Download Ecological Risk Assessment

Ecological Risk Assessment – a process for prioritising research
and management in diverse and data-limited ecosystems
Shane Griffiths, Shijie Zhou, Alistair Hobday and Tony Smith
CSIRO Marine and Atmospheric Research
SPC workshop 14 June 2010
www.csiro.au
Outline
 What is an Ecological Risk Assessment?
 Existing risk assessment methods
 CSIRO ERA Methodology
 Sustainability Assessment for Fishing Effects (SAFE)
 Application in Australia’s Northern Prawn Fishery
Ecological Risk Assessment
What is an Ecological Risk Assessment?
 “An assessment that can determine the risk of a species’
population, assemblage or habitat becoming unsustainable in the
long-term due to the effect of a specific perturbation”.
 Allows scientists to provide advice to managers about “high risk”
species in order to both protect the species & ensure the longevity
and profitability of the fishery.
Ecological Risk Assessment
Australia’s Northern Prawn Fishery
 1 million km2
 115 boats
 9 prawn species
 8000-10 000 t yr-1
 AU$80 million yr-1
Ecological Risk Assessment
Australia’s Northern Prawn Fishery
 100’s of non-target species caught
 Byproduct (e.g. squid, scallops, reef fish)
 Bycatch (discarded)
 30,000 t yr-1 of bycatch discarded, mostly dead.
 Introduction of TEDs and BRDs in 2000 to reduce bycatch
Ecological Risk Assessment
Ecological Risk Assessment
Ecological Risk Assessment
 Environment Protection and Conservation Act 1999 in Australia
requires export fisheries to demonstrate ecological sustainability
 Possible for target species – but 100’s of bycatch species?
 All species equal – monitoring is expensive & impractical
 Ecosystem models – data intensive & often not species-specific
 Ecological Risk Assessment – cost-effective & data-limited
Ecological Risk Assessment
Ecological Risk Assessment Methods
 Several ecological risk assessment methods developed worldwide
 Qualitative – Likelihood-Consequence Analysis, Scale Intensity
Consequence Analysis (SICA), Fuzzy Logic Expert System
 Semi-quantitative attribute-based methods (e.g. PSA)
 Quantitative models – Sustainability Assessment for Fishing
Effects (SAFE), and stock assessment models (not often used)
Ecological Risk Assessment
CSIRO ERA Methodology
Scoping
Identify objectives
Hazard Identification
Level 1 Risk Assessment
Qualitative assessment
Medium or
High Risk
Low
Risk
Level 2 Risk Assessment
Semi-quantitative assessment
Medium or
High Risk
Level 3 Risk Assessment
Quantitative assessment
Medium or
High Risk
Ecological Risk Assessment
Low
Risk
Low
Risk
Management
response to risk
Scoping
 0 or 1 score given for a range of risk activities
 If any activity score is 1, the fishery enters Level 1 analysis
Direct impact of
Fishing
Fishing Activity
Score
(0/1)
Documentation of Rationale
Capture
Bait collection
0
No bait collection occurs
Fishing
1
Capture of organisms due to gear deployment,
retrieval and actual fishing.
Incidental behaviour
0
No specific activity identified
Bait collection
0
No bait collection occurs
Fishing
1
Organisms may come into contact with TED or net;
benthic species may be damaged by net moving over
them.
Incidental behaviour
1
Possibly hooking of sharks and hooks remaining in
the animal
Gear loss
1
Uncommon but may occur
Anchoring/ mooring
1
Occurs during day light throughout the fishery except
the JBG, where fishing usually occurs 24 hrs
Navigation/steaming
1
Continuous searching and trawling during the night,
often steaming between locations during the day.
Direct impact without
capture
Ecological Risk Assessment
Level 1 – Scale Intensity Consequence
Analysis (SICA)
 Target, bycatch, byproduct, TEP, habitat, community analyses
 If a consequence score >3 move to Level 2 - PSA
Incidental
behaviour
Ecological Risk Assessment
0
1
0
6
2 Population
size
Arius bilineatus
1.2
3
4
Confidence Score
(1-2)
Consequence
Score (1-6)
Intensity Score (16)
Operational
objective (S2.1)
Unit of analysis
Fishing Activity
Bait collection
Fishing
Sub-component
Direct
impact of
fishing
Capture
Updated
Presence (1)
Absence (0)
Spatial scale of
Hazard (1-6)
Temporal scale of
Hazard (1-6)
Component - Bycatch/Byproduct spp.
Rationale
2 Fishing occurs in 24% of the 770,000 km2 NPF managed area for
about 3 months each year => Population size likely to be affected
before major changes in other sub-components => this species of
catfish is likely to be most affected by fishing as it's been identified
as the bycatch species most at risk of depletion as it's slow-moving,
easily entangled in net mesh and has low reproductive capacity =>
intensity moderate as fishing often restricted to areas with suitable
habitat => consequence major as large impacts have been
documented and fishing likely to cause long-term decline in
population size => confidence high as impacts on bycatch well
documented
Level 2 Productivity - Susceptibility Analysis (PSA)
 Limited data required, can use “guesstimates”
 Criteria describe biological, ecological and
fishery aspects for every species
 Each species is given a rank (1-3) for each
criteria
Low 3
 Water column position
 Diel behaviour
 Locomotion etc
Susceptibility
2.5
2
1.5
High 1
1
Low
1.5
2
Recovery
2.5
3
High
 Mortality
 Fecundity
Ecological Risk Assessment
 Breeding strategy etc
Productivity - Susceptibility Analysis
Advantages
 Conceptually and mathematically simple
 Can analyse hundreds of species with limited data
 Rapid and cheap assessment using existing information
Disadvantages
 Relative ranking – are “highest risk” species really at risk?
 Thus, cannot demonstrate ecological sustainability of a fishery
Ecological Risk Assessment
Level 3 – Sustainability Assessment for Fishing
Effects (SAFE)
 New model quantifies risk on each species by estimating:
1) the proportion of the population impacted by the fishery
2) Species sustainability using a simple population model
 A simple quantitative “filtering” approach to identify any high
risk species to monitor
Ecological Risk Assessment
SAFE Data Requirements
1. Presence/absence data for each impacted species across entire
fishery managed area – fished and unfished areas
2. Susceptibility – the relative susceptibility to capture
3. Escapement - proportion of catch escaping (e.g TEDs, BRDs)
4. Post-capture survival – proportion of catch surviving discard
5. Natural mortality
Ecological Risk Assessment
Fishery Impact Component
NF
I
N F  NU
 Where I = proportion of the species population potentially impacted
 NF = Number of animals in the “fished area”
 NU = Number of animals in the “unfished area”
 But how is abundance estimated for low-value bycatch species?
Ecological Risk Assessment
A “simple” model
 Abundance calculated from presence-absence data in a model
incorporating gear-specific detection probabilities and species site
occupancy probability.

