8010

• UCREFRP Catalog Number: 8010
• Author: Montagne, M.
• Title: The Grand Valley Propagation Facilities - 1997 Annual Report.
• USFW Year: 1998.
• USFW - Doc Type: Grand Junction, CO.
• Copyright Material: NO

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Table 9.

Lot and source of 1996-year-class razorback sucken stocked into the San
Juan River in fall of 1997

Lot 24 Road Clymers Pond Total
9601A 0 230 230
9603A 671 88 759
9610 642 0 642
Total 1313 318 1631

1997

On Apri123, 1997, razorback sucker eggs, spawned from broodstock held at Horsethief, were
transferred into the hatchery and acclimated. As before, the eggs were bathed in formalin every
day to avoid fungal growth. Hatching success varied from approximately 1 % to 20% (Table 10).
Of the 17 family lots spawned, only four lots hatched successfully. Poor hatching success may be
attributed to a sudden drop in temperature at Horsethief ponds just before spawning. The week
before spawning was to take place, water temperature reached 600 F and the: razorback broodstock
were ripening. The fish were injected with hormones and they were progressing normally to
spawning. However, the day before the fish were to spawn, the weather changed and both the air
and water temperature dropped. The air temperature dropped to near freezing and water
temperature dropped to 500F. The fish had to be spawned because they were ripe and ready to
go. The water temperature at the 24 Road Hatchery was approximately 750 F on the day of
spawning and there was no means to cool it down. Although the eggs were tempered before
being placed in the hatchery, the 250 difference in water temperature may have been to much for
the eggs to adapt to. This large temperature difference between spawning water and the rearing
water may have been responsible for the poor hatching success. Another factor in the poor
hatching success may have been poor water quality at the hatchery when the eggs were transferred
to the facility. The biofilter was not working properly at that time and ammonia and nitrite levels
were higher than normal. The high levels of these toxic compounds may have harmed the eggs and
led to poor hatching success.

The day before eggs were transferred to the facility, phenethyl alcohol was circulated throughout
the facility to imprint the fish for future chemoreception work. The phenethyl alcohol was
removed from the system by a combination of evaporation and dilution over a period of 7 to 10
days.

As of December 1, 1997,604 razorback suckers (representing four family lots) are being reared at
the 24 Rd. Hatchery. Most will be transferred to Horsethieffor future use as, broodstock. After
broodstock requirements are met, excess fish may be stocked into the Gunnison River in 1998.

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