Transcript What Does Good Water Quality Look Like?

By: Michael Kaufman
Fisheries Technician
Water Quality Unit
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University of Pittsburgh at Johnstown
◦ B.S. Biology
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PFBC
◦ Fisheries Technician, Water Quality Lab
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Collect & receive water samples from 14 PFBC
fish hatcheries as defined by PA DEP National
Pollutant Discharge Elimination System
(NPDES) permits
Perform analyses on hatchery samples for
Carbonaceous Biochemical Oxygen Demand
(CBOD), Total & Dissolved Phosphorous (PO4),
Total Suspended Solids,
pH, Temperature, and
Dissolved Oxygen
Trout in the
Classroom &
Water Quality
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Fish live in water
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Fish receive life support from water
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Fish breathe in water (obtain oxygen from)
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Fish excrete in water
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Must maintain water quality at a level that
provides an environment conducive to fish
health and growth
Most disease problems can be avoided with
proper management of water quality
◦ Poor water quality can act as a stressor weakening
the immune system of the fish making them more
prone to infectious disease
◦ Poor water quality can cause massive mortality
The success or failure
of fish culture is
primarily determined
by water quality
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Dissolved Oxygen
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Temperature
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pH
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Nitrites/Nitrates
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Ammonia
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Chlorine
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DO is a relative measure of the amount of oxygen that
is dissolved or carried in a given medium such as water
Standard Units = milligrams per liter (mg/L), parts per
million (ppm), or Percent saturation (%)
Abundant in the atmosphere,
comprises 21% of atmosphere
Generally measured with a
dissolved oxygen probe
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Very soluble in water
Second most abundant gas in water (nitrogen
is first)
↑water temperature,
↓DO concentrations
↑ barometric pressure,
↑ DO concentrations
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Primary limiting factor for growth and fish health
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In general, minimum dissolved oxygen should be
≥ 100% of saturation or ≥ 5ppm (mg/L)
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As DO increases, metabolism increases
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◦ A trout uses five times more oxygen while resting at
80° F (26.7° C) than at 40° F(4.4° C).
As temperature increases, the dissolved oxygen
saturation level in the water decreases, while the
dissolved oxygen requirement for the fish
increases
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DO < 5.0, slows fish growth and increases
stress
DO < 1.0, can be lethal to fish
As temp. increases, the equilibrium amount
of DO in water decreases
Atmosphere
Oxygen diffuses
out of water
column
Oxygen diffuses
into the water
column
Oxygen > 100%
Saturation
Oxygen < 100%
Saturation
Water Column
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DO should not exceed 100% saturation for fry
and small fingerlings
D.O. supersaturation can cause mortality in
fry and small fingerlings
Supersaturation - refers to a solution that
contains more of the dissolved material than
could be dissolved by the solvent under
normal circumstances
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Influent DO – in our case the DO in the water
introduced to the tank
Fish density – more fish use more O2 & food and
create more waste
Temperature – water holds less O2 at higher
temps
Atmospheric pressure – water holds less O2 at
lower pressure
Excess organic matter that
leads to decomposition
Water velocity
Water clarity
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Normoxic - Having a normal oxygen
concentration; typically 20-21% in the
atmosphere
Hypoxic - reduced oxygen content in air or a
body of water detrimental to aerobic
organisms
Anoxic - a total depletion in the level of
oxygen or an extreme form of hypoxia
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Environmental Hypoxia leads to severe
mortality
Low O2 levels can act as a stressor and cause
chronic mortality and affect growth
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Lethargy
Congregation of fish near
air-water interface or near
water inflows
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Mouth open, gills flared
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High mortality after feeding
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Morts will have curved back and flared gills
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Little or no growth
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Low or no reproduction
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Ulcers/Tumors
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Susceptible to other diseases
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Decomposer organisms (mainly bacteria) also
consume oxygen in the system
Sometimes they consume oxygen faster than
it can be produced or replenished within the
system
A sudden increase in organic matter can
create a spike in decomposition activity which
can cause fish kills
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Brook trout require relatively high
concentrations of dissolved oxygen in water
compared to other fish and even other trout
species
Dissolved O2: Ideal dissolved oxygen levels
should be10-12 ppm, 8ppm is the absolute
minimum for developing eggs and alevins,
and 5ppm is the absolute minimum for fry
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Optimal dissolved oxygen levels for trout are not
well documented, but appear as the following:
◦ Rainbow trout: ≥ 7 mg/L at temperatures ≤ 15.0°C and
≥ 9 mg/L at temperatures > 15.0°C.
