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Last modified
7/14/2009 5:02:34 PM
Creation date
5/20/2009 10:39:09 AM
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Template:
UCREFRP
UCREFRP Catalog Number
9338
Author
Schler, P. J.
Title
Colorado Pikeminnow Culture Manual.
USFW Year
2001.
USFW - Doc Type
FY92-37,
Copyright Material
NO
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<br />8 <br /> <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br /> <br />container. Each window was covered with mosquito netting (30 squares/inch cloth screen). <br /> <br />Each hatching/rearing container had its own air supply via an airstone connected to an airline <br />from an aquarium pump (Whisper 800, Willinger Bros. Inc., Oakland, New Jersey). This air supply <br />was crucial to the survival of both eggs and fry when the window screens became plugged. It was <br />very important to clean the containers' window screens several times during the hatching process to <br />eliminate egg membranes from plugging water flow and fouling the water. <br /> <br />For this size tray, 4 ounces of eggs or less is recommended. Higher densities make it hard to <br />control fungus and smothering of eggs. Several of these egg tray/container combos were used if the <br />lot had more than four ounces of eggs. <br /> <br />The percent of individual lots that hatched varied greatly from year to year and from lot to <br />lot.. Several lots had 0%, while others were as high as 70%. After hatching, the egg trays were taken <br />out and the sac fry remained in the hatching/rearing container. <br /> <br />REARING CONTAINERS AND CAPACITIES <br /> <br />HATCHERY <br /> <br />Rearing Containers (Within Troughs) <br />The small hatching/rearing containers described in the Egg Trays and HatchinglRearing <br />Containers section provided an ideal container to closely observe the tiny fry. It reduced the labor <br />of cleaning the entire trough and provided a perfect environment to start training fry to feed. The <br />action of the airstone suspended food longer. A much better feeding response occurred when fish <br />were at higher densities within the containers. The increased density of fry appeared to facilitate the <br />buddy system for fry learning to feed. <br /> <br />Through trial and error, it was found shape and color of the hatching/rearing container was <br />very important to survival of newly hatched fry. The container needed to be round to help keep the <br />fry from bunching up in a comer and smothering. White seemed to be a color that helped disperse <br />fry throughout the entire container. <br /> <br />It was necessary to confine very small fry (1,455,000+/lb at swim-up) to these containers for <br />the first 60 days. With more space, they bunched up in the comers of stainless steel tanks and <br />smothered one another. When feeding starts, clean the containers' window screen several times a day <br />to improve water circulation and quality. <br /> <br />Rectangular Tanks <br />During culturing in 1989-90, the FRH modified existing cold water rearing troughs (six <br />fiberglass troughs 12ft x 1.6ft x 1ft and seven fiberglass troughs 20ft x 105ft x 1ft) for pikeminnow <br />culture. Due to the small size and delicate nature of sac fry and fry, the large troughs were difficult <br /> <br />. <br />
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