Economic Loss

Question 1

How can stress be caused in aquaculture?

Answer 1

Over crowding
Injury/Poor handling
Environmental Conditions beyond the physical norm

Question 2

What parameters can you adjust to control the environment?

Answer 2

• Temperature,
• Salinity
• Dissolved Oxygen
• pH
• Ammonia

Question 3

Environment Example: With bitter crab disease, what can be done to minimise infection?

Answer 3

• virulence of hematodinium spp declines at low salinities

- Increase temperature (evidence suggests disease is more prevalent during winter months

Question 4

Environment Example: With Dermo disease, what can be done to minimise infection?

Answer 4

• Perkinsus marines
• disease more prevalent in summer months so low temperatures and salinities would reduce virulence
• low temp and salinity also favours plasma Lysozyme production which can counteract pathogen

Question 5

Environment Example: With Aeroccoccus viridians, what can be done to minimise infection?

Answer 5

• lobsters infected
• store lobsters at low temperatures (can only go so low as the lobsters take longer to grow so high aquaculture costs
• HOWEVER potenially ends up in physiological niche of another parasite at low temperatures - ANOPHYROIDES HAEMOPHILIA (3degrees)

Question 6

What does the term pathogenic evolution mean

Answer 6

applying selection pressures to the pathogenic organism

Question 7

What does SPF mean?

Answer 7

Specific pathogen free

Question 8

Who/What monitors shellfish beds

Answer 8

CEFAS

Question 9

What does CEFAS stand for?

Answer 9

Center for environmental, fishery and aquaculture science

Question 10

What is a cheap and practical solution to minimise infection between farms?

Answer 10

Restricted movements - monitored by CEFA or FRS

Question 11

What term is used to describe measures which prevent disease in aquaculture

Answer 11

Biosecurity

Question 12

What ways can you control the host?

Answer 12

• Reduce Stock (less stress)
• Mixed Culture
• Immunostimulents
• Genetic manipulation
• Selective Breeding

Question 13

Give some examples of Immunostimulents

Answer 13

• beta-1,3-glycans from yeast

- Peptidoglycans

Question 14

What are some limitations of using immunostimulants

Answer 14

• Don’t seem to work against viruses
• effects on immune system are short lived
• effects are not always reproducible in situ
• effects not always confirmed by scientists
• reduced growth rate

Question 15

What does SPR stand for?

Answer 15

Specific Pathogen Resistant

Question 16

Give an example of and SPR organism

Answer 16

SPR shrimp = ‘Super Shrimp’

• Have been selectively bred
• Shrimp are immune to IHHNV (Infectious hypodermic and haematopoietic necrosis virus)

Question 17

What are the limitations of Selective Breeding

Answer 17

• Aquiring survived individuals (often discarded with the rest of infected stock)
• Inbreeding depression

Question 18

What ways can you control pathogens?

Answer 18

• Fungicides
• Chemotherapeutants
• Antibiotics
• Probiotics

Question 19

What are the concerns for using antibiotics?

Answer 19

• usage has declined in past years
• Antibiotic resistance
• Residuals in harvested stock - food safety

Question 20

What is meant by the term veterinary cascade?

Answer 20

Vets have a code of conduct to conserve species and animal lives
- Usage of antibiotics is frowned upon in aquaculture communities but vets can use them if it is the only thing that can help

Question 21

What is the difference between pre- and probiotics?

Answer 21

Prebiotics - chemicals which create optimal conditions for bacterial growth
Probiotics - Actual bacteria