Fish health 1 Flashcards

1
Q

what are the infectious agents?

A

parasites and pathogens

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2
Q

how do parasites and pathogens differ in trophic level strategy than other members of the marine community?

A
  • predators: affect all life stages

- decomposers: affect non-living organisms

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3
Q

Pathogens- what are they?

A

microparasites, build up in numbers (asexually) from a single infection events
(ie: virus, bacteria)

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4
Q

Parasites- what are they?

A

macroparasites, recruit to a host and grow (sexually) (ie: sea lice)

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5
Q

Parasitoids-

A

kill host as part of their development (ie: bacteriophage)

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6
Q

what do parasites/pathogens require to complete their life cycle?

A
  • must recruit a new host

- macroparasites may need several new hosts

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7
Q

what are the three main routes of transmission?

A

1- free living stage

2-vectors

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8
Q

describe free living stage

A
  • usually an infective stage that exits host through wound or orifice
  • usually non-feeding
  • short-lived (virus)
  • persistent-dormant-nematode egg
  • passive(egg) and actively mobile stages to transmit between hosts
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9
Q

describe vectors

A
  • some parasites require a vector to move the infective stage from host to host.
  • ie: infective stage circulates in vector blood system (leeches, sea lice)
  • parasite might further develop in vector host
  • ie: some viruses, worms, trypanosomes.
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10
Q

what percent of known metazoan spp are parasitic?

A

40% (prob underestimate)

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11
Q

what is the rough proportion of parasitic spp to free-living spp?

A

at least as many

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12
Q

how is knowing the diversity of parasites and pathogens important?

A
  • diversity of parasites represent a variety of differerent trophic level strategies and life cycles
  • helpful in making predictions about potential effects of parasites on marine ecosystems
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13
Q

name some factors which can effect infectious disease dynamics

A
  • warming water temperatures
  • acidification
  • eutrophication
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14
Q

what are some factors to consider when making predictions about the effects of environmental variables on infectious diseases?

A
  • environmental effect on an individual host and its population density
  • environmental factors have non-linear effects on phisiological processes of both hosts and parasites
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15
Q

flashcard notes ended

A

on slide 10/41

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16
Q

how can stress caused by environmental conditions be a good and bad thing?

A
  • decreasing env. conditions can/will cause stress to hosts
  • increased stress: increased susceptibility to infection and parasite numbers increase
  • increased stress: cause premature host mortality, reduces disease transmission, decrease incidence of disease
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17
Q

How do environmental factors have nonlinear effects on physiological process of hosts and parasites?

A
  • each spp. has OPTIMAL range of light, oxygen, pH, etc
  • shifts in particular environmental variables can disrupt the ability of a well adapted parasites to infect hosts.
  • some parasites can adapt to changing conditions or some are extirpated from the ecosystem
  • other infectious agents are better suited to the changing conditions and be favored resulting in novel host-parasite interactions and combinations.
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18
Q

what direction of shifts in distribution of infectious diseases will warming likely lead?

A

latitudinally

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19
Q

Perkinsus marinus (what is it)

A

protozoan parasite of several marine organisms, severely affects oysters.

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20
Q

how is perkinsus marinus affected by increased weather?

A
  • proliferates at high water temperatures and high salinities as usually seen in river estuaries during drought conditions
  • increased water temp along eastern sea board they are spreading rapidly
  • now found up to NS
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21
Q

regional warm temperature anomaies have now been correlated with what in the caribbean and pacific?

A

high coral disease prevalence

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22
Q

what disease is the black abalone along the cali coast to mexico affected by?
what does it cause?
what causes it?

A

withering syndrome/abalone wasting disease.

  • caused by a rickettsia like organism (RLO)
  • lethargy, retracted visceral tissue, atrophy of the foot muscle
  • although abalone can survive it at low densities and normal conditions, increased VARIABILITY of water temps in intertidal zones increase suceptibility.
  • mass mortalities as mean water temperatures increase.
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23
Q

how does increased OA affect pathogens?

A

growth of Vibrio increased by 13% in lower pH water

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24
Q

how can nutrients promote infectious diseases?

give an example

A
  • increased nutrients increase productivity and host densities, increase parasite/pathogen transmission efficiency
  • black band disease on corals
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25
Q

how does variable environmental factors affect parasites/pathogens similarly/differently from their hosts?

A

similar: variable factors affect them too.
different: their RESPONSES are different
- parasite success are constrained by the environment because their hosts are constrained by the environment

26
Q

how are parasite/pathogen niches affected by variable environmental factors?

A

P/P have niches as do free living spp, but changing conditions can push them outside their niche space
-this creates opportunities for other pathogens/parasites to exploit the available resources and hosts.

27
Q

what are key advantages to studying parasite communities?

A
  • host habitat: parasite community boundary is well defined

- easy to obtain large #s of hosts: replicates easy to obtain

28
Q

what are some distinctive parasite fauna

A
  • generalist and specialist parasites

- higher proportion of trematodes and acanthocephalan parasites than other vertebrates

29
Q

same some ecological traits of hosts which have been linked to parasite communities in fish

A
  • size and age
  • habitat
  • trophic level
  • schooling behaviour
  • pop’n size and density
  • geographic range
  • latitude
  • depth
30
Q

how does size/age of host affect ParaComm?

A

affects the amount of time that a host has been able to accumulate parasites (large fish have more abundant and diverse parasites)

31
Q

how does habitat of host affect ParaComm?

A

pelagic fish have fewer parasites than benthic fish (2D/3D)

32
Q

how does geographic range of host affect ParaComm?

A
  • latitudinal gradient that leads to high diversity near the equator
  • this pattern hold true for ectoparasites of fish but not for helminth communities which require life stages within the host
33
Q

how does depth of host affect ParaComm?

A

deep sea fishes tend to have fewer parasites than other fish, perhaps due to lower fish DENSITIES

34
Q

how is the bacteriophage and bacteria relationship similar to the host-predator prey cycle in mammals?

A

-increased ocean upwelling/increased bacterioplankton/increased phage production/bacterial ppl decrease.

same concept with mammals.

35
Q

name some conditions where parasites reduce or regulate host ppl or density

A
  • bacteriophages/bacteria: phages most abundant where hosts are abundant
  • increased disease prevalence to decrease surging host ppls.
36
Q

how are increased disease prevalence decreasing surging host ppls?

A
  • ie:
  • increase in sea urchin ppl due to reduction in urchin predators
  • urchin epizootics cause massive ppl declines and suggest the diseases actually regulate ppl size where natural predators are rare or overfished
37
Q

read slide 28-31 about otters

A

might be a question on it

38
Q

name some mass mortalites caused by infectious diseases

A

1930s: 90% of eel grass on both coasts affected by slime mold-like
protist
-mass urchin (diadema antillirum) die-off in the 80s, suspected fungus, 95% ppl.
-1995: fungus attacked sea fans, 20-90% of fans died, 50% of caribbean fans lost.

39
Q

Caribbean Elkhorn and Staghorn coral have been in wide decline due to what?

A
  • white band disease (Vibrio)

- white pox disease

40
Q

how can para/paths alter entire communities?

A
  • increase/decrease coexistance among competitors
  • drive host densities to lower levels
  • change behavior of dist’n of host dynamics within the community, especially w/ keystone spp.
41
Q

slide 35/41. density dependent transmission.

A

talk it over, ask questions. can’t figure it out!

42
Q

how can infectious diseases have indirect effects on coexistance and competitions withing a community?

A
  • INTERACTIONS among COMPETING SPP can be effected by infectious disease.
  • infectious diseases can DECREASE COEXISTANCE when there is variation in tolerance of infection among competing host spp.
  • less tolerant spp become at a DISADVANTAGE: more tolerant spp will outcompete for resources.
43
Q

give an example on indirect effects of infectious disease to ppl diversity

A

eelgrass beds were infected by wasting disease

  • loss of nursery habitat for fish and waterfowl
  • extinction of eelgrass limpet
44
Q

break down the percentages of infectious diseases which affect fish

A

25% viruses
34% bacteria
19% protists
18% metazoans

45
Q

how does trophic level affect ParaComm?

A

some parasite spp are only foundin one host of a specific trophic level. when these parasites are found in other non-host spp there may have been a change in the environment or host

46
Q

how does schooling behavior affect ParaComm?

A

parasites with little need to use vectors, free swimming stages as new hosts in very close proximity at all times.

47
Q

whats the relationship between oystercatcher and littleneck clams?

A
  • oystercatchers eat clams
  • oyster catchers are host to adult trematodes
  • poop eggs
  • trematodes attack clam foot, prevent them from burrowing away from the birds
  • prevent the clam populations from exploding
48
Q

what are some essential information to consider when managing a fishery

A
  • biology of the fish being harvested/exploited
  • understand how the fishery interact with the fish spp being exploited (capture techniques)
  • how the fish respond to exploitation
  • how other spp share their habitat and how the local ecology will respond with exploitation of one spp
49
Q

different management approaches must be taken depending on whether the fish are:

A
  • territorial
  • only exist in discrete patches with little exchange between similar patches found regionally
  • exist in patches but DO have exchange with similar patches through mechanisms such as larval dispersion
  • are the fish PELAGIC and have a uniform distribution which may or may not change with season?
  • –> all affects both the SAMPLING and MANAGEMENT decisions for a fishery
50
Q

how are fish generally managed? (large scale)

A

as a stock or population, not as a species

51
Q

Depending on habitat-type, different stocks may respond differently to exploitation due to differences in

A
  • food availability
  • predators present in the area
  • primary productivity
52
Q

who is the current minister of fisheries and oceans?

A

Hunter Tootoo

53
Q

TAC

A

total allowable catch

  • management approach
  • fish scientist assess the fish stocks and suggest a MAX amount of fish that should be caught to keep the stock stable or in equilibrium
  • then FISH MANAGERS decide if the suggested TAC is politically acceptable and assign the fishery TAC
54
Q

EEZ: what is it and what is the objective of it

A

economic exclusive zone

-enhance the conservation and economic management of world marine fishery resources

55
Q

what is one of the most dramatic and depressing examples of fishery management failure under the EEZ regime

A

Grand Banks of Newfoundland groundfish.

56
Q

what are the causes of the cod fisheries crash?

A
  • before the EEZ was in place the grand banks were being harvested by global fishery efforts, already depleting stocks
  • equipment and technology increased, increased volume landed
  • this increased from small limiting vessels to supertrawlers with high tech fish finding equipment
57
Q

what did the east coast fishermen replace the cod with as their targeted spp?

A

queen crab = snow crab, northern shrimp, other invertebrates

58
Q

in 2010, how much of the original stock of cod had recovered?

A

10%

59
Q

what is the largest certified sustainable fishery in the world?

A

alaskan pollock

60
Q

what amount of the world’s fisheries has been underestimated over the last 60 years?

A

more than 50%

61
Q

what is the hydra effect?

A
  • where a higher death rate in a particular species ultimately increases the size of its population
  • adverse changes in the environment that reduces the growth rate of a population may ultimately lead to greater numbers.
62
Q

how can some fishing activities increase infectious diseases?

A
  • bitter crab disease
  • small amount of crab meat infected will contaminate the entire lot.
  • when crabbers notice an infected one they huck it overboard, essentially spreading the disease to new areas