Download Setting target reference points for secondary species in the SESSF

Setting target
reference points
for secondary
species in the
SESSF
Simon Vieira, Mary Hormis, Andrew Penney & James Woodhams
January 2013
Research by the Australian Bureau
of Agricultural and Resource Economics and Sciences
Background
• There is general acceptance that applying individual MEY
targets to all stocks in the SESSF is not consistent with fisherywide MEY .
• In 2012 RAGs identified secondary species and provided catch
recommendations for these species under both MSY and MEY.
• This was done without any formal criteria or research based
justification.
• AFMA requested ABARES to fill this gap in December 2012.
Department of Agriculture,
Fisheries and Forestry
Setting target reference points for secondary species in the SESSF
Simon Vieira
31 January 2013
2
Objectives
• Define the key issues related to targeting MEY across a multispecies fishery .
• Outline the key questions for management.
• Provide formal principles and criteria for identifying non-target
species.
• Outline the key factors that will influence target reference
points for secondary species.
• Discuss the implications of pursuing lower target reference
points such as BMSY for secondary species.
Department of Agriculture,
Fisheries and Forestry
Setting target reference points for secondary species in the SESSF
Simon Vieira
31 January 2013
3
What does the Harvest Strategy Policy say?
Fishery wide MEY
MEY applies to the fishery as a whole and is optimised across all species in the fishery.
Trade offs
Given the different biology and economic characteristics of different species, there are likely
to be trade-offs between the profits of different species.
To maximise the overall profits of a fishery, it may be necessary to forego some profits of
one species in order to generate higher profits from another.
Limits
Some secondary species (e.g. lower value species) may be fished at levels that will result in
their biomass remaining below their target biomass reference point (BMEY). The biomass of
these secondary species must be maintained above BLIM.
By optimising MEY across the fishery, some individual stocks may be below B MSY. The
estimated biomass of all species must be maintained above their limit reference point, BLIM.
Considerations
- Demonstrating that economic modelling and other advice clearly supports such action
- No cost-effective, alternative management options are available.
- The associated ecosystem risks have been considered in full.
Department of Agriculture,
Fisheries and Forestry
Setting target reference points for secondary species in the SESSF
Simon Vieira
31 January 2013
4
Theoretical justification: MEY
BMEY
MEY
revenue
Fishing Effort
Revenue
Yield (Catch) / $
$
BMSY
MSY
MSY
Theoretical justification: two stock MEY
Yield / $
Stock 1
Revenue
Stock 2
Revenue
Fishing Effort
S1
BMEY
S2
BMEY
Theoretical justification: key points
• The individual MEY effort level for the more profitable Stock 1 is
higher than that for Stock 2.
• Operating at Stock 1’s individual MEY biomass (BMEY) will require
that Stock 2’s biomass be below its individual BMEY (and BMSY
here).
• Stock 2’s TAC will constrain the catch of Stock 1’s TAC:
- some significant level of profit will be foregone.
Department of Agriculture,
Fisheries and Forestry
Setting target reference points for secondary species in the SESSF
Simon Vieira
31 January 2013
7
Theoretical justification: key points
• Discarding of Stock 2 means that can operate at Stock 1’s BMEY
but this will result in a fish down of Stock 2.
• Fishery-wide MEY will be a compromise between the two (refer
to paper).
Department of Agriculture,
Fisheries and Forestry
Setting target reference points for secondary species in the SESSF
Simon Vieira
31 January 2013
8
Key questions for management
Given the complexity of actually doing multi-species
bioeconomic modelling, a second best solution is preferred.
To improve the situation, we need to address two questions:
• What species can be defined as a secondary species?
• What is an appropriate MEY-based target reference point for
a secondary species?
Department of Agriculture,
Fisheries and Forestry
Setting target reference points for secondary species in the SESSF
Simon Vieira
31 January 2013
9
Identifying secondary stocks
Secondary stock defined as:
• A non-targeted stock whose catch exhibits a relatively low
economic return relative to the return of targeted species it
is caught with;
• Will typically make up a relatively low proportion of GVP
and will not be a driver of fishery profit.
Classification should be based on relative contribution to GVP
and the degree to which it is targeted:
• Consistent with CSIRO and RAG classification approach;
• However, no threshold based criteria were used.
Department of Agriculture,
Fisheries and Forestry
Setting target reference points for secondary species in the SESSF
Simon Vieira
31 January 2013
10
Commonwealth Trawl Sector secondary
stocks
Quota species
Smooth Oreo
Ribaldo
Ocean perch
John dory
Jackass morwong
Redfish
Oreo, Basket
Silver trevally
Mirror dory
Pink ling
Department of Agriculture,
Fisheries and Forestry
Price ($/kg)
$4.25
$2.16
$3.21
$6.70
$2.58
$3.47
$3.28
$3.89
$2.22
$5.49
Sum of
Value
($'000)
Percentage
of CTS
scalefish
value
Percentage
of catch
targeted
0%
0%
1%
1%
2%
1%
1%
1%
2%
8%
1%
14%
16%
26%
27%
36%
41%
45%
46%
48%
$7
$112
$657
$597
$1,041
$298
$350
$701
$1,217
$4,126
Setting target reference points for secondary species in the SESSF
Simon Vieira
31 January 2013
11
Commonwealth Trawl Sector secondary
stocks
Department of Agriculture,
Fisheries and Forestry
Setting target reference points for secondary species in the SESSF
Simon Vieira
31 January 2013
12
Gillnet, Hook & Trap Sector secondary
stocks
Quota species
Price ($/kg) Sum of
Value
($'000)
Percentage Percentage
of GHTS
of catch
shark value targeted
Gummy shark
$6.37
$12,233
89%
98%
School shark
$4.65
$988
7%
41%
Sawshark
$2.20
$254
2%
1%
Elephantfish
$0.97
$75
1%
1%
Department of Agriculture,
Fisheries and Forestry
Setting target reference points for secondary species in the SESSF
Simon Vieira
31 January 2013
13
Identifying secondary stocks: additional
considerations
Sustainability
• Unconstrained fishery-wide MEY may put the sustainability of
a secondary stock at risk, depending on its biological
characteristics.
