Sea trout in Denmark

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Tracy Nichols
7 years ago
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1 Sea trout in Denmark

2 Sea trout in Denmark 173 streams with production of trout in Baltic area (ICES SD 22 25) Majority small (< 2m wide at outlet)

4 Trout streams on Bornholm

5 - Zealand

6 Funen and Jutland

8 Overall positive development over last two decades N x W Production of wild sea trout smolt in ICES SD 22-25

9 And concomitant reductions in releases of trout N x fry 1 s parr 1yr 2 yr 1 yr smolt

10 Danish commercial catch Sea trout S.t. % of salmon Recreational fishing both as rod and line fishery sports fishing And by using fixed gear gill nets, fyke nets Catch unknown but presently under investigation

11 Ascending spawners in streams Kolding and Vejle Sportsfishery landing index Index Index Kolding Index Vejle Note effort unknown, but probably increasing during period

12 Kolding Å Avg density 0+ Avg. density 1+ and older

13 Vejle Å Avg density 0+ Avg. density 1+ and older

14 South East Jutland streams South east Jutland streams and older

15 Baggeå Bakkebæk Blykobbe Å Bobbe Å Byåen Bornholm streams Døndals Å Grødby Å Gyldenså Henrikebæk Kelse Å

17 Touristic side effects Bornholm ( Sea trout Funen ( Massive investment in releases, restoration and marketing Sea trout Zealand Recent copy of sea trout Funen under establisment Sea trout Limfjord ( Same under establishment

19 Paradox high proportion of red list streams (HELCOM Salar 2011) 45 of 173 trout streams (26%) with original population has production < 50% of capacity Most are small streams In larger streams from few sections to 47 % of tributaries Main reasons: siltation, barriers including artificial lakes - and poor habitat quality in tributaries

20 Reasons for positive development Water quality up sewage cleaning since 1970 ies Habitat quality improved since 1980 ies More lenient stream maintenance Restoration mainly after 2000 (small projects gravel addition, some barriers removed, larger projects remeandering streams)

21 Reasons for positive development Fishing restrictions in sea 100 m closed area along shore Closed areas at rivermouths Extended closed areas in many places Releases of fish gradually replaced by habitat improvements Release is only offspring from wild spawners

22 Fishing regulations at sea most important rules Minimum landing size 40 cm Closed season (only maturing fish) Closed areas at river mouths with width at outlet < 2 m 500 m from (some exceptions) Closed areas at river mouths with width at outlet > 2 m 500 m all year (expanded areas at many rivers) (some exceptions) Gillnets minimum distance to shore 100 m

23 Fishing regulations at sea most important rules Minimum distance between gears Maximum 3 gillnets per fisherman (recreational fishing only) Locally pound nets (mainly targeting herring) must have upper edge at least 10 cm below the surface Gillnet mesh sizes allowed: 1.July- 15 Nov. Mesh size < 50 mm (knot-knot) or > 65 mm (knot-knot)

24 Closed areas

25 Effect from restrictions in net fishing changed age composition

26 Sea age composition tagged trout R Kolding

27 Size composition subdiv % of recaptures < > 60 Length class (cm)

28 Rules etc. now available on mobile internet Also possible to purchase state license this way

29 Maps available on Smartphones with GPS

30 Fishing regulations in freshwater Minimum landing size 40 cm Closed season (in most rivers voluntarily extended to (29).02) 2/3 of the main stream must be kept when fishing with fixed gear Minimum distance between fixed gears in streams 100 m Mesh size (bar length) in the cod end of fyke nets must be at least 32 mm. Around dams 50 m both up and downstream are closed to fishing Only land owner or long term leaser may use fixed gear.

32 Habitat quality

33 Small but significant barriers

35 Sediment trap

39 Artificial lake before construction

40 Artificial lake established 2006

41 Artificial lake before construction

42 Artificial lake established 2003

44 VMP lake with very low smolt loss (0.1%) Vejle Å

45 8 % of stream enters artifical lake 26 ha lake, dike surrounds lake In Out Vejle Å passes lake on south side of dike

46 Restoration spawning gravel in small streams

47 Sediment traps to protect spawning grounds

48 Remaining major problems Siltation of spawning grounds also affects habitat quality Habitat quality insufficient - especially in smaller streams Shortage of gravel for spawning Remaining barriers including artificial lakes Some illegal net fishing at sea and near river mouths

STUDY PERFORMANCE REPORT

STUDY PERFORMANCE REPORT State: Michigan Study No.: 468 Project No.: F-80-R-1 Title: Natural reproduction by walleye in Saginaw Bay Period Covered: October 1, 1999 to September 30, 2000 Study Objective: