Aquatic Systems Flashcards

1
Q

What are the top 5 parameters of water quality?

A
  1. Temperature
  2. Dissolved Oxygen
  3. pH
  4. Ammonia
  5. Nitrites and Nitrates
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2
Q

How do open and closed water systems differ?

A

Open (pens, raceways)
- reliable water source
- excellent water quality
- can hold high stocking densities

Closed (ponds, aquariums)
- less total water required
- better control of the system
- can only hold a limited stocking density

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3
Q

What products do fish excrete?

A
  • Ammonia (1º waste product/excreted through their gills)
  • CO2
  • Solid & liquid waste
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4
Q

Describe the nitrification process

A
  1. Fish metabolize protein into ammonia & excrete thru gills. Ammonia = toxic.
  2. Aerobic bacteria on biofilter consume ammonia and produce nitrite. Nitrite = toxic.
  3. Aerobic bacteria on biofilter consume nitrite and and produce nitrate. Nitrate ≠ toxic unless in high levels.

Biofilter medium can take 6-8 weeks to accum. adeq. nitrifying bacteria

As a biofilter cycles, ammonia will rise until sufficient nitrifying bacteria are present to consume the ammonia and convert it to nitrite. Ammonia levels will then begin to decrease while nitrite levels increase. Nitrite levels will continue to increase until sufficient bacteria are present to consume the nitrite and convert it to nitrate. Unless many plants are present, nitrate levels will rise slowly until a water change is performed.

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5
Q

Ways to decrease water temperature

A

provide shade; increase water flow

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6
Q

Your fish are gulping at the surface, appear lethargic, and have increased ventilation efforts. How do you address the problem in an open vs. closed system?

A

Low dissolved oxygen levels (warm temperatures, animal/plant respiration, organic decomposition)
- Open system: increase water flow, add in a water agitator
- Closed system: air stone

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7
Q

Average DO requirement for fish

A

Minimum of 5ppm

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8
Q

pH ranges:
1. FW
2. SW
3. Fatal levels

A
  1. FW = 6.8-7.8 (7.2)
  2. SW = 7.8-8.6 (8.2)
  3. Fatal levels = 4.0 & 11.0
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9
Q

FRESHWATER Water Quality Parameters

The ideal
- ammonia
- nitrite
- nitrate
- salinity levels in aquatic systems

A

FRESHWATER Water Quality Parameters
- ammonia = < 0.02ppm
- nitrite = < 0.10ppm
- nitrate = < 100ppm
- salinity = 0ppt

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10
Q

MARINE Water Quality Parameters

The ideal
- ammonia
- nitrite
- nitrate
- salinity levels in aquatic systems

A

MARINE Water Quality Parameters
- ammonia = < 0.02ppm
- nitrite = not applicable
- nitrate = < 100ppm
- salinity = 32ppt

Nitrite ions compete with Cl- ions -> high [NaCl] decr. Nitrite uptake

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11
Q

3 major functions of gills

A
  1. Respiration (gas exchange)
  2. Excretion (ammonia)
  3. Osmoregulation (ion-mineral balance)
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12
Q

Name of strucure on the gills where respiration (gas exchange) occurs

A

Lamellae

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13
Q

Difference b/w freshwater and saltwater fish OSMOREGULATION

A

Osmoregulation = how fish maintains homeostasis of salt ions and water

Freshwater = constant water gain and salt loss
- [salt] in blood is GREATER than [salt] in water -> salt constantly moving OUT
- water is constantly moving IN
- constantly reabsorbing salts from urine and excreting dilute urine in order to preserve salt ions
- never drink water

Saltwater = constant water loss and salt gain
- [salt] in blood is LESS than [salt] in water -> salt constantly diffusing IN
- water constantly moving OUT
- constantly drink water to stay hydrated -> excess uptake of salt ions present in saltwater -> excess actively excreted out thru gills

Ions: high->low, Water: low->high

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14
Q

Pollution and low oxygen are __?__ stressors

A

Chemical

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15
Q

Capturing and handling are __?__ stressors

A

Physical

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16
Q

Stimuli evoking a startled response (sound; presence of predator) are __?__ stressors

A

Perceived

17
Q

What are the…
1º, 2º and 3º stress responses in fish?

A

1º = Blood
- increase in hormone levels

2º = Tissue
- metabolic changes (incr. in BG or lactate)
- immunological changes

3º = Population
- changes in entire population’s health (growth, repro, disease resistance)
- behavioral changes (feeding; aggression)

18
Q

What influences the degree of environmental stress on fish health? (3)

A
  1. Duration
  2. Onset (acute vs. chronic)
  3. Absolute degree
19
Q

Most important important environmental stressor to fish?

A

Water quality!!

20
Q

5 clinical signs of disease in fish

A
  1. changes in behavior
  2. decrease in appetite/ravenously hungry
  3. changes in coloration
  4. development of external lesions
  5. increased morbidity and mortality
21
Q

Temperature ranges for cold- vs. cool- vs. warm-water fish

A

Cold = 32-55ºF
Cool = 50-70ºF
Warm = >70ºF