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sea_lice Flashcards

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1
Q

sea lice (sea lous sgl.) is a member of which family?

A

copepodes

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2
Q

what is sea lice?

A

ectoparaiste of many fish species.

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3
Q

on what does sea lice feed on? - what effect has that on the host?

A
  • mucus, skin and blood of fish
  • -> effect on:
  • host osmotic potential,
  • wounds open for infection
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4
Q

name the three sea lice genera

A

caligus
pseudocaligus
lepeophteirus

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5
Q

sea lice is harmful toards human health. true or false?

A

false

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6
Q

all sealice species are specific. true or false

A

false
caligus elogatus: >80 species
lepeoptheiurs salmonis: 3 genera

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7
Q

name two species of sea lice

A 
caligus elongatus 
lepeoptheirus salmonis (l. salmonis)
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8
Q

which sea lice species is the biggest threat for salmon AQC ?
and why?

A

L. salmonis

  • larger than c. elongatus
  • all year round infection
  • favors more sensitive skin areas (head, anal region)
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9
Q

what are the most common hosts for sea lice? L.salmonis

A

species from the salomonidae family:

  • salmo
  • salvelinus
  • oncorhynchus
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10
Q

sea lice: direct or indirect parasite?

A

direct

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11
Q

how many life stages does sea lice have?
name them!
L.salmonis

A 
8
planktonic stages: 
-nauplius 1
-nauplius 2
infective stages 
-copepodid
nonmotile stages 
-chalimus 1
-chalimus 2
(-former 1,2,3,4)
motile stages 
-preadult 1
-preadult 2
- adult male /adult female
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12
Q

the life stages can be divides into two life stages forms. name them?

A 
free-living stages  (nauplius 1&2 and copepodid)
parasitic stages  (rest....)
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13
Q

on what depends the developement time of nauplius 1 on 2?

L.salmonis

A

on temperature

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14
Q

what does postively phototactic mean? which stages of sea lice are postively phototactic?
L.salmonis

A

moving in the direction of light
–> daily vertial migration (rising during day, sinking at night)

  • nauplius copepode stages
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15
Q

what happens at copepode stage?

L.salmonis

A

attaching of the copepode on the fish

=infective stage

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16
Q

how long does copepode stage last?
- waht factor influences the time duration?
L.salmonis

A

2-14 days

-depending on water temperature

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17
Q

chemoattractants play an important role, when finding the “right” host. true or false
L.salmonis

A

true

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18
Q

the positively phototactic behaviour increases the chance to
L.salmonis

A

???

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19
Q

copepodes are better swimmer than nauplii.
true or false?
L.salmonis

A

true

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20
Q

what affcts survival and setlement of copepodes?

L.salmonis

A
  • local water currents
  • temper.
  • salinity
  • light intensity
  • chemoattractants
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21
Q

infection of sea lice has affects on behaviour of salmon. name some
L.salmonis

A
  • muscle twitches
  • rolls
  • bursts
  • jumps
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22
Q

what are the differences accroding moving on the host between the parasitic stages: chalimus stage (1 and 2) and predault stage?
L.salmonis

A

chalimus 1 and 2:
- attached to the host (through frontal filaments)
pre adult:
- louse is mobil –> moves around on the hosts body, prefers heas/anal regions

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23
Q

are female lice or male lice larger?

L.salmonis

A

femals (8-12 mm)

males (5-6 mm)

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24
Q

what does fecundity describe?