 

m


n
L( R , F , d R | m, n)    d R (1  d R ) mn R ,1    (1  d R ) m R ,1  (1  R ,1) 
 n 0  n 
  n 0

 F 1
  F 1


 

m


n
m

n
m
  d (1  d )     (1  d )   (1  )
R
R ,0
R
R,0
R ,0
  R

 

n 0  n 
n 0
 F 0
  F 0

N
N
N
A /a

 
 
a  
a  
a 
 mi  ni
 0 


mi  ni
mi
L( N , D | mi , ni , A, a)     D (1  D)
1  1       (1  D) 1  1     1   
A   
A   
A 
i 1  ni 
 
 
 ini 10 


ni  0 
A1 / a
Huh…???
Ecological Risk Assessment
Fishery Impact Component
F  Iq( 1   )S
 Where F = adjusted proportion of the species population impacted
 I = proportion of the species population potentially impacted
 q = the relative susceptibility of a species by a particular gear type
 Experimental data (Great Barrier Reef)
 E = proportion escaping after entering the net (e.g. TED & BRD)
 S = proportion of the landed catch surviving discarding
 Species-specific data not available for some parameters. Used data from
closely related species or “ecomorphotypes”
Ecological Risk Assessment
Hypothetical Example
NPF “Fishery” >5 boat days
White tip shark distribution
 The fishery potentially impacts 115700 of 479800 fish = 24%
 A “catchability” of 0.3 for a trawl reduces impact to 7.2%
 TED “escapement” of 50% reduces impact to 3.6%
 Post-capture survival of 65% results in final impact of 2.3%
Ecological Risk Assessment
Population model
 Once fishing mortality calculated, the sustainability of the population is
estimated using a modified Graham-Schaefer’s production model
 Natural mortality used to calculate the maximum sustainable fishing
mortality (FMSM) before the population begins to decline
 If fishing mortality exceeds the (FMSM) reference point, the population
is at “high risk” of becoming unsustainable
 Management action would then be to remove the risk or monitor the
species and apply more rigorous populations models to assess status
Ecological Risk Assessment
NPF Teleost Bycatch Results
1.00
Fishing mortality + 95%CI
0.80
Dendrochirus brachypterus
0.60
Scorpaenopsis venosa
0.40
0.20
0.00
0.00
0.20
0.40
0.60
Maximum sustainable fishing mortality rate
Ecological Risk Assessment
0.80
1.00
Conclusions
 Ecological Risk Assessment can be a rapid and cost-effective way of
assessing the risk of anthropogenic activities on marine organisms
 CSIRO ERA methodology is a simple method that engages all
stakeholders to assess risks
 The process is transparent and may increase acceptance of risks and
uptake of management measures by stakeholders
 New quantitative risk assessment methods (SAFE) can allow fishery
managers to more confidently introduce risk mitigation measures
 Reduces cost to the fishery to only monitor/manage true “at risk”
species
Ecological Risk Assessment
Thank You
Contact: Shane Griffiths
Phone: 07 3826 7364
Email:
Web:
[email protected]
www.csiro.au
www.csiro.au