1. Evaluation of potential trophic impacts from hake
(M. merluccius) emergence in the North Sea.
3rd International Symposium
Effects of Climate Changes on World’s Ocean
Xochitl Cormon1, A. Kempf2, K. Rabhi1, M. Rouquette1,
Y. Vermard3, M. Vinther4 and P. Marchal1
1IFREMER, Channel and North Sea Fisheries Research Unit, Boulogne-sur-Mer
2Thünen Institute, Institute of Sea Fisheries, Hamburg
3IFREMER, Unit of Fisheries Ecology and Modelling, Nantes
4Denmark Technical University, DTU Aqua, Charlottenlund
21-27 March 2015, Santos, Brazil
3. Introduction Species presentation
Saithe and hake in the North Sea
2000 2002 2004 2006 2008 2010 2012
−2−1012
2000 2002 2004 2006 2008 2010 2012
−2−1012
2000 2002 2004 2006 2008 2010 2012
−2−1012
Saithe
Hake Q1
Hake Q3
Standardized spawning stock biomass trends (ICES, 2013; Baudron and Fernandes, 2014)
XOCHITL.CORMON@IFREMER.FR Hake emergence trophic impacts PICES 2015, 27 March 1 / 8
4. Introduction Species presentation
Saithe and hake in the North Sea
?
COMPETITION
?
2000 2002 2004 2006 2008 2010 2012
−2−1012
2000 2002 2004 2006 2008 2010 2012
−2−1012
2000 2002 2004 2006 2008 2010 2012
−2−1012
Saithe
Hake Q1
Hake Q3
Standardized spawning stock biomass trends (ICES, 2013; Baudron and Fernandes, 2014)
XOCHITL.CORMON@IFREMER.FR Hake emergence trophic impacts PICES 2015, 27 March 1 / 8
5. Introduction State of the knowledge
Step by step towards competition theory (Link and Auster,
2013)
1. Opposite trends
2000 2002 2004 2006 2008 2010 2012
−2−1012
2000 2002 2004 2006 2008 2010 2012
−2−1012
2000 2002 2004 2006 2008 2010 2012
−2−1012
Saithe
Hake Q1
Hake Q3
Since early 2000’s in the North
Sea:
Opposite trends of
population abundance.
XOCHITL.CORMON@IFREMER.FR Hake emergence trophic impacts PICES 2015, 27 March 2 / 8
6. Introduction State of the knowledge
Step by step towards competition theory (Link and Auster,
2013)
2. Spatial overlap,
Cormon et al., 2014
0 5 10
5254565860
0.0
0.2
0.4
0.6
0.8
1.0
0 5 10
5254565860
−0.4
−0.2
0.0
0.2
0.4
0 5 10
5254565860
0.0
0.2
0.4
0.6
0.8
1.0
0 5 10
5254565860
−0.4
−0.2
0.0
0.2
0.4
Winter and Summer, (2007-2012) - (1991-1996)
Since early 2000’s in the North
Sea:
Opposite trends of
population abundance.
Increase of hake probability
of presence and of
saithe-hake overlap.
XOCHITL.CORMON@IFREMER.FR Hake emergence trophic impacts PICES 2015, 27 March 2 / 8
7. Introduction State of the knowledge
Step by step towards competition theory (Link and Auster,
2013)
3. Drivers of probable habitats,
Cormon et al., 2014
Hake Overlap
Winter Summer Winter Summer
NS
NS
Since early 2000’s in the North
Sea:
Opposite trends of
population abundance.
Increase of hake probability
of presence and of
saithe-hake overlap.
Importance of temperature
and Norway pout presence
for probable habitats.
XOCHITL.CORMON@IFREMER.FR Hake emergence trophic impacts PICES 2015, 27 March 2 / 8
8. Introduction State of the knowledge
Step by step towards competition theory (Link and Auster,
2013)
4. Occurences of prey in winter
0.00
0.25
0.50
0.75
1.00
H S
Species
Percentagemobserved
Legend
Norwaympout
Gadiforms
Clupeiforms
Othermfish
Other
Prelim
inary
results
Study in progress
Since early 2000’s in the North
Sea:
Opposite trends of
population abundance.
Increase of hake probability
of presence and of
saithe-hake overlap.
Importance of temperature
and Norway pout presence
for probable habitats.
Potential diet overlap.
XOCHITL.CORMON@IFREMER.FR Hake emergence trophic impacts PICES 2015, 27 March 2 / 8
9. Introduction State of the knowledge
Step by step towards competition theory (Link and Auster,
2013)
5. Limiting resources?
Last but not least condition to
assume competition
Since early 2000’s in the North
Sea:
Opposite trends of
population abundance.
Increase of hake probability
of presence and of
saithe-hake overlap.
Importance of temperature
and Norway pout presence
for probable habitats.
Potential diet overlap.
XOCHITL.CORMON@IFREMER.FR Hake emergence trophic impacts PICES 2015, 27 March 2 / 8
14. Introduction Objectives
Limiting resources?
