Lecture 3

Question 1

Define stress in two points

Answer 1

The response of a organism to maintain normal function as a result of a chemical or physical force.
This response often places a high demand(energetically) on the organism, resulting in a weakened state.

Question 2

What is the optimal ranges for salmonids for
O2
pH
Total co2
NH3
Nitrite
Nitrate
Temperature

Answer 2

02- min 5-9mg/L best at 9-10mg/L (100% sat)
pH 6.5-8.5 Marine(7.6-8.2)
CO2 less than 10mg/l
NH3-less than 0.02 Marine 0.01mg/L
nitrite- 0.1mgél
nitrate- less than 1.0 mg/L
Temp: DO NOT EXCEED 2 degrees per day
Salmon- 3 to 20  best 10-14
oysters 4-25
Scallops 4-15 degrees

Question 3

What is gas supersaturation?

Answer 3

nitrogen level is too high and causes gas bubble disease

Question 4

What is Total Dissolved Solids and what is the optimal range?

Answer 4

All dissolved minerals in water and the optimal range is 80-110 ppm

Question 5

Which heavy metals are harmful to fish?

Answer 5

Zn, Cu, Hg often more toxic at a lower pH

Question 6

What is flow and exchange rate in a net pen and a tank?

Answer 6

TANK-.5 exchanges per min

Net pen- 10 to 60 cm per second

Question 7

Name 4 types of Culture procedure that can cause stress

Answer 7

1. Biosecurity awareness and protocols
2. Feeding mechanism( point source or uniform spreaders)
3. Stocking Density
4. Species differences

Question 8

Name 4 sources of stress from behavioral interactions?

Answer 8

1. Aggregate, solitary culture species
2. size grading
3. sexual maturation
4. Predators

Question 9

Name 4 sources of stress from Parasites and Pathogens?

Answer 9

1 Infection consumes energy
2 some fish do not feed when sick
3some pathogens and parasites are immunosuppressive
4Cortisol and their impairment to the immune system

Question 10

Mitigation of stress-( to reduce stress), Name 4 categories?

Answer 10

1. Avoidance- bad husbandry, feed quality, selection
2. Anaesthetics
3. Vaccine, immunostimulants
4. Broodstock management- resistant strains

Question 11

Name 2 immunity response types?

Answer 11

Non-specific - Not related to identity of invader
and Specific
- Depends upon RECOGNITION of an invader
-May be based upon prior exposure, results in an adatptive change
Both types work together

Question 12

How does cortisol effect the fish?

Answer 12

Impairs immune system function and uses considerable amount of energy

Question 13

Name 3 sources of immunity?

Answer 13

1. Innate(natural) immunity- Born with it -genetic
2. Acquired immunity-develop reisistance after exposure
3. artificial immunity- induced by vaccine or immunostimulant

Question 14

Difference between obligate and facultative?

Answer 14

Obligate- need a host to survive

Facultative-opportunistic -majority

Question 15

Difference between virulence and pathogenicity?

Answer 15

Patho- ability of an organism to produce disease

Virulence- severity of disease

Question 16

To cause diseases among a population a pathogen must ???

5 things

Answer 16

1. attach
2. Penetrate
3. Reproduce
4. Spread throughout host
5. Disperse to new hosts

Question 17

Describe obligate?

Answer 17

Need a host to survive

Question 18

Define Pathogenicity and virulence?

Answer 18

Ability of an organism to induce disease

Severity of disease