Guidance  by  electricity,    joke  or  possibility?  

Uwe  Weibel,  Ins:tut  für  Umweltstudien,  Weibel  &  Ness  GmbH,  Ulrich  Rost,  EnBW  Erneuerbare  und  Konven:onelle  Erzeugung  AG  

 

Overview  

•  Blocking and guiding of downstream migrating salmon smolts/eels along an electric barrier in a bypass with optimal configuration

•  Guidance is achieved by rows of electrodes which are angled to flow

direction •  Screening of efficency by active telemetry

–  Each fish is tagged with an individually coded transmitter –  Detection in all possible migration routes by antennas in the water

•  Spring 2015: 148 Salmon smolts

•  Autumn 2016: 120 Silver eels

   

2  

Loca:on  of  the  intake  

3  

Fish barrier

Spillway

Bypass

Flow direction

Fish  barrier  

•  Three rows of electrodes with independent electric fields

•  Each electric field can be run with individual settings

•  DC current, 50 – 90 Volt •  Parameters:

–  Impulse lenght –  Distance between impulses –  Number of impulses per group –  Distance between groups of

impulses

4  

Telemetry  

•  Main principle –  Signal from transmitter (every 1,5 s) –  Detection of signal at antennas –  Stronger signal closer to the antennas,

weaker signal with increased distance –  Battery needed for active telemetry;

limited lifetime, but greater detection range

•  Abdominal implantation of individually coded transmitters (surgical operation)

•  Permit based on German Animal Protection Law granted by RP

Karlsruhe

5  

Detec:on  sites  

1.  Glasersteg,  approx.  200  meters  upstream  of  the  intake  

 3.  Slightly  upstream  fish  barrier    5.  Bypass  

7.  Hydropower  sta:on  

9.  Rotherma-­‐Brücke,  downstream  Bypass  in  the  river  

6

Detec:on  site  1  (Glasersteg)                      Detec:on  site    2  (Fish  barrier)  

Detec:on  site  4  (Hydropower  sta:on)                  Detec:on  site  5  (Rotherma)   7  

Abdominal  implanta:on  

•  At first, fish are slightly anaethetised in water with low concentration of anaethetic

•  Afterwards, narcosis by higher concentration of anaesthetic Realization 1.  Opening of abdominal cavity 2.  Insertion of transmitter in abdominal cavity 3.  Fixation of antenna on one side of abdominal cavity 4.  Suturung of the wound 5.  Desinfection

Time for surgical implantation: approx. 5 minutes/fish

•  Transmitter remains in the fish •  Use of sterile instruments •  Risk of infection very low

 8  

1.  Opening  of  abdominal  cavity   2.  Implanta:on  of  transmi_er  

3.  Fixa:on  of  antenna   4.  Suturing   9  

Trials  with  salmon  smolts  

•  Insertion point of the fish approx. 900 meters upstream fish barrier •  148 fish in 3 tranches:

–  21.04.2015: 44 fish –  27.04.2015: 56 fish –  28.04.2015: 48 fish

•  Water temperature > 10 °C •  Flow conditions upstream fish barrier 0,6 – 0,85 m/s •  Constant amount of water through spillway and bypass •  One gate at the intake was closed dureing the trial period (on the left

side next to the spillway)

10  

Results  

•  It was possible to retrace the migration route of 128 out of 148 salmon smolts

•  20 salmon smolts with only one or no detection •  Migration time mostly few hours (fastest smolt: 0,5 h from detection

site 1 to detection site 5)

•  In some cases detection only after 2-3 days (slowest salmon: 85,5 h from detection site 1 to detection site 5)

11  

12

128 Salmons

123 Salmons

111 Salmons

116 Salmons

12 Salmons

5 Salmons Weir

13

Results  Salmon  smolts  

123 Salmon smolts were detected at the fish barrier •  90 % used the spillway and could be detected at site 5

downstream

•  10 % passed the electric field

•  5 salmons used the weir for downstream migration

 

What  will  happen  while  eelmigra:on  2016?  

14  

swimming  electrodes  fixed  at  the  bo_om  

swimming  electrodes  

Bypass  construc:on  with  ver:cal  slots  and    higher  water  level  for  reduced  currents  

17  

Bypass  with  ver:cal  slots  and  Big  Packs  for  higher  water  level  

18  

Thank  you  for  your  a_en:on  and  godspeed  for  our  par:cipants  for  their  trip  to  the  Caribbean  Sea!  

Uwe  Weibel,  Ins:tut  für  Umweltstudien,  Weibel  &  Ness  GmbH,  Ulrich  Rost,  EnBW  Erneuerbare  und  Konven:onelle  Erzeugung  AG  

 

19