Page 0060

Appendix 1

RSPCA welfare standards for farmed Atlantic salmon 53 September 2015

* indicates an amendment

Fungal infection

Infection with Saprolegnia fungus can result in serious disease conditions in fresh water stages of salmon

production, including the egg. Infection can be particularly severe at times when the fish's resistance to the

infection is low e.g. following vaccination, at low temperatures, and when maturing. Damaged fish are

particularly vulnerable when even very minor damage - removal of areas of mucus, scale loss, minor fin

erosion - allows the germination of fungal spores (which are ubiquitous in the fresh water environment),

which can lead to the development of serious skin, fin and tail lesions. The risk of fungal infection varies

between water sources, depending on the nature of the water body, water chemistry etc. and it is essential

that farmers are aware of the extent of the risk posed. There are no very effective treatments for

established fungal infection, and control must rest with minimising the risk of infection. Strict attention must

be paid to hygienic practices and the cleanliness and sanitation of equipment; accumulations of dirt, buildup

of biofilms, waste feed, faeces, and dead fish all act as reservoirs for fungus. Dead, damaged and

grossly infected fish and eggs must be removed from the water. All equipment and management

procedures, such as crowding and grading, must aim to minimise any damage. Priority should be given to

farming practices which are aimed at minimising handling the fish, including stocking policies, grading,

moving and transportation. Vaccination protocols must include methods of minimising subsequent fungal

infection including hygiene, vaccination technique, consideration of choice of vaccine, netting and handling,

and the use of 'wet' vaccination technique. Consideration should also be given to the use of nutriceuticals

prior to vaccination, and the prophylactic use of available anti-fungal agents post-vaccination.

Algae/Jellyfish blooms

Blooms of marine (and occasionally freshwater) phytoplankton (algae) and jellyfish (e.g. Solmaris corona)

have the potential for causing severe damage and heavy losses of farmed salmon. Algae may affect the

fish by producing toxins, by reducing oxygen levels at night and when they die off, and by being directly

irritant to the gills and skin. Similarly, jellyfish can be directly damaging by stinging, irritating and

accumulating within the gills, and by reducing water flows and oxygen levels. Indirect damage to fish can

occur as a result of stress and escape responses. Affected fish appear irritated, may 'porpoise' in the water,

go off their feed and show lethargy, skin damage and pale/damaged gills. Acute losses can occur due to

the toxic and/or oxygen depleting properties of the algae. Monitoring for these blooms must be carried out,

particularly during the period April-October, when blooms commonly occur. Monitoring should be carried

out using secci discs, dissolved oxygen logging, and by taking and preserving water samples for

examination. Appropriate procedures must be established to deal with a suspect algal/jellyfish bloom,

including stopping feeding, avoiding any stress to the fish, and the use of aeration systems/skirts.

Monitoring, area management agreements, early warning, and response must be integral to the long-term

management of blooms.

* Gill Disease

Gill Disease in Atlantic Salmon during the marine phase of their lifecycle is caused by a range of

pathogens, and includes conditions such as Amoebic Gill Disease (AGD) and Proliferative Gill Disease

(PGD). Recently, AGD has become more prevalent, and whilst the reasons for the proliferation of the

organisms causing the condition are not fully understood, certain factors such as water temperature,

salinity, smolt size and quality are key determinants contributing to the prevalence of the disease.

Treatments include bathing in hydrogen peroxide or freshwater. The timing and administration of these

treatments are key factors in terms of influencing the success of these procedures, as is the requirement to

make them as stress free as possible for the fish involved.

Index

  1. Page 0001
  2. Page 0002
  3. Page 0003
  4. Page 0004
  5. Page 0005
  6. Page 0006
  7. Page 0007
  8. Page 0008
  9. Page 0009
  10. Page 0010
  11. Page 0011
  12. Page 0012
  13. Page 0013
  14. Page 0014
  15. Page 0015
  16. Page 0016
  17. Page 0017
  18. Page 0018
  19. Page 0019
  20. Page 0020
  21. Page 0021
  22. Page 0022
  23. Page 0023
  24. Page 0024
  25. Page 0025
  26. Page 0026
  27. Page 0027
  28. Page 0028
  29. Page 0029
  30. Page 0030
  31. Page 0031
  32. Page 0032
  33. Page 0033
  34. Page 0034
  35. Page 0035
  36. Page 0036
  37. Page 0037
  38. Page 0038
  39. Page 0039
  40. Page 0040
  41. Page 0041
  42. Page 0042
  43. Page 0043
  44. Page 0044
  45. Page 0045
  46. Page 0046
  47. Page 0047
  48. Page 0048
  49. Page 0049
  50. Page 0050
  51. Page 0051
  52. Page 0052
  53. Page 0053
  54. Page 0054
  55. Page 0055
  56. Page 0056
  57. Page 0057
  58. Page 0058
  59. Page 0059
  60. Page 0060
  61. Page 0061
  62. Page 0062
  63. Page 0063
  64. Page 0064
  65. Page 0065
  66. Page 0066
  67. Page 0067
  68. Page 0068
  69. Page 0069
  70. Page 0070
  71. Page 0071
  72. Page 0072
  73. Page 0073
  74. Page 0074
  75. Page 0075
  76. Page 0076
  77. Page 0077
  78. Page 0078
  79. Page 0079
  80. Page 0080