This document discusses Lake Mjøsa and Gudbrandsdalslågen river in Norway. It provides long-term data on water quality, plankton populations, and a trout species (Hunder trout) over 40 years. The data shows decreases in phosphorus levels, algal biomass, and zooplankton biomass in the lake coinciding with water quality improvements. Population data on Hunder trout consists of 7,000 individuals marked and monitored from 1966-2002. The document discusses how the SUSTAIN project can combine these extensive long-term datasets and local expertise to model and understand changes in these ecosystems over time in relation to environmental conditions and climate change.

1. Jannicke Moe 1
Freshwater Case Study:
Lake Mjøsa &
Gudbrandsdalslågen
SUSTAIN First Annual Meeting
Jannicke Moe (NIVA),
Asbjørn Vøllestad, Chloé Nater (UoO),
Atle Rustadbakken (County Gov. Hedmark)
14.01.2016

2. 14.01.2016Jannicke Moe 2
Hamar Arbeiderblad 06.01.2016
http://www.h-a.no/nyheter/mjosa-blir-varmere

3. 14.01.2016Jannicke Moe 3
Løvik m.fl. 2015
(NIVA-rapport 6848)
http://forskning.no/klima-okologi/2016/01/verdens-sjoer-blir-varmere

4. 14.01.2016Jannicke Moe 4
Year
Icecover
1970 1980 1990 2000
0
20
40
60
80
100
120
Ice cover mean changepoint: 1986
No.ofdays
Duration of ice cover
http://forskning.no/klima-okologi/2016/01/verdens-sjoer-blir-varmere
www.vassdragsforbundet.no

5. 14.01.2016Jannicke Moe 5
Mjøsa Lågen

6. The Hunder Trout
“Regular” Brown Trout Hunder Trout
• One of Europe’s largest trout
• 40 years of mark-recapture data
• Recent changes:
 Decreasing body size (shrinking)
 Altered maturity reaction norm
• Evolutionary response to dam (1966)?(Haugen et al. 2008)
• Reaction to climate change?
Chloé R. Nater

7. Hunder trout - main objectives
Stock
1) Estimation of vital rates and growth (temperature)
2) Extending to population dynamics
3) Effects of environmental conditions
4) Effects of climate change and management scenarios
Chloé R. Nater

8. Data on the Hunder trout
• 7000 individuals
• 1966-2002 (+ later)
• Mark-Recapture-Recovery
and life-history data
• Owned by Per Aass and
Atle Rustadbakken
(County Gov. of Hedmark)
• Harvesting: scattered data
(County Gov. of Oppland)
29.10.2015Jannicke Moe 8

9. 14.01.2016Jannicke Moe 9
Mjøsa Lågen

10. The "Save Mjøsa Campaign" 1977-1981
14.01.2016Jannicke Moe 10
Foto: J. E. Løvik

11. 1980 1990 2000 2010
4
6
8
10
År
TotalP(µg/L)
... has altered the water quality
14.01.2016Jannicke Moe 11
Less phosphours
1980 1990 2000 2010
1
2
3
4
5
6
År
Klf.a(µg/L)
Less algae
1980 1990 2000 2010
1000
1500
2000
2500
År
Tørrvekt(mg/m2)
Less zooplankton
Løvik & Kjellberg (2003)
Hobæk, Løvik, Rohrlack, Moe m.fl. (2012)
Løvik m.fl. (NIVA-rapport 2015)

12. 16 20 24 28 32 36 40 44
0.0
0.5
1.0
1.5
2.0
2.5
Tid på året (uke nr.)
Biomasse(mg/L)
Total biovolume
1975-1984
1985-1994
1995-2004
2005-2014
Phytoplankton:
• Lower biomass
• Later peak biomass
than in the 70s
Zooplankton:
• Lower biomass
• Earlier peak biomass
than in the 70s
• Towards mismatch?
Seasonal dynamics of plankton has
changed through the decades
14.01.2016Jannicke Moe 12
16 20 24 28 32 36 40 44
0
1000
2000
3000
Tid på året (uke nr.)
Tørrvekt(mg/m2)
ZP
1975-1984
1985-1994
1995-2004
2005-2014

13. Data on water quality and plankton:
1972-2015
29.10.2015Jannicke Moe 13

14. Data and knowledge - summary
14.01.2016Jannicke Moe 14
Excellent data
40 years
12 samples per year
All species
Great data
40 years
7,000 ind.
Few data, but
knowledge
Few data, but
knowledge

15. How can SUSTAIN best combine
and make use of...
• Extensive long-term datasets
• ... missing intermediate trophic levels
• Knowledge on Mjøsa/Lågen:
environment, species, management
• Including data owners and end-users
• Expertise on modelling and statistics
• Bayesian methods
• Participatory modelling
14.01.2016Jannicke Moe 15

16. References
Haugen, T. O. et al. 2008. Changes in selection and evolutionary responses in
migratory brown trout following the construction of a fish ladder. Evol. Appl. 1:
319–335.
Hobæk, A., J. E. Løvik, T. Rohrlack, S. J. Moe, M. Grung, H. Bennion, G. Clarke and
G. T. Piliposyan (2012). "Eutrophication, recovery and temperature in Lake
Mjøsa: detecting trends with monitoring data and sediment records."
Freshwater Biology 57(10): 1998-2014.
Løvik, J. E.; Bækken, T.; Kile, M. R.; Skjelbred, B. (2015): Tiltaksorientert
overvåking i vannområde Mjøsa. Årsrapport for 2014. NIVA-rapport 6848.
Løvik, J. E. and G. Kjellberg (2003). "Long-term changes of the crustacean
zooplankton community in Lake Mjøsa, the largest lake in Norway." Journal of
Limnology 62(2): 143-150.
14.01.2016Jannicke Moe 16