Aquatic environmental health Flashcards
(98 cards)
1
Q
Name 4 reasons other than food, why we farm fish?
A
- stocking recreational fisheries (UK’s number 1 participation sport).
- Diversity of species
- Pet trade
- Worldwide the most commonly kept companion animal (3rd most popular after dogs and cats in UK)
2
Q
What are farmed in the UK?
A
Both finfish and shellfish
3
Q
What are finfish?
A
Marine or Freshwater fish
4
Q
Name 4 types of farmed marine finfish?
A
Atlantic salmon (Salmo salar), cod, halibut, turbot
5
Q
Name 6 types of farmed freshwater finfish?
A
- rainbow trou (Onchorhyncus mykiss)
- Brown trout (Salmo trutta)
- Carp (Cyprinus carpio)
- Barramundi
- Tilapia
- , Pangasius
6
Q
Name 4 types of farmed shellfish?
A
- Mussels
- Oysters
- Cockles
- Clams
7
Q
Which two species are farmed the most in the UK?
A
Salmon and trout
8
Q
What does mussel growth rely on?
A
Natural plankton (no additional food is added to the water)
9
Q
What kind of habitat do mussels require?
A
A stable natural habitat to settle and grow into adult stock.
10
Q
Where do mussels grow?
A
In large beds either sub-tidally or between the tides.
11
Q
How are wild mussels harvested?
A
either towed dredge or hand-raking at low tide.
12
Q
How can mussel farming be carried out?
A
Either on the seabed or using suspended culture
13
Q
What is an area set aside for mussel growth called?
A
A lay.
14
Q
What legally happens in mussel cultivation?
A
A company or person is granted legal ownership of the mussels in a given area of seabed to enable mussel cultivation.
15
Q
What do mussels grow on in suspended cultivation?
A
Ropes and floats
16
Q
When are mussels harvested in suspended cultures
A
After 18-24 months.
17
Q
Where are most rope grown mussels?
A
Mainly Scotland, although also Cornwall.
18
Q
how are mussels grown in France?
A
On posts
19
Q
How are mussels grown in Spain?
A
On ropes suspended from rafts.
20
Q
name two benefits of well-managed mussel cultivation?
A
sustainable and low-impact.
21
Q
What do bivalve mollusc producers have to meet with?
A
EU’s End Product Standard.
22
Q
Name 5 requirements of the EU End Product Standard:
A
- Alive
- Fresh and in good condition
- Contain inter-valvular fluid
- respond to sharp tap
- Meet specified bacterial and toxin standards.
23
Q
What is required to setting up a fish farming site in Scotland rather than a formal license?
A
Permission from 3 institutions:
1 - planning permission from local regional council
2- marine license from Marine Scotland
3- discharge license from Scottish Environment Protection Agency (SEPA)
24
Q
What decides the MAB?
A
Maximal Allowed Biomass:
- environemntal concerns e.g. the capacity of local marine environment to accomodate the fish farm.
25
What is the range of MAB for various sites?
100-2,500 tonnes depending on site characteristics and geographic location.
26
Who decides the limit on production quantity in Scotland fisheries?
Competition Commission Authorities.
27
What is required for licensing aquaculture operations in the UK?
All new applications require planning application, as long as SEPA and Marine Scotland consents.
28
What happens when the planning permission is granted?
it is aligned to the Crown estate lease for 25 years.
29
What is the transition currently happening in Scotland regarding planning permission?
Transfer from the Crown estate to local regional councils which have a 25 year lease.
30
Where is 90% of manufactured feed going?
90% used for poultry, pig and ruminants.
31
What % of manufactured feed goes into aquatic farming?
4%
32
What is the predominant fish species globally?
Carp
33
Name two species of salmonids?
Salmon and Trout
34
Where are most of the fish farms in Scotland?
On the West coast and the Shetland islands.
35
Scotland is the 3rd largest salmon producer behind which other countries?
Norway and Chile
36
What are juvenile salmon called?
Smolts
37
At what age do smolts leave freshwater hatcheries and enter seawater cages?
6 months of age
38
When is salmon harvested and at what weight?
2 or more years (weight 2-3kg).
39
Where is most trout farmed?
In freshwater, usually river or spring water sources, however trout can also grow at sea.
40
What is a majority of trout farmed for and at what weight and age?
Table production (70%), weighing 300-400g at 7-9 months of age.
41
What are juvenille trout called and where are they produced?
Fingerlings - produced in hatcheries.
42
How many trout farms in the UK?
300
43
Why is all rainbow trout stock female in the UK?
This is because they can grow to the desired weight (300-400g) without reaching sexual maturity which would slow the growth rate and lose condition at spawning.
44
What happens to male trout in broodstock?
They are killed and stripped of milt.
45
When are females stripped of eggs and what happens with them?
Stripped of eggs whilst they are alive and they are fertilised with the milt.
46
What is triploidy and how is it achieved?
This is when there is an extra set of chromosomes therefore are sterile/no sexual maturity.
It is achieved by temperature or pressure shock.
47
Why is triploidy used?
When larger/heavier stock are required (beyond 400g) e.g. when trout continue to marine environments.
48
Name another example of triploidy?
When stocking brown trout into a river in order to avoid interbreeding with local brown trout which may reduce fitness of local fish.
49
Name the 6 key stressors in the aquaculture environment?
1. water quality - if poor, difficult to breath
2. crowding - if intense, cannabalism
3. Handling - stress and poor health
4. Disturbance - farm workers and wild animals
5. Nutrition - deficiencies can weaken immune system and affect development e.g. spinal deformities.
6. hierarchy - inability to form stable social hierarchy resulting in cannabalism.
