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Center for Research Animal Resources Workshop Fish Health Management

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Presentation on theme: "Center for Research Animal Resources Workshop Fish Health Management"— Presentation transcript:

1 Center for Research Animal Resources Workshop Fish Health Management
Paul R. Bowser Aquatic Animal Health Program Department of Microbiology and Immunology College of Veterinary Medicine Cornell University Ithaca, New York

2 Workshop Overview Water Quality Management – General Comments
Important Water Quality Parameters Monitoring Water Quality Aquarium Systems Aquaculture Systems Fish Physiology Basics

3 Workshop Overview (cont.)
Disease Diagnosis – how you can help us better help you Your “Fish Room”

4 Water Quality Management –General Comments
Water as a “Universal Solvent” Will dissolve a lot of substances Oxygen Toxins

5 Water Quality Management –General Comments
Specific gravity Changes with water temperature In general: as T ↑ Specific Gravity ↓ Maximum at 4C Importance: uniformity (you don’t want water with different specific gravity in your fish holding system) This is mostly a problem in a large (i.e. pond) system

6 Water Quality Management –General Comments
Hardness Amount of divalent cations Primarily Ca++ and Mg ++ Hardness can have interactions with other water quality parameters and disease treatment compounds Want hardness at approximately 100 mg/L (as equivalent CaCO3)

7 Water Quality Management –General Comments
Alkalinity Carbonate, Bicarbonate and Silicate Important in providing buffering capability Capability to resist a change in pH Stability of pH is desirable

8 Water Quality Management –General Comments
pH Log of the inverse of the hydrogen ion concentration Log function Freshwater: pH = 7.0 – 7.2 Saltwater: pH = 7.8 – 8.0 Ideal (in general) stay near the normals

9 Water Quality Management –General Comments
Specific heat The amount of energy it takes to change the temperature of a given substance Water has a high specific heat It takes a lot of energy to change the temperature of a given volume of water Water temperature can be changed slowly

10 Important Water Quality Parameters
THE WATER SOURCE IS OF PARAMOUNT IMPORTANCE Well water Spring water – devoid of living organisms, especially potential vectors of fish pathogens Surface water – wild fish are a source of pathogens filter UV treat Ozone treat

11 Important Water Quality Parameters
Water Temperature The ideal for the species An acceptable range for the species Tropical fish Cool water fish Cold water fish

12 Important Water Quality Parameters
Dissolved Oxygen As water temperature ↑, O2 carrying capacity ↓ Temperature O2 at 100% Saturation (mg/L)

13 Important Water Quality Parameters
Dissolved Oxygen As water temperature ↑, O2 carrying capacity ↓ Temperature O2 at 100% Saturation (mg/L) NOTE: A fish at 25C deals with 8.25 ppm DO; we deal with 20 per cent (parts per hundred)

14 Important Water Quality Parameters
Dissolved Oxygen Note: As Temperature ↑ DO at 100% Saturation ↓ BUT: As T ↑, O2 requirement of FISH ↑ Problem: Not enough O2 at higher water temperature to support the needs of the FISH

15 Important Water Quality Parameters
Nitrogenous compounds Ammonia (NH3/NH4+) ↓ Nitrosomonas Nitrite (NO2) ↓ Nitrobacter Nitrate (NO3)

16 Important Water Quality Parameters
Nitrogenous compounds Ammonia ↓ Nitrosomonas Nitrite (NO2) ↓ Nitrobacter Nitrate (NO3) The reaction is aerobic The biological filter must not become anaerobic

17 Important Water Quality Parameters
Nitrogenous compounds Ammonia (NH3 + H NH4+) High pH High T Nitrite Nitrate NH3 (unionized ammonia) is the toxic form A greater % of total ammonia is in the unionized form at higher pH and temperature pH has the greater impact

18 Important Water Quality Parameters - Ammonia
Temperature (C) ______________________________________________________________ pH % of Total Ammonia in Unionized Form pH had a dramatic impact on % of total ammonia that is in the unionized form

19 Important Water Quality Parameters - Ammonia
Temperature (C) ______________________________________________________________ pH % of Total Ammonia in Unionized Form pH had a dramatic impact on % of total ammonia that is in the unionized form

20 Carrying Capacity 12” 12” 30” 12” 30” 12”
i.e. W = 30” L = 12” W X L = 360 in2 FW Tropical: (L X W)/12 = 30 (“inches” of fish) FW Coldwater: (L X W)/30 = 12 SW Tropical: (L X W)/48 = 7.5 A SW Tropical tank can only hold ¼ the fish biomass as a similar FW Tropical tank.

