march, 1968 - Pennsylvania Fish and Boat Commission
march, 1968 - Pennsylvania Fish and Boat Commission
march, 1968 - Pennsylvania Fish and Boat Commission
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y SHYRL HOOD<br />
WALLEYE PRODUCTION- Assistant <strong>Fish</strong>eries Chief,<br />
Warmwater Production<br />
BUSY SEASON!<br />
SPRINGTIME IS A BUSY TIME for <strong>Pennsylvania</strong> <strong>Fish</strong><br />
<strong>Commission</strong> hatcheries throughout the state <strong>and</strong> the Linesville<br />
Hatchery in Northwestern <strong>Pennsylvania</strong>'s Crawford<br />
County is no exception.<br />
This headquarters for warmwater species production becomes<br />
a hub of activity as the ice goes off <strong>and</strong> the time<br />
arrives for collecting walleye eggs for another year's production.<br />
Due to the prohibitive cost <strong>and</strong> impracticality of maintaining<br />
walleye brood stock, the <strong>Pennsylvania</strong> <strong>Fish</strong> <strong>Commission</strong><br />
takes its brood stock from a wild population in the<br />
2,500-acre Pymatuning Waterfowl Sanctuary, an area not<br />
open to sport fishing.<br />
Nets are set as soon as the ice goes off, usually between<br />
March 20 <strong>and</strong> April 5 to capture the needed brood fish.<br />
Nets are set on gravel <strong>and</strong> s<strong>and</strong> bars, preferably in water<br />
5 to 7 feet deep, with the opening facing shoreward <strong>and</strong><br />
the lead extending to shore when possible.<br />
As catches are made records of each daily production<br />
are kept. Initially catches contain a high percentage of<br />
males with relatively few ripe females. Then, as the water<br />
temperature rises, the proportion of females increases until<br />
EMPTYING A TRAP NET—the crib of the net is taken aboard<br />
the bow of the barge, the fish transferred into the tank <strong>and</strong> then<br />
taken immediately to the hatchery.<br />
a peak in the number of ripe females is reached. This peak<br />
period of ripe females coincides with a water temperature<br />
in the mid-40's <strong>and</strong> usually lasts a week or ten days. In the<br />
meantime males become less abundant.<br />
Nets are checked daily <strong>and</strong> all adult walleye are transported<br />
in tanks to the hatchery building where they are<br />
separated into males, ripe females, <strong>and</strong> green females with<br />
each category being placed in separate tanks.<br />
Green females are checked daily <strong>and</strong> usually ripen<br />
within three days. In the meantime ripe females are<br />
spawned as soon as sorting is completed <strong>and</strong> before they<br />
can loose a large number of eggs.<br />
A large female may produce as many as 400,000 eggs,<br />
however the number varies with the size of the fish. Usually<br />
25,000 to 40,000 eggs are produced for each pound<br />
of fish.<br />
Preparing for the artificial spawning, hatchery personnel<br />
place males <strong>and</strong> ripe females into separate tanks containing<br />
an anesthetic of methyl pentynol. Once completely<br />
anesthetized—about two minutes at the concentrations used<br />
—they are rinsed in clean water <strong>and</strong> spawning begins.<br />
Three men usually help during the process. One expresses<br />
the eggs into a wet basin <strong>and</strong> simultaneously the<br />
sperm from two males is added to insure fertilization.<br />
After spawning, a small amount of water is poured into<br />
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