50
Name 8 management approaches which will improve disease prevention?
1. Fish health management plans
2. Veterinary health plans
3. Biosecurity plans
4. Risk mitigation plans
5. contingency plans
6. Disinfection procedures
7. Surveillance schemes
8. synchronised zone/ area management
51
What are used commercially to reduce risk of health challenges during freshwater?
Vaccination
52
Name two benefits of vaccination.
Less disease and reduced medicine prescribed in the industry
53
Name 7 of the most important health risks for salmon?
1. Sea lice
2. Pancreatic Disease (PD)
3. Salmonid Rickettsial Septicaemia (SRS)
4. Infectious pancreatic Necrosis (IPN)
5. Heart and Skeletal Muscle Inflammation (HSMI)
6. Infectious salmon anaemia (ISA)
7. Gill Disease (GD)
54
How are sea lice controlled?
Through good husbandry and management practices and cleaner fish (wrasse and lump suckers). When necessary, can use medicines also.
55
What do sea lice feed on?
host mucus, skin and blood causing serious damage to skin and even death.
56
Is there a vaccination for sea lice?
No
57
What is Pancreatic disease caused by?
Salmonid Alphavirus
58
Where is PD present?
In Europe
59
What are the 4 clinical signs of PD?
1. reduced apetite
2. muscle and pancreatic lesions
3. lethargy
4. death
60
Is PD contagious?
yes
61
What species does PD infect?
Salmon and trout in seawater
62
How is PD controlled?
Mitigation practices
63
Is there a vaccine for PD?
Yes, where there is a risk
64
What is salmonid rikettsial septicaemia (SRS) caused by?
Piscirickettsia salmonis (Gram-ve intracellular bacteria)
65
Where has SRS been seen?
Mainly in Chile (biggest problem in Chilean salmon farming), but also Norway, Ireland and the UK.
66
What does SRS cause?
Lethargy, weight loss and death
67
What is SRS controlled by?
Vaccine and antibiotics.
68
What is the mortality rate due to SRS in Chile?
20% during 18 month saltwater production time.
69
What are the 10 clinical signs of SRS?
1. lethargy
2. Dark in colour
3. anorexia
4. Anaemia
5. mottled focal lesions within the liver
6. respiratory problems and swim near surface
7. haemorrhages of skin and small ulcers
8. kidney swollen
9. spleen enlarged
10. petechial haemorrhage on swim bladder and viscera.
70
Which antibiotic treats SRS?
Streptomycin
71
Is there a vaccine for SRS?
Yes, but new therefore effectivemess not known?
72
What is Infectious Pancreatic Necrosis (IPN) caused by?
the IPN virus which is contagious.
73
Is there a vaccine against Infectious Pancreatic Necrosis?
Yes.
74
What has contributed considerably to reducing IPN?
Selecting resistant fish
75
Where is Heart and Skeletal muscle inflammation reported?
In Scotland and Norway.
76
What are the symptoms of HSMI?
- reduced apetite
- abnormal behaviour
- low mortality
77
What is Infectious salmon anaemia (ISA) caused by?
A contagious virus
78
What does ISA cause?
Lethargy, anaemia and high mortality.
79
Are there vaccines for ISA?
Yes where ISA is a risk, but no licensed vaccines.
80
Where does ISA most commonly occur?
In hatcheries using sea-water.
81
What is a notifiable disease of salmon in the UK?
Infectious Salmon Anaemia because GB has disease free status.
82
is there any treatment for ISA?
NO
83
Name 5 causes of gill disease?
1. amoeba
2. bacteria
3. Viruses
4. Algae
5. jelly-fish blooms
84
What amoeba species causes gill disease?
Neoparamoeba perurans.
85
Name Environmental Impacts associated with aquaculture.
1. Water abstraction
2. Suspended solids/ organic loading
3. Reduced oxygen
4. Nitrogenous waste products (eutrophication)
5. Chemicals/drugs
6. Spread of enzootic pathogens (sea lice)
7. Introduction/movements alien species
8. Genetic contamination (reduced genetic ability in salmon due to interbreeding between farm and wild salmon).
86
Name 3 of the most important factors for water quality?
1. dissolved oxygen
2. dissolved solids
3. ammonia
87
What causes decreased oxygen dissolving into water?1
increased water temp.
88
Name 3 things which keep DO high?
1. mechanical aerators
2. air lines
3. liquid oxygen systems
89
Name two excretory products of fish?
ammonia and carbon dioxide.
90
What is the problem with water temp increases?
The level of free ammonia increases which is toxic to fish, as well as pH.
91
What is the recommended water flow?
14.3-21L/min/Ton
92
What is the Latin name for sea lice?
Lepeohtherius salmonis
93
How is lepeohtherius salmonis transmitted?
directly transmitted through plantonic larvae
94
What is the most significant parasitic parasite in America and Europe, costing £300 million a year?
Sea Lice
95
What is the lifecycle of sea lice?
1. Naupilus
2. copepodid
3. chaimus
4. pre-adult
5. adult
96
Fish farming is closely associated with what?
pathogen amplification
97
name 4 good practices to improve the environmental impact?`
1. careful water use - should be sent to settlement stations to reduce organic loading. this should be followed by water treatment and oxygenation.
2. Prevent escapes - regulations controlling the number of escapes from farming systems.
3. Appropriate pathogen control and prevention and post-outbreak management - vaccines cause antibiotics to decline.
4. Control of fish introductions - sterile shock (triploids)
98
What are the 3 biggest limiting factors for aquaculture?
1. disease
2. welfare concerns
3. environmental impact
