Salmon, Sea trout and Houting in the Danish Wadden Sea

Salmon, Sea-trout and Houting
Status, management and future
7 – 8 January 2015
Niels Jepsen, DTU Aqua, Silkeborg, Denmark
- & Nationalpark Vadehavet
Fishing
No gill-nets or trawling in the Wadden Sea. Only very little fyke-net
fishing mainly for eels the last 15 years.
Sportsfishing in the rivers
River species
River lamprey (Lampetra fluviatilis)
North Sea houting (Coregonus oxyrhynchus)
Sea- trout (Salmo trutta trutta)
Dace (Leuciscus leuciscus )
Salmon (Salmo salar)
Shad (Alosa fallax)
Grayling (Thymallus thymallus)
Salmon
Recreational fishing only
Trout
Houting
No fishing
Self-reproducing populations
The Danish trout populations
1000
900
800
700
600
500
400
300
200
100
0
Trout- decline
Organic pollution
Barriers - obstacles
- loss of spawning and rearing
habitat
Channelisation and dredging
Overfishing?
Anadromous fish – lifecycle is complex and can easily
be broken
Spawners
Returning
fish
Spawning reds
The sea
Eggs and fry
Juveniles (smolt)
Removal of dams and barriers
Gudenå ved Vilholt Mølle 2008
Immediately more trout, both up- and downstream
Trout density in Vejle Å
001
Number pr. m2
001
001
001
000
000
1990
1998
2003
2006
Selvreproducerende ørredbestande
Trout populations
1000
900
800
700
600
500
400
300
200
100
0
700
600
500
400
300
200
100
0
2000
1990
1980
1970
1960
1950
1940
1930
1920
1910
1900
1890
Number of salmon caught
Annual catches of Salmon in the estuary of River Skjern,
1900 - 1978
Otterstrøm (1938) and Statistic yearbooks, the Ministery of Fisheries
Stocking
Stocking – the right way
..migration barriers have been removed and habitats restored
The result of a focused, coordinated and science based management
Cormorant culling
Habitatrestauration from 1990’ies
Dynamic stocking program
Restrictions on fishing in Fjord and river
Not only in Skjern River
Angler-caught salmon 1996-1997 and 2004 - 2010
Number of salmon caught
3000
River Varde Å
2500
2000
River Kongeå
1500
River Sneum Å
1000
River Skjern Å
500
River Storå
0
2010
2009
2008
2007
2006
2005
2004
1997
1996
Salmon
The rivers now have self-containing populations of salmon, annual runs of up to
4500 salmon.
It was estimated that the value of recreational fishing in DK is 2.85 Billion/year
Salmon
Annual run in Skjern Å
Europa og North America
Runs
Grilse (1 SW)
Large salmon (MSW)
1970
1980
1990
2000
2010
Still need for a supportive stocking programme... ??
The North Sea houting
Monitored by e-fishing and gill netting – PIT tagging
LIFE project (2006 – 2012):
Budget of 13.4 million Euros
•
Two hydroelectric power plants and 11 other weirs (fish farms) have been removed,
giving 120 km of lost river habitats to the NSH
•
Channelized river sections have been re-engineered (21 km)
•
Establishment of 470 ha of new nursery area
Status 20014
•
Ribe Å: The population has been followed (PIT tagging) for many
years. Since 2011 very few individuals have been seen
•
Varde Å: Same situation as Ribe. In 2012, we could not catch one
fish in the whole system
•
Vidå: Still holds a decent population, but much smaller than in 2011.
Where’s the problem???
Foto: Torben Andersen
Foto: Lars Mejlby
Foto: Per Huniche Jensen
Foto: Axel Mortensen
Future
Salmon: Stabilization at a high level, without stocking
Trout: Improvement due to more spawning and rearing habitats (WFD)
NSH: Efficient cormorant control or extinction
Currently, in the Wadden Sea, predation from cormorants and seals
appear to be the main problem
Thanks for the attention
Tak for opmærksomheden!