Seth Morgan & Erik WithalmOregon Department of Fish and Wildlife

Ultraviolet Disinfection At Leaburg Hatchery

ZAPPED!!!!

BackgroundLeaburg’s historical trout stocking program

Produce 240,000 lbs of rainbow trout400,000 eggs were historically hatched onsite

First IHN outbreak in rainbow trout in 1995Generally follows a major stressor such as transport, grading, fin clipping, or diseaseSource of IHNV is summer steelhead migrating over Leaburg dam, above our water supply

Leaburg Hatchery Hatch-houseMcKenzie River source waterHeavy silt loads during rain and flood eventsInternal fungus and coldwater disease in fry

High mortalityStressor which can make fry more susceptible to IHN

13 shallow Canadian troughs640 gallons each

2 deep Canadian troughs960 gallons each

Limited well water supply

Ultraviolet Disinfection SystemIntegrated drum filter with 8 UV lampsRated for 500 gpmFilters water to 25 micronsUV dose of 45,000 µw-sec/cm²254 nm wavelength

UV System Assembly & Installation

Seth Morgan

Jennifer Hulett-Guard

Tim C. Wright

Ken DanisonDan Murphy

Supply Pump

Outflow pumps

Overhead plumbing

Microprocessor UV Control Station

Silt-laden Incoming Water

Clean, Filtered Outgoing Water

Ultraviolet Lamp Chamber

Tony AmandiManny Farinas

Design Considerations Supply Water Overflow

If the filter can’t keep up with the incoming water due to heavy silt loads, the water goes directly through the lamps, bypassing the filter. Therefore, the water won’t be properly disinfected.

Design Considerations (cont.)Drum Filter LidDuring back wash operations mist containing untreated water could contaminate treated water at the end of UV unit and surrounding fish culture containers.

Rubber flap

Mist

Price of Clean Water

Cost for base UV system: $42,000$4200 for four 250 gpm pumpsTotal cost of installed system: $50,000Operating cost $10 per day

Hatch-house MortalityRainbow Trout

0102030405060708090

100

2004 2005 2006 2007 2008

% Mortality

Mortality numbers are expressed as a percent of total rainbow trout inventory in the hatch house.

Bacteria Counts

0

100

200

300

400

500

600

700

800

Jun-08 Jul-08 Aug-08 Sep-08

Bacteria Colonies - TYE

Pre Filter TYEPost Filter TYE

050

100150200250300350400

Jun-08 Jul-08 Aug-08 Sep-08

Bacteria Colonies - TSA

Pre Filter TSA

Post Filter TSA

Post filter

Pre filter

Estimated Maximum Capacity

0

20,000

40,000

60,000

80,000

100,000

120,000

140,000

160,000

180,000

25 50 75 100 125

Fish size (Fish/lb.)

Num

ber o

f Fis

h

170,000 fish @ 100 fish/lb.

127,500 fish @ 75 fish/lb.

85,000 fish @ 50 fish/lb.

42,500 fish @ 25 fish/lb.

Assumes a maximum carrying capacity of 100 pounds of fish per shallow trough, which means an instantaneous value of 1,700 pounds of fish total in the hatch-house.

What We’ve AchievedStill limited to stocking “YES” waterbodiesKeep fish in the hatch-house on clean water longer

Shorter exposure time on McKenzie River waterFish are larger with a more developed immune system before ponding outside in river waterDecreased prevalence of internal fungus and coldwater disease during the fry stage, common stressors that can make the fish more susceptible to IHNV.

Looking Forward

Whole hatchery UV disinfection system would be optimal. We’ve shown how important a clean or disinfected water supply is to raising healthy fish.