• It remains a requirement under the HSP to maintain all stocks
within acceptable and sustainable biomass ranges, and
particularly above BLIM reference points.
• None of the identified secondary species are classified as
overfished or subject to overfishing, but some are uncertain.
Department of Agriculture,
Fisheries and Forestry
Setting target reference points for secondary species in the SESSF
Simon Vieira
31 January 2013
14
Identifying secondary stocks: additional
considerations
Quota latency
In the example, the secondary species TAC would likely be filled before all
the TAC of the primary stock is taken.
A high amount of latent quota for a stock suggests that the benefits of
managing that stock as secondary are likely to be low.
Can result in there being low economic returns to fully catching the
secondary species TACs, influenced by:
• Transaction costs of acquiring quota;
• The profitability of the secondary and primary stock;
• The additional primary stock catch expected with catching a unit of
secondary stock.
Department of Agriculture,
Fisheries and Forestry
Setting target reference points for secondary species in the SESSF
Simon Vieira
31 January 2013
15
MSY targets for secondary species: risks
and benefits
Applying BMSY targets instead of BMEY will result in:
• Higher TACs for secondary stocks.
• Lower biomass of secondary stocks;
There are three main sources of potential benefit:
• Increased secondary species revenue;
• Increased target species revenue;
• Decreased costs for a given total multi-species
catch.
Department of Agriculture,
Fisheries and Forestry
Setting target reference points for secondary species in the SESSF
Simon Vieira
31 January 2013
16
Increased secondary species revenue
Secondary Species MSY rec. MEY rec. Difference 2011-12
catch
catch
in catch financial
(tonnes) (tonnes) (tonnes) year ($/kg,
prelim.)
Redfish * (T3)
Difference
in GVP
terms
($,000)
TAC
(2011-12
season,
tonnes)
Quota
latency
(2011-12
season)
3,843
2,932
911
$3.47
$3,161
276
66%
John Dory ** (T3)
762
614
148
$6.70
$992
221
60%
Ribaldo (T4)
321
232
89
$2.16
$192
168
32%
Ocean Perch (T4)
457
330
(Inshore, Offshore) (174, 283) (126, 204)
127
$3.21
$408
300
24%
Saw shark*** (T4)
324
234
90
$2.20
$198
226
18%
Elephantfish ****
(T4)
258
186
72
$0.97
$70
89
15%
Department of Agriculture,
Fisheries and Forestry
Setting target reference points for secondary species in the SESSF
Simon Vieira
31 January 2013
17
Increased target species revenue
Secondary species
Secondary
species
quota
latency
(2011-12
season)
Major companion
species as
identified in Klaer
(2011)
Companion
target species
quota latency
(2011-12 season)
Percentage of
secondary species
catch taken with
major companion
(Klaer 2011)
Redfish (trawl)
John dory (trawl)
Ribaldo (trawl)
66%
60%
32%
Ocean perch (trawl)
24%
Silver trevally (trawl)
69%
0%
0%
66%
13%
0%
98%
0%
28%
13%
0%
39%
31%
46%
21%
20%
12%
12%
29%
20%
15%
23%
10%
Sawshark (Gillnet)
Elephantfish (Gillnet)
18%
15%
Flathead
Flathead
Deepwater shark
Blue grenadier
Pink ling
Other oreos
Pink ling
Mirror dory
Blue Grenadier
Flathead
Deepwater
flathead
Gummy shark
Gummy shark
18%
18%
96%
98%
Department of Agriculture,
Fisheries and Forestry
Setting target reference points for secondary species in the SESSF
Simon Vieira
31 January 2013
18
Decreased costs for a given catch
• Unconstrained, fishers are most likely to direct their effort
towards areas where they expect to achieve the most
profitable catch.
• In a multi-species fishery, the decision on where to operate
will be different if a fisher is constrained by their limited
holding and access to quota for a given secondary species.
• The fisher’s objective will then be to operate in an area where
it is expected that the target species can be caught most
profitably with the least likelihood of catching the constraining
secondary species.
Department of Agriculture,
Fisheries and Forestry
Setting target reference points for secondary species in the SESSF
Simon Vieira
31 January 2013
19
Minimum Safe Levels for secondary species
Must maintain stocks above BLIM but how close can we go?
‘Precautionary approach’ limit reference points:
• Proposed by ICES (1997) and taken up in the FAO Stock
Assessment Manual (Cadima 2003);
• Deals with stock assessment uncertainty and the
requirement for a precautionary approach to ensure
biological productivity not jeopardised.
Recommended Bpa would be 29% - 33% B0, about half way
between the current default proxies for BMSY and BLIM.
Department of Agriculture,
Fisheries and Forestry
Setting target reference points for secondary species in the SESSF
Simon Vieira
31 January 2013
20
Conclusions
• The potential increase in returns are low from secondary
species revenue increases.
• Difficult to quantify returns from increased catches of target
species, but likely to be the major source of benefit.
• Difficult to quantify returns from a reduction in unit costs of
fishing due to changed behaviour. Option to discard
dampens the relevant incentives.
• How low can you go? – an important question that will need
to be addressed eventually.
• The proposed suite of alternative targets should be MSE
tested to ensure risk of B < BLIM is <10% for all species.
Department of Agriculture,
Fisheries and Forestry
Setting target reference points for secondary species in the SESSF
Simon Vieira
31 January 2013
21