◦ Brown trout: ≥ 9 mg/L at temperatures ≤ 10°C and ≥ 12
mg/L at temperatures > 10°C.
◦ Brook trout: ≥ 7 mg/l at temperatures < 15°C and ≥ 9
mg/l at temperatures ≥ 15° C.
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Add aeration (additional airstones)
Lower water level so that your filter outflow
creates a mini waterfall
Check your water
temperature: decrease
slowly if needed
Stop feeding for a day or
two
Decrease fish density if low dissolved oxygen
levels persist
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How warm or cold the water is
Degrees Fahrenheit (°F) or degrees
Celsius (°C)
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Fish have specific temperature ranges
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Pathogens have specific temperature ranges
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Temperature can directly influence DO
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Temperature: Range for brook trout is 3372°F (0.6 -22.2°C), but Optimal is 48-52°F
(8.9-11.1°C)
Studies have determined that brook trout
cannot tolerate sustained water temperatures
exceeding 77°F (25°C) and prefer water
temperatures less than 68°F (22°C). Brook
trout are less tolerant of warmer water
temperatures than brown or rainbow trout.
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When temperature is too high or too low, fish can
become stressed
Avoid sudden changes in temperature
◦ Slight temperature changes can act as a
stressor (>1-2°F)
As temperature increases, metabolism increases
Prolonged exposure to extreme temperatures can
be fatal
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Symptoms
◦ Below 38°F (3.3°C) - Will suppress fish appetites and
slows digestion processes.
◦ Above 68°F (20°C) - Partial digestion of food. Water
holds less dissolved oxygen. Trout will gasp for
oxygen at water surface and crowd near the filter
outflow and/or chiller coil.
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Fixes
◦ Adjust temperatures accordingly using the chiller
unit and thermometer.
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At any given temperature the intensity of the
acidic or basic characteristic of the solution is
indicated by pH or hydrogen ion activity.
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pH is the negative logarithm of the hydrogen
ion concentration
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Expressed as Standard Units
(S.U.)
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pH scale is 0 to 14
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pH of 7 is neutral, below 7 is
acidic, above 7 is basic
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Generally measured using:
◦ a pH meter and indicators (buffers @ 4.01 SU
and 7.00 SU)
◦ Color wheel (universal indicator paper)
 Color charts needed to determine pH range
◦ Litmus paper
 Blue indicates basic
(7-14 SU)
 Red indicates acidic
(0-7 SU)
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Brook trout have evolved to be the most tolerant
of the trout species to acidic conditions. Adult
brook trout can tolerate pH levels as low as 5.0
pH: Ideal pH range for trout is 6.0 – 8.2
◦ pH outside this range negatively effects fish growth and
reproduction
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Extreme pH levels can be lethal to fish
◦ Levels of 4.0 and lower or 9.5 and higher are typically
lethal
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pH range of most of hatcheries is 7.2-8.0
Lower pH increases toxicity of many metals.
Water with a pH lower than 6.0 can cause
metals found in soil and rocks to dissolve
and suffocate and/or poison aquatic
organisms.
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Higher pH increases toxicity of ammonia
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pH of common liquids: bleach=12.7,
blood=7.3, milk=6.8, orange juice=4.2
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Fish can handle small changes in pH. They
are able to buffer by exchanging ions
between their internal (blood) and external
(water) environments. The most important
site of ion transfer are the gills
This ion exchange requires external Cl- for
internal HCO3-, and external Na+ for internal
H+.
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Blood acidosis (low pH) is corrected by
reducing the uptake Cl- by the gills and to
some extent increasing uptake of Na+. The
reduction in Cl- uptake thus reduces HCO3excretion, and the increase in Na+ uptake
increases the excretion of H+. Then net effect
is a compensatory increase and return to
normal blood pH.
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Mild cases - fish may become sluggish and
stay near the surface of the water.
Severe cases - trout will become excited,
jumping out of water, racing back and forth.
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Acute
◦ Tremors and hyperactivity
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Chronic
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Increased mucus production
Poor growth
Reproductive failure
Increased accumulation of heavy metals
Respiratory stress
Increased susceptibility to disease
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Gill, mucus cells and epithelial cells are
hypertrophic
Corneal damage
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Conduct partial water change. Know the source
water pH and aquarium pH. They should be within
+0.5 standard pH units to safely exchange the
water.
