationship,

between pressure and

impact, obtained from

mathematical model

or local observations

impact indicatore.g. AMBI, ITI, PCI,

maximum chlorophyll,

oxygen deficiency

assimilative capacity

Capacities

• assimilative capacity = capacity to accept, use, degrade or dilute wastes without breaching an EcoQS or EQS

-- e.g. salmon production that can be consented for a given water body without causing eutrophication

• carrying capacity = capacity to maintain a stock of resource using organisms without breaching an EcoQS

-- e.g. mussel stocking density and annual harvesting that can be supported without substantially depleting phytoplankton

(c) source for nutrient

and phytoplankton

(finfish farming)

zone B scale water body

shown as a single box

input from/

output to

zone C scale

(b) sink for nutrient

and phytoplankton

(shellfish farming)

(a) sink for nutrient,

source for

phytoplankton

(natural condition)

nutrient

phytoplankton

Peturbations of RRE ecosystems

by mariculture: Impacts become

undesirable when condition (a) is

substantially changed to (b) or (c).

(Combining (b) and (c) might

restore (a)).

Source-sink balances in coastal waters and RREs

(c) source for nutrient

and phytoplankton

(finfish farming)

zone B scale water body

shown as a single box

input from/

output to

zone C scale

(b) sink for nutrient

and phytoplankton

(shellfish farming)

(a) sink for nutrient,

source for

phytoplankton

(natural condition)

nutrient

phytoplankton

Peturbations of RRE ecosystems

by mariculture: Impacts become

undesirable when condition (a) is

substantially changed to (b) or (c).

(Combining (b) and (c) might

restore (a)).

Source-sink balances in coastal waters and RREs

!!change in WFD

phytoplankton quality element

And so ...

• ECASA has evaluated:

• indicators of pressure, state, impact and response associated with aquaculture

• models of pelagic and benthic state for scales A, B and C

• through EIA type study (and historic data) at each site and through synthesis across the sites