Sea trout in Estonia Electrofishing and habitat mapping
Klaipeda 2018
Martin Kesler 14 20 16 15 12 19 17 13 9 22 21 1110 8 1 18 6 25 23 7 5 4 3 2 24 26 2827 31 3029 32
33 1 R. Tõrvajõgi 21 Br. Valkla 42 Br. Kiruma 34 (trb. of R. Narva) 35 22 Br. Kaberla 43 R. Tirtsi 2 Br. Udria 23 R. Pirita 44 Br. Ligeoja 3 Br. Künnapõhja 36 24 R. Vääna 45 R. Pidula 37 4 R. Pühajõgi 25 R. Keila 46 Br. Oju 5 R Purtse 26 Br. Treppoja 47 Br. Vesiku 6 Br. Sõreda 48. Br. Jämaja 39 38 27 R. Vasalemma 42 41 40 7 Br. Meriküla 28 R. Kloostri 49 Br Ristioja 45 43 8 R. Pada 44 29 R. Vihterpalu 50 Br. Soonda 9 R. Kunda 50 51 30 Br. Keibu 51 R. Paadrema 46 10 R. Toolse 31 R. Veskijõgi 52 Br. Kolga 11 R. Selja 47 55 32 R. Nõva 53 R. Tõstamaa 56 12 R. Vainupea 33 R. Riguldi 54. Br. Männiku 52 53 49 13 R. Mustoja 34 R. Nuutri 55. Br. Tuuraste 54 14 Br. Altja 35 Br. Poama 56 R Reiu (trb.of R. Pärnu) 57 15 R. Võsu 58 36 Br.Õngu 57 R. Rannametsa 59 16 R. Loobu 48 60 37 R. Vanajõgi 58 R Häädemeeste 61 17 R. Valgejõgi 38 Br. Taaliku 59 Br Kadaka 62 18 R. Pudisoo 39 R. Võlupe 60 Br. Priivitsa 19 R. Loo 40 R. Leisi 61 Br Lemme 20 Br. Kuusalu 41 R. Punapea 62 Br Loode Monitoring I
Electrofishing to estimate parr density (about 50 rivers and 70-100 sites annually). Since 1974
Recently supplemented with parr otolith studies to check resident/anadromous ratio among parr.
Over 95% of parr in accessible sites have anadromous maternal parent
Rohtla et al. 2017 Monitoring II
Partial smolt trapping (mark-recapture estimate) in one river (r. Pirita)
Since 2008 Monitoring III
Spawner count since 2014 (a fence guiding fish through vaki counter, r. Pirita) Releases
No releases in 2018 Reported catches on the coast
By commercial gear 30 Main Basin 25 Size limit 50 cm Gulf of Finland
20
15 Catch(t) No information 10 about angling at 5 Sea !!! 0 THS Difference ca 15 %
Average 0+ trout parr density 2008-2017 60 Zippin 50 fishing efficiency not estimated
2 40
30
ind./100m 20
10
0 4 5 6 7 8 9 10 11 12 Total THS Difference ca 9 %
Aver. 1+ and older trout parr density 2008-2017
14 Zippin 12 fishing efficiency not estimated
10 2 8
6 ind./100m 4
2
0 4 5 6 7 8 9 10 11 12 Total THS
Habitat evaluation during inventory (mapping)
• AA quality – expected 0+ parr density 80 ind./100 m2 (20 smolts per 100 m2) • A quality – expected 0+ parr density 40 ind./100 m2 (10 smolts per 100 m2) • B quality – expected 0+ parr density 20 ind./100 m2 (5 smolts per 100 m2) • C quality – expected 0+ parr density 8 ind./100 m2 (2 smolts per 100 m2) New knowledge
• Size and location of spawning areas • Potential smolt production • Overview of migration obstacles and potential restoration/improvement sites (if necessary)
• Step II – Fish passes, new spawning sites, habitat improvement etc. THS 7 or more THS 7 THS 12 ! Local context Thank you