Temper pH slowly, using a commercial pH Up or pH
Down product sparingly and only after trying other
alternatives
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pH Up – increases pH of system
using Sodium Carbonate 10-19%
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pH Down – decreases pH of
system using Sulfuric acid <10%
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Ammonia is a compound of nitrogen and
hydrogen that can be found in the
atmosphere.
Produced from the putrefaction (decay
process) of nitrogenous animal and vegetable
matter.
Ammonia ions are also found in the
metabolic byproduct (animal waste) of
animals. In fish it is excreted directly into the
water.
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Reported in mg/L or ppm
Usually the second biggest contributor to
poor fish health and growth
Causes gill tissue hyperplasia
Decreases the ability of hemoglobin to carry
oxygen
Gill Hyperplasia
Normal Gill Tissue
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Maximum recommended levels for chronic
exposure:
◦ Salmonids - 0.0125 ppm un-ionized ammonia per
liter
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Ionized Ammonia (NH4 +)
◦ Upper limit for trout is 0.5 ppm
◦ Fish can be stressed at levels of 0.3 ppm
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Exceeding the upper limit can result in
reduced growth and damage to gills, liver and
kidneys
As pH increases, the toxicity of NH3 increases
◦ For example, a pH increase from 8.0 to 9.0,
increases the amount of NH3 by 10 times
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The interaction between WQ
parameters is critical
Excess food will increase
ammonia levels in your
aquarium. Do not overfeed your
trout.
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Immediate
◦ Conduct small (5-10 gallon) water changes. When
doing this use your siphon clean and take water
from the bottom of your aquarium. That is where
ammonia will settle most.
◦ Turn off filter and add a biological enhancement
agent or biological filter additive containing live
bacteria that improves the development of the
biological filter and helps clean a dirty aquarium.
Leave filter off for at least 2 hours before turning
it back on allowing biological agent time to work.
◦ Do not feed your trout for a day or two.
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Daily
◦ Feed smaller amounts of food
◦ Use a turkey baster to take out excess food 15-20
minutes after trout feed. This will prevent excess
water changes and targets areas where food tends
to accumulate.
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Long term
◦ Do NOT conduct too many water changes. Too
many water changes = aquarium not cycling
◦ Ensure that your good bacteria populations are
healthy.
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The biological
process that
converts
ammonia and
nitrite (both
toxic to fish)
into relatively
harmless
nitrogen
compounds
(nitrates).
 Stage
One – Ammonia Spike
◦ Ammonia is formed from all uneaten, decayed
food, and waste generated by metabolism in the
fish, where it is excreted directly into the water. It
breaks down to form ionized or unionized
ammonia.
◦ The ionized form, Ammonium (NH4+), is present
if the pH is below 7, and is not toxic to fish. The
unionized form, Ammonia (NH3), is present if the
pH is 7 or above, and is highly toxic to fish.
 Stage
Two – Decrease in
Ammonia & Increase in Nitrites
◦ Nitrosomonas bacteria colonize the filter and
derive all the energy they need for growth and
reproduction from converting ammonium
(NH4+) into nitrites. Nitrites (NO2) are highly
toxic to fish. Nitrites (NO2) destroy the
hemoglobin in the fish's blood and eventually
prevents the blood from carrying oxygen.
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Three – Decrease in
Nitrites & Increase in Nitrates
◦ Nitrobacter bacteria begin to colonize the filter and
feed on the nitrites (NO2) produced by the
Nitrosomonas bacteria. They convert the nitrites
(NO2) to nitrates (NO3), which are far less harmful to
fish. In doing this, they too begin to multiply their
numbers until most of the nitrites (NO2) being
produced are converted to nitrates (NO3).
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The byproducts, then, of the nitrogen cycle
is the carbon dioxide exhaled by the fish
and the nitrates produced by the bacteria.
Both of these are used up by some degree
by any aquatic plants present. The carbon
dioxide is used up by plants in the action of
photosynthesis, which produces oxygen
back into the water and the nitrates are
consumed by the plants as fertilizer to aid
their growth.
Ammonia
2NH4+ + 3O2
2NO2- + O2
Nitrites
Nitrites
2NO2- + 2H2O + 4H+ + energy
2NO3Nitrates
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Nitrites
◦ If nitrates present in aquarium (10ppm-40ppm): 0–2 ppm
◦ If nitrates NOT present in your aquarium: 0-0.25 ppm; any
higher will stress trout
◦ A cycled aquarium should have little to no nitrite readings
(0-0.5)
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Nitrates
◦ 5 – 40 ppm
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Ammonia
◦ If nitrates present in aquarium (10ppm-40ppm): 0-1 ppm
◦ If nitrates NOT present in your aquarium: 0-0.25 ppm; any
higher will stress trout
◦ A cycled aquarium should have little to no ammonia
readings
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Do not change aquarium water too often.
