... of mussels for SMEs in the European mussel industry. This power point and videos were presented by Sara Barrento during the Association of Scottish Shellfish Growers 2012 in Oban. In 2011 several mussel farmers were interviewed in Scotland, Ireland and Norway. This presentation addresses two questions raised by the mussel farmers: 1) Can oxygen be maintained above 5 mg/L at flows lower than 6500 L/h? 2)Transport with ice: What is the temperature inside mussels? There are two videos the first video is on slide 34 and the caption is as follows Mussels can survive for extended periods out of water and can be traded for human consumption as live animals. Usually mussels are transported live without water. However, when exposed to air, mussels gape in an attempt to maintain oxygen levels. Gaping occurs when mussels are out of water and is basically the opening of the valves. In this video it can be seen that mussels gape intermittently, and the smaller mussels gape more often, loosing more water than bigger mussels. The footage was taken during a 48 h period, the dark images correspond to the night period. Mussels were kept out of the water in a temperature controlled room set to 18 degrees Celsius. The temperature was chosen because everything happens faster at higher temperatures. The same type of response was shown at 5 degrees, but instead of capturing images during 48 h, the time is then extended to one week, which further demonstrates the importance of keeping low temperatures. The second video is on slide 35 and the caption is as follows: this video shows mussels in an aquarium that were given green microalgae. Mussels start filtrating immediately and at the same time it can be seen that mussels release pseudofaeces. Quite often the mussel foot comes out from the valves and extends. This video is ideal to show how fast mussels filtrate and the importance of filtration during depuration. Many physiological events can be explained and introduced with these images. These videos were supported by The European Commission through the Collaborative Research Project ''MusselsAlive : Development of best Practice and new technology for grading, handling, transportation, conditioning and storage of mussels for SMEs in the European mussel industry".

2. ASSG 2011

4. Development
of best practice
and new technology for ...

5. Keep quality & Reduce waste
Harvest
Consumer

6. Keep quality & Reduce waste
SMEs in the
European mussel industry
Research

10. Practices... Companies... Countries...
different harvesting
different CLIENTS different REGULATIONS
TECHNIQUES
different TRANSPORT different COMMERCIAL different TRADE CHAINS
conditions CHANNELS

11. Conditions of approval Scotland
Specifications The system is approved for the purification of
{species (latin name)} .The system shall consist of a tank measuring 1160 x 980 x
600mm internally containing a minimum water volume of X litres. The maximum
capacity of the system shall be X species subject to the loading conditions given
a 25 watt, or greater, UV
below. The system must be fitted with
steriliser. Conditions All shellfish must be alive and healthy
before undergoing purification. Purification, without disturbance to shellfish,
must be for a minimum period of 42 hours once the correct
conditions of purification have been achieved.
The total volume of water in the system must be recirculated through the UV
lamps and evenly through the whole system at a rate of at least 20 litres
per minute. After each purification cycle the tank must be drained
down, without causing resuspension of sediment,
before shellfish are disturbed or removed. Seawater should only enter the system
via the operating UV system. Seawater should not normally be re-used for more
than 2 consecutive weeks. However, extended re-use up to a maximum of one
month is permitted where exceptional climatic or other circumstances dictate.
UV lamps must be changed after every 2,500
hours of use. A record of UV usage must be kept for this purpose. UV
lamps must be maintained free of slime and other substances which may impair
efficiency of

12. Conditions of approval
Bulk bins require a minimum
flow rate 6500L/h per bin for
250kg of mussels...
to keep oxygen > 5mg/L or 50%

13. Conditions of approval
Bulk bins require a minimum
flow rate 6500L/h per bin for
250kg of mussels...
substantial
pumping
costs

14. Can oxygen be maintained
above 5 mg/L at flows lower
than 6500 L/h?

15. Different Flows Regimes tested for 42 h
2500L/h
3000L/h
2500L/h
6500L/h
3000L/h
6500L/h

16. How we did it
Calculate the area of the hole to give a
flow of 3000 L/h or 2500 L/h
Q (m/s) = Area of the hole x
√(2xg force x height of the tank)
For each flow we used two tanks as replica

17. Mussels were harvested
and graded as usual

18. … and placed in the bins
12.6 ̊C

19. 12.6 ̊C

20. 30 min
90 min
7 hours
20 hours
24 hours
42 hours
Oxygen sampling

21. Top
MC
Middle
Bottom False Floor
FF
Drain

22. Results
Oxygen (mg/L) at 12.6 ̊C
9.0
8.0 * *
7.0
Oxygen (mg/L)
6.0
5.0
4.0
3.0
2.0
1.0
0.0
FF Bottom Middle MC Top Drain
2500 L/h 3000L/h 6000 L/h
6500 L/h

23. Results 7.8 mg/L
Oxygen (mg/L)
7.3 mg/L 7.5 mg/L
7.7 mg/L
7.1 mg/L 7.0 mg/L
Drain 7.6 mg/L
6.5 mg/L

24. Results 87 %
Oxygen (%)
81 % 83%
83 %
79 % 77 %
Drain 85 %
72 %

25. Can oxygen be maintained
> 5 mg/L at flows lower
than 6500 L/h?
Yes, 2500 L/h and
temperature <12.6⁰C

26. Transport with ice
What is the temperature?
Photo by Sara Barrento

27. Temperature during transport
Simulated transport
ICE
Logger

28. Temperature during transport
Simulated transport with ice
14.0
12.0 Outside box
10.0 Top
Temperature °C
Middle
8.0
6.0
4.0
2.0
0.0
00:00 01:00 02:00 03:00 04:00 05:00 06:00 07:00 08:00
Hours

29. Temperature inside the mussels
Simulated transport
Fake mussel Live mussel

30. Temperature C
2
4
6
8
10
14
12
10:32
11:19
12:06
12:53
13:40
14:27
15:14
16:01
16:48
17:35
18:22
Simulated 24h transport without ice
19:09
19:56
20:43
21:30
22:17
Temperature inside mussels
23:04
23:51
00:38
01:25
02:12
02:59
03:46
04:33
05:20
06:07
Live mussel
Fake mussel
06:54
07:41
08:28
09:15
10:02

31. Temperature inside mussels
Simulated 48h transport with ice and re-water at 11.7C
ICE
Re-water
11.7C
48h simulated transport

32. Temperature inside mussels
Simulated 48h transport with ice and re-water at 11.7C
18
16
14
12
Temperature °C
10
Bottom mussel
8
6 Middle mussel
4 Top mussel
2
Environment
0
10:00
00:00
06:00
12:00
18:00
00:00
06:00
12:00
18:00
00:00
11:00
16:00
06:00
11/02/2012 12/02/2012 13/02/2012 14/02/2012

33. Gaping out of water
40.0
Weight Loss %
32.5
30.0 26.7
20.0
10.0
1.8
0.0
45.5 mm 56.3 mm 68.3 mm
Mussel Length (mm)

35. vIDEO TRIALS

36. vIDEO TRIALS