21 Carrying Capacity 12” 12” 30” 12” 30” 12”
A SW Tropical tank can only hold ¼ the fish biomass as a similar FW Tropical tank. WHY THE DIFFERENCE? AMMONIA and pH Saltwater is buffered at 7.8 – 8.0 Freshwater is buffered at 7.0 – 7.2 Almost 10X the ammonia will be in the toxic unionized form

22 Important Water Quality Parameters
Chlorine Chlorine can be highly toxic to fish Found in municipal water Need to remove: Sodium thiosulfate Allow Chlorine to dissipate with time Aeration/agitation will speed release

23 Important Water Quality Parameters
Other potential toxicants Wide variety of compounds pesticides fertilizers pollutants (may have BOD) gases smoke etc………….

24 Monitoring Water Quality
Common sense This is not a “one size fits all situation” You should evaluate your system and develop a rational schedule for water quality monitoring.

25 Monitoring Water Quality
Water Temperature Goal to maintain at the optimum for the species unless the protocol specifies otherwise Rapid water temperature change is a stressor A rapid 5C water temperature change suppressed the immune system of channel catfish for 4-6 weeks. Monitor daily unless you expect frequent temperature changes

26 Monitoring Water Quality
Dissolved Oxygen Ponds will have a diurnal DO pattern 6am 6pm 6am Diurnal nature of DO is due to photosynthesis and intensity of sunlight Need to monitor DO at daily “low point” (early morning)

27 Monitoring Water Quality
Dissolved Oxygen Raceways with gravity flow Agitation and aeration provides DO Tanks Air pumps Air blowers If you have a choice, don’t use compressors Dissolved Oxygen should not be a problem in raceways and tanks due to movement of water and/or mechanical devices.

28 Monitoring Water Quality
Total Ammonia and pH Ammonia (NH3 + H NH4+) High pH High T New Tank Syndrome (first 30 days) NO2 NH3/NH4+ NO3 Conc. 30 days Time (days)

29 Monitoring Water Quality
Nitrite Ammonia → Nitrite → Nitrate Toxic (conc. as low as 0.5 mg/L) Brown Blood Disease, Methemoglobinemia Nitrite oxidized hemoglobin (brown color) The oxidized hemoglobin can’t carry oxygen Signs of respiratory distress

30 Monitoring Water Quality
Hardness and Alkalinity Interactions with Tx compounds CuSO4 and alkalinity Copper sulfate toxicity increases as Alkalinity decreases

31 Aquarium Systems Dissolved Oxygen Oxygen Air stones
Air/water interface Utilizers of oxygen Producers of oxygen Aquaria: mechanical Ponds: photosynthesis Water Circulation

32 Aquaculture Systems Temperature Optimum for fish
Interactions between temperature and DO Metabolism increases Oxygen requirement increases Food intake increases Temperature as a Stressor Elevated Temperature Temperature Change High Lethal Opt. OK Low

33 Aquaculture Systems Filtration: Biological Mechanical Chemical
Outside Power Filter: mechanical, chemical, biological filter Filtration: Biological Mechanical Chemical Undergravel Filter: biological, mechanical filter

34 Aquaculture Systems Filtration
The need for filtration – Required for a closed system Types of Filtration Mechanical – remove particulate matter Biological – performed by bacteria Nitrosomonas, Nitrobacter – detoxify N-compounds Capability/Capacity: a function of surface area of the filter medium Chemical – remove small molecular weight compounds Disease Tx compounds

35 Aquaculture Systems Filtration Types of filters Chemical:
Mechanical: foam, filter floss, gravel (1/4-1/8” dia.) Biological: create a large surface area to be colonized by the Nitrosomonas and Nitrobacter foam, floss, gravel Chemical: activated carbon dolomite zeolite ion exchangers peat moss

36 Aquaculture Systems Filtration – Corner Filter Filter Floss
Activated Carbon

37 Aquaculture Systems Filtration: Outside Power Filter AQUARIUM
Sponge, water conditioners or zeolite can also be added Filter floss AQUARIUM Activated carbon To electric

38 Aquaculture Systems Filtration – Undergravel Filter Air lift pump
Aeration through water movement Power Head

39 Aquaculture Systems Filtration – foam filter
Movement of water can be through the use of an air lift pump or a power head Foam filter has limited capability– hospital tank; fry tank

40 Aquaculture Systems Filtration – Canister Filters
such filters are usually on very large systems External Internal Activated Carbon Filter Floss

41 Aquaculture Systems Water Exchanges
Dilutes waste products, corrects pH Water Change pH Organics Ammonia Nitrite Nitrate TIME

42 Water Quality Management
Raceways: water flow = carrying capacity Ponds: pond depth and photosynthesis dissolved oxygen ability of pond to conduct nitrogen cycle to detoxify N-compounds Cages: total carrying capacity = that of the body of water had the cages not been present

43 Water Quality Management (cont.)
Recirculation Systems: Water must be managed/monitored carefully DO: provided mechanically Detoxification of N-compounds: performed by large biofilters Need to carefully monitor the performance of these life support systems


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