Changing will delay the growth of bacteria
needed to drive the nitrogen cycle and will
stress the fish.
◦ Only change when levels are extremely high. High
levels are needed in order for complete the nitrogen
cycle completely.
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Do not change filter media as that is where
the needed bacteria is located.
Do not overfeed.
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Acute:
◦ Hyperexcitability
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Chronic
◦ Enlargement of gill tissue in both cell size and
number
◦ Elevated blood pH
◦ Osmoregulatory disturbance
◦ Increased tissue oxygen consumption
◦ Reduced growth
◦ Increased susceptibility to disease
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Nitrite (NO2-) – high concentrations occur
after ammonia has peaked because nitrate
oxidizing bacteria (nitrate nitrifiers) require
time to become active
Trout will become stressed at levels above
0.15 ppm
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Levels above 0.55 ppm are lethal to trout
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Most levels in PFBC hatcheries are < 0.1 ppm
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High ammonium concentrations in alkaline
water inhibit nitrate nitrifiers
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Brown or tan gills due to nitrite converting
hemoglobin to methemoglobin
◦ Methemoglobin cannot transport oxygen as well as
hemoglobin
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Lethargy
Congregation near water surface and water
inflow
Should not be disturbed, any stress will cause
mortality
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Small water change, only about 5-10
gallons
A biological enhancement agent or
biological filter additive
Do not feed your trout for about a day or
two
Slowly decrease water temperature(48-50°F)
Conduct a static salt bath. This will reduce
stress on your trout and help fight off
infections
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Nitrate (NO3-) is the end product of nitrite
oxidation and nitrogen cycle
Must be removed through water changes or
denitrification
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Aka “Old Tank” phenomenon
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Typically not toxic to fish
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Problem gasses
◦ Nitrogen (primarily)
◦ Causes popeye/
exophthalmia
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Chlorine is typically what most
water authorities treat their
water with to rid public water
sources of harmful bacteria
and micro-organisms
Chlorine is lethal to fish at any
concentration and therefore
cannot be present in the tank
water
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How to remove chlorine from your water:
1.
Fill up two 5 gallon buckets.
2.
Allow the buckets to sit for at least 48 hours
before placing them into your aquarium
3.
While your buckets are sitting, you should
also occasionally stir the water to help
dissipate the chlorine more rapidly
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Other options: You can also use commercial
dechlorinators such as: Prime, AmQuel, AP
Tap water conditioner, and Aquasafe Plus
Chlorine (Total) Test
Kit, Model CN-21P,
Hach
Total Chlorine Test
Kit, Model CN-70T,
Hach
VWR: $40.25
VWR: $79.93
Pocket Colorimeter™ II,
Chlorine (Total), Kit
includes SwifTest™ DPD
Reagent Dispenser, Hach
VWR: $411.78
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Chloramines are another type of disinfectant
used by water authorities to kill harmful bacteria
in water. Ammonia is also added to municipal
water supplies to eliminate trihalomethanes
(carcinogen). Formation of chloramine occurs
through the reaction of chlorine and ammonia.
Chloramines are highly toxic to fish. Fish, unlike
humans and other animals, do not just swallow
water, they breathe it; therefore, the chloramines
enter directly into their blood stream, making it
difficult for their blood to carry oxygen.
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Chloramines, unlike chlorine, cannot be
removed by allowing your water to sit out for
48 hours.
Before using public water for your aquarium,
contact your local water authority to see what
they treat their water with.
Depending on what they treat the water with
will determine what you need to do.
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To remove chloramines, use a commercial
dechlorinator that specifically states that it
also removes ammonia.
If the label doesn't specifically mention that it
neutralizes ammonia, then don't depend on it
to safely treat water containing chloramines.
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Acute
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Difficulty breathing
Acute necrosis and asphyxiation
Extensive mucous secretion
Hypertrophy of gill epithelium
Mortality
Chronic
◦ Hemolytic anemia (abnormal breakdown of red
blood cells)
◦ Red blood cells composed of denatured hemoglobin
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An aquarium is a closed system, with no
natural water exchanges and limited space
for your trout population; as a result,
ammonia, pH, nitrite/nitrate levels and
carrying capacity can impact the health of
your trout. You need to make sure your
aquarium cycles and conduct water changes
only when your parameters indicate that you
need one.
Any Questions?