Saithe-Hake-Norway pout
threesome
Pros
Main shared prey
NS distribution
overlapping
Bottom-up
processes only
Assessed species
XOCHITL.CORMON@IFREMER.FR Hake emergence trophic impacts PICES 2015, 27 March 3 / 8
15. Introduction Objectives
Limiting resources?
Saithe-Hake-Norway pout
threesome
Pros
Main shared prey
NS distribution
overlapping
Bottom-up
processes only
Assessed species
Cons
Simplistic
XOCHITL.CORMON@IFREMER.FR Hake emergence trophic impacts PICES 2015, 27 March 3 / 8
16. Introduction Objectives
Limiting resources?
Saithe-Hake-Norway pout
threesome
Pros
Main shared prey
NS distribution
overlapping
Bottom-up
processes only
Assessed species
Cons
Simplistic
Research question
What are the potential impacts of hake on saithe trough Norway pout
availability in the North Sea?
XOCHITL.CORMON@IFREMER.FR Hake emergence trophic impacts PICES 2015, 27 March 3 / 8
17. Materials and methods SMS
Materials and methods
SMS, Lewy and Vinther, (2004)
XOCHITL.CORMON@IFREMER.FR Hake emergence trophic impacts PICES 2015, 27 March 4 / 8
18. Materials and methods SMS
Materials and methods
SMS, Lewy and Vinther, (2004)
Hake?
XOCHITL.CORMON@IFREMER.FR Hake emergence trophic impacts PICES 2015, 27 March 4 / 8
19. Materials and methods SMS
Materials and methods
SMS, Lewy and Vinther, (2004)
Hake?
WGSAM 2014 key-run
XOCHITL.CORMON@IFREMER.FR Hake emergence trophic impacts PICES 2015, 27 March 4 / 8
20. Materials and methods SMS
Materials and methods
SMS, Lewy and Vinther, (2004)
Hake?
WGSAM 2014 key-run
Bottom-up?
XOCHITL.CORMON@IFREMER.FR Hake emergence trophic impacts PICES 2015, 27 March 4 / 8
21. Materials and methods SMS
Materials and methods
SMS, Lewy and Vinther, (2004)
Hake?
WGSAM 2014 key-run
Bottom-up?
Cormon et al., in prep
XOCHITL.CORMON@IFREMER.FR Hake emergence trophic impacts PICES 2015, 27 March 4 / 8
22. Materials and methods Parametrization and scenarios
Parametrization and scenarios
Parametrization
XOCHITL.CORMON@IFREMER.FR Hake emergence trophic impacts PICES 2015, 27 March 5 / 8
23. Materials and methods Parametrization and scenarios
Parametrization and scenarios
Parametrization
Stock-recruitment: Ricker (saithe & Norway pout), deterministic.
XOCHITL.CORMON@IFREMER.FR Hake emergence trophic impacts PICES 2015, 27 March 5 / 8
24. Materials and methods Parametrization and scenarios
Parametrization and scenarios
Parametrization
Stock-recruitment: Ricker (saithe & Norway pout), deterministic.
Saithe growth: VBGF and linear relationship between K and Norway
pout average on two years
XOCHITL.CORMON@IFREMER.FR Hake emergence trophic impacts PICES 2015, 27 March 5 / 8
25. Materials and methods Parametrization and scenarios
Parametrization and scenarios
Parametrization
Stock-recruitment: Ricker (saithe & Norway pout), deterministic.
Saithe growth: VBGF and linear relationship between K and Norway
pout average on two years
Consumption rates: Allometric relationship with mean weight.
XOCHITL.CORMON@IFREMER.FR Hake emergence trophic impacts PICES 2015, 27 March 5 / 8
26. Materials and methods Parametrization and scenarios
Parametrization and scenarios
Parametrization
Stock-recruitment: Ricker (saithe & Norway pout), deterministic.
Saithe growth: VBGF and linear relationship between K and Norway
pout average on two years
Consumption rates: Allometric relationship with mean weight.
Fishery mortality: Status-quo from hindcast.
XOCHITL.CORMON@IFREMER.FR Hake emergence trophic impacts PICES 2015, 27 March 5 / 8
27. Materials and methods Parametrization and scenarios
Parametrization and scenarios
Parametrization
Stock-recruitment: Ricker (saithe & Norway pout), deterministic.
Saithe growth: VBGF and linear relationship between K and Norway
pout average on two years
Consumption rates: Allometric relationship with mean weight.
Fishery mortality: Status-quo from hindcast.
Hindcast & Forecast: 1974-2013 & 2014-2065.
XOCHITL.CORMON@IFREMER.FR Hake emergence trophic impacts PICES 2015, 27 March 5 / 8
28. Materials and methods Parametrization and scenarios
Parametrization and scenarios
Parametrization
Stock-recruitment: Ricker (saithe & Norway pout), deterministic.
Saithe growth: VBGF and linear relationship between K and Norway
pout average on two years
Consumption rates: Allometric relationship with mean weight.
Fishery mortality: Status-quo from hindcast.