L.salmonis

A

mean egg number per string

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25
how many egg strings can female adult lice produce? L.salmonis
10-11 pairs
26
egg strings tend to be longer with.... | L.salmonis
... with higher fecundity
27
what is the fecundity values?
152 eggs
28
how long is the genration time of L.salmonis
depends on the temperature, the colder the longer | 4-9 weeks
29
at what lif stage does sea lice start eating? | L.salmonis
- nauplii 1&2, copepdodid: live on endogenous food storage--> non feeding chalimus= first feeding stage
30
how does the site selection of sea lice changes during the life stages? L.salmonis
chalimus : - dorsal, pectoral fins - around anus preadult and adult: - head - dosal surfaces - around anus
31
caligus elongatus: | generalist or specialist?
generalist ( >80 host species)
32
c elongatus is abigger problem for AQC in southern norway. true or false
fals: in northern
33
how many life stages has c. elongatus?
``` 8: nauplii 1&2 1 copepodid 4chalimi 1 adult ```
34
how many degree days does the copepodid stage lasts after infection? copepodid-chalimus
71
35
how many degree days does the chalimus stage lasts after infection? chalimus - adult
234
36
how is the fish affected by the lice c elongatus?
lice attaches and feeds on the fish ---> - physical damage : may lead to osmoregulatory failure and secondary infections
37
what is the deadly limit of a host from c. elongatus?
0.75 adult lice/g body weight smolt
38
death of grown salmon due to infection of c.elongtaus is rare. true or false?
true
39
what are clinical signs fro an infction by c elongatus?
- skin erosion, open wounds often on the head and back - ->- supepidermal haemorrhaging (bleeding under the skin) - -> erosin of skin
40
what influences the host suceptibility?
- host stress - nutrional status - immune system - genes
41
when was the first infection of sea lice in norway reported?
1960
42
sea lice is a natural parasite and was already found on fishes before industrial AQC. true or fals?
true
43
how salmon be transferred from fresh water systems to salom in cages?
through wild salmon which are infected. when they swimm past a salmon farm they can transfer the infection. also possible the other war around
44
where in norway could the highest infections of sea been observed?
møre and Romsdal | Nord-Trøndelag
45
in what stage is the sea lice first infective?
copepodid
46
what determines the infectio window of the sea lice?
the duration of copepodid life stage - depends on water temp.
47
on what deneds the distance a lice can travel?
on local water currents
48
on what does the dispersal of sea lice depend on?
temp. =time | water currents * time = distance
49
what is the traffic light system ?
norway coast divided into 13 zone. each zone will get a red/yellow or green light, dependning on the sea lice infection in this area
50
what is the goal of the traffic light system
reducte the impact of sea lice on wild salmon/caged salmon, by regulating biomass production in a zone.
51
how much of the population has to die due to lice infection that the zone is declared as a yellow zone? what is the consequence of the yellow light ?
10-30 % of the population no reduction /increase of biomass in the production zone
52
how much of the population has to die due to lice infection that the zone is declared as a red zone? what is the consequence of the red light ?
>30 % of the population reduce biomass in production zone
53
how much of the population has to die due to lice infection that the zone is declared as a green zone? what is the consequence of the green light ?
less than 10 % of the population increse biomass in production zone
54
how high have been the costs for sea lice in norwa in 2011? | how is the trend? how high in 2014?
2. 5 billion NOK trend: increasing 2014: doubled: ≈5 billion NOK
55
what is the limit for sealice per fish ? | why?
20 adult per fish, | due to the rapid increase of sea lice beyond this point
56
what are the 2 actions to combatt sea lice?
precuationary action | treatment actions
57
name some precautionary actions to combatt sea lice.
- cleaner fish - selective breeding - fallowing - vaccines - coordinated deployment of fish
58
name some treatment actions to combatt sea lice. | 4
1. )medical: 1. 1 oral or 1.2. bath 2) mechanical
59
what is "cleaner fish" action? what is positive, what is negative? increasing or decresing use?
using fishes that feed on the sea lice --> increasing use positive: no chemicals, natural negative: fear of transmitting disease, need cleaner nets
60
what speciesa res used as "cleaner fishes"?
lumpfish, wrasse species
61
on what depends "selective breeding" action? what isthe goal? how high were the susceptibility difference betw. salmon families?
depends on genetic variation in susceptibility to sea lice infection and the heritability of this. --> breeding for lice resistence 70%
62
name some oral treatment medicaments and the benefits and negatives of oral treatments.
SLICE EKTOBANN benefits: - easy to control dosage - less release in the environment - less stressfull for the fish negative: - can reduse appetite of the fish - expensive when fish is big and more feed is neeede.
63
name some benefits and negatives of bath treatments. | give some example for bath treatment substances.
benefits: - applied quickly - fisnished in one day negatives: - chemicals released into environment - need to control oxgen level --> add more stressfull for the fish - hydrogenperoxid - terapuline
64
what is MFMU?
medical free methods without handing
65
hat is MFMH?
medical free methods with handling
66
name some MFMH. what 3 need to be done to the salmon lice after the MFMH?
thermal heating of seaweter --> lice falls of - hosing the salmon (abspritzen) (turbulences in the water) - hosing+brushing freswater lice need to be collected and destroyed, to limit reinfection risk
67
name some MFMU treatment. | 3
cleaner fish lasers frehswater treatment in cage ()
68
how does the freswater MFMU treatemnt work?
affects iso osmotic balance of the lice (copepodids higher affected than preadult/adult stages)
69
name some preventive techological actions.
- lice skirts - snokel cages - submergable cages - semienclosed cages - electrical fences around the cage
70
what is the task force sea lice?
collaboration betw. most of the big salmon producing companies in trøndelag and NTNU

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