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Table 5 Stunning and killing of rainbow trout in the field study: overview of applied stunning methods, electrical parameters, stunning success and times

From: Is humane slaughtering of rainbow trout achieved in conventional production chains in Germany? Results of a pilot field and laboratory study

Stunning intervention.

Electrical parameters

 

Stunning success

Injuries/ mis-hits

Time until exsanguination

Behavioural signs at time of slaughtering

Water conductivity [μS/cm; MIN-MAX]

Voltage [V; MIN-MAX]

Electric current densities [A/dm2; MIN-MAX]

Stunning time (seconds or minutes)

[%; (n/total number of fish)]

[%; (n/total number of fish)]

[seconds or minutes; MIN-MAX]

[%; (n/total number of fish)]

Stunning by percussion (n = 8 stunning interventions)

1

n.a.

n.a.

n.a.

n.a.

83.0 (7/11)

0.0 (0/11)

60–95 s.

27.0 (3/11)

2

n.a

n.a

n.a

n.a

95.0 (19/20)

50.0 (4/8)

15–20 s.

0.0 (0/20)

3

n.a

n.a

n.a

n.a

95.0 (19/20)

70.0 (7/10)

15–30 min.

5.0 (1/20)

4

n.a.

n.a

n.a

n.a.

100.0 (20/20)

10.0 (1/10)

5–10 min.

0.0 (0/20)

5

n.a.

n.a.

n.a.

n.a.

100.0 (20/20)

10.0 (1/10)

20 s. – 5 min.

0.0 (0/20)

6

n.a.

n.a.

n.a.

n.a.

80.0 (16/20)

50.0 (5/10)

10–20 min.

10.0 (2/20)

7

n.a.

n.a.

n.a.

n.a.

100.0 (10/10)

100.0 (10/10)

2–5 min.

0.0 (0/10)

8

n.a.

n.a.

n.a.

n.a.

95.0 (19/20)

50.0 (5/10)

20–25 min.

10.0 (1/10)

Summary Percussion (N = 8)

n.a

n.a

n.a

n.a

92.2 (130/141)

41.8 (33/79)

15 s. – 30 min.

5.3 (7/131)

Electrical stunning (a: in a water bath,n = 9 stunning interventions;b: on wet electrodes outside the water, n = 1 stunning intervention)

9a

453

36–47

0.0163–0.0213

3 min.

100.0 (10/10)

10.0 (1/10)

2–5 min.

0.0 (0/10)

10a

334

33–36

0.0245–0.0267

1 min.

70.0 (14/20)

60.0 (6/10)

60–90 s.

35.0 (7/20)

11a

613

36

0.0061

30–45 s.

100.0 (10/10)

0.0 (0/10)

10–120 min.

0.0 (0/10)

12a

604

36

0.0064

30–45 s.

100.0 (10/10)

0.0 (0/10)

10–120 min.

0.0 (0/10)

13a

438

34

0.0196

60 s.

100.0 (20/20)

20.0 (2/10)

20–90 min

10.0 (1/10)

14a

969

20

0.121

20 s.

20.0 (2/10)

30.0 (3/10)

2–4 min.

80.0 (8/10)

15a

910

20

0.114

20 s.

20.0 (2/10)

30.0 (3/10)

2–4 min.

70.0 (7/10)

16a

756

230

0.435

30 s.

95.0 (19/20)

20.0 (2/10)

2 min.

10.0 (1/10)

17a

756

230

0.435

30 s.

95.0 (19/20)

40.0 (4/10)

2 min.

10.0 (1/10)

19b

209

53.3

Not measurable

2 min.

95.0 (19/20)

70.0 (7/10)

2–5 min.

10.0 (1/10)

Summary Electrical stunning (N = 10)

334–969

20–230

0.0061–0.435

20 s. – 3 min.

83.3 (125/150)

28.0 (28/100)

1–120 min.

23.6 (26/110)

Electrical stunning followed by percussion (c: electrical stunning in a water bath, n = 2;d: electrical stunning first on wet electrodes outside the water followed by electrical stunning in a water bath, n = 1)

20c

577

37.6

0.0434

20 s.

100.0 (10/10)

20.0 (2/10)

20 s.

0.0 (0/10)

21c

822

28.5

0.146

1 min.

100.0 (6/6)

0.0 (0/6)

60–90 s.

0.0 (0/6)

22d

441

36

0.1359

8 min

(3 min dry,

5 min in water)

100.0 (20/20)

0.0 (0/10)

2–5 min.

0.0 (0/10)

Summary Electrical stunning followed by percussion

(N = 3)

577–822

28.5–37.6

0.0434–0.146

20 s. – 8 min.

100.0 (26/26)

12.5 (2/16)

20 s. – 5 min.

0 (0/16)