Hindcast & Forecast: 1974-2013 & 2014-2065.
Scenarios
Status-quo Growth Extreme Moderate
Growth X O O O
Hake change 1 1 1.10 1.05
Period 2011-2013 2011-2013 2014-2025 2014-2025
XOCHITL.CORMON@IFREMER.FR Hake emergence trophic impacts PICES 2015, 27 March 5 / 8
29. Results and discussion Results
Status-quo results
Hake in number of individuals
qqqqqqqqqqqqqqqqqqq
q
q
qq
q
q
qqqq
qq
q
qqq
q
q
q
q
q
qqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqq
20
40
60
80
1975 2000 2025 2050
Years
AbundanceatQ1(1E3)
Scenarios q status−quo
XOCHITL.CORMON@IFREMER.FR Hake emergence trophic impacts PICES 2015, 27 March 6 / 8
38. Results and discussion Conclusion and prospects
What do we know and what’s next?
Conclusions
Lower saithe biomass estimates with growth.
XOCHITL.CORMON@IFREMER.FR Hake emergence trophic impacts PICES 2015, 27 March 8 / 8
39. Results and discussion Conclusion and prospects
What do we know and what’s next?
Conclusions
Lower saithe biomass estimates with growth.
Dominance of saithe and hake in predation on Norway pout.
XOCHITL.CORMON@IFREMER.FR Hake emergence trophic impacts PICES 2015, 27 March 8 / 8
40. Results and discussion Conclusion and prospects
What do we know and what’s next?
Conclusions
Lower saithe biomass estimates with growth.
Dominance of saithe and hake in predation on Norway pout.
Impact of hake on Norway pout and on saithe biomass.
XOCHITL.CORMON@IFREMER.FR Hake emergence trophic impacts PICES 2015, 27 March 8 / 8
41. Results and discussion Conclusion and prospects
What do we know and what’s next?
Conclusions
Lower saithe biomass estimates with growth.
Dominance of saithe and hake in predation on Norway pout.
Impact of hake on Norway pout and on saithe biomass.
Limits
Simplistic.
XOCHITL.CORMON@IFREMER.FR Hake emergence trophic impacts PICES 2015, 27 March 8 / 8
42. Results and discussion Conclusion and prospects
What do we know and what’s next?
Conclusions
Lower saithe biomass estimates with growth.
Dominance of saithe and hake in predation on Norway pout.
Impact of hake on Norway pout and on saithe biomass.
Limits
Simplistic.
Uncertainties.
XOCHITL.CORMON@IFREMER.FR Hake emergence trophic impacts PICES 2015, 27 March 8 / 8
43. Results and discussion Conclusion and prospects
What do we know and what’s next?
Conclusions
Lower saithe biomass estimates with growth.
Dominance of saithe and hake in predation on Norway pout.
Impact of hake on Norway pout and on saithe biomass.
Limits
Simplistic.
Uncertainties.
Prospects
Stochastic recruitment.
XOCHITL.CORMON@IFREMER.FR Hake emergence trophic impacts PICES 2015, 27 March 8 / 8
44. Results and discussion Conclusion and prospects
What do we know and what’s next?
Conclusions
Lower saithe biomass estimates with growth.
Dominance of saithe and hake in predation on Norway pout.
Impact of hake on Norway pout and on saithe biomass.
Limits
Simplistic.
Uncertainties.
Prospects
Stochastic recruitment.
Fishery scenarios.
XOCHITL.CORMON@IFREMER.FR Hake emergence trophic impacts PICES 2015, 27 March 8 / 8
45. The End
The End...
(: Travel support :)
Baudron, A. and Fernandes, P. (2014). "Adverse consequences of stock recovery: European hake, a new “choke” species under
a discard ban?" Fish and fisheries. doi: 10.1111/faf.12079.
Cormon, X., Loots, C., Vaz, S., Vermard, Y. and Marchal, P. (2014). "Spatial interactions between saithe (Pollachius virens)
and hake (Merluccius merluccius) in the North Sea." ICES Journal of Marine Science. doi: 10.1093/icesjms/fsu120.
Cormon, X., Ernande B., Kempf, A., Vermard, Y., and Marchal, P. (in prep). "Bottom-up processes in the North Sea, an
investigation of North Sea saithe growth characteristics in relation to environmental factors."
ICES (2013). "Saithe in Subareas IV, VI and Division IIIa." Report of the Working Group on the Assessment of Demersal Stocks
in the North Sea and Skagerrak (WGNSSK) CM/ACOM:13:565-609.
Lewy P. and Vinther M. (2004) "SMS, A stochastic age-length-structured multispecies model applied to North Sea and Baltic
Sea stocks."
Link J. and Auster P. (2013) "The challenges of evaluating competition among marine fishes: who cares, when does it matter,
and what can we do about it?" Bulletin of Marine Science: 89(1):213-247.
XOCHITL.CORMON@IFREMER.FR Hake emergence trophic impacts PICES 2015, 27 March 8 / 8
