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Trapnetting and Spawning Broodstock for the Hackettstown Hatchery


The Hackettstown Hatchery's busy trapnetting season kicks off with the melting of ice on lakes and reservoirs in mid-March and runs through the end of April. The open water allows hatchery technicians to set trap nets for the collection of northern pike, muskellunge and walleye broodstock. The eggs from these fish are hatched in incubators and the fry raised to fingerling size (up to 10") for stocking in public waters.

Broodstock collected during the trap netting season are brought back to the hatchery where the spawning operations take place. Upon arrival the fish are separated by gender (male and female) and ripeness (degree of egg developement). Also during their short stay at the hatchery information such as length, weight and any fish markings, such as fin clips or tags, are recorded.

The fish will be returned to the their respective body of water after spawning operations are completed.

A trapnet is emptied
Fish are netted out of a trapnet
Click to enlarge

At the hatchery the fish will be anesthetized (put to sleep) by adding the drug tricaine to a tub of water and placing the fish in the tub. The fish are then manually stripped of their eggs and milt (fluid containing sperm) which are mixed into a bowl. This allows fertilization to occur. The fertilized eggs are then water-hardened, counted and measured into hatching jars. Eggs will hatch in 10-15 days.

For accounts of the past few years' broodstock collection see the links on the Hackettstown Hatchery page. For enlarged photos of the thumbnails below, click on the image.
Trapnet of muskellunge
Muskellunge in a trapnet
Anesthetized northern pike
Anesthetized northern pike
Stripping northern pike
Northern pike stripped as milt is added
Stripping female muskie
Female muskie being spawned
Muskie head is controlled during stripping
Female muskie's head is controlled
Walleye broodstock in tank
Walleye broodstock
Walleye scales are taken for aging
Walleye scales are taken for aging
Walleye is measured and weighed
Walleye is measured and weighed
Male and femail walleye are spawned
Walleye milt and eggs are stripped
Walleye being stripped of eggs
Walleye being stripped of eggs
Walleye milt and eggs are mixed
Walleye milt and eggs are mixed
Five million incubating walleye eggs
Five million incubating walleye eggs

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Copyright © State of New Jersey, 1996-2006
Department of Environmental Protection
P. O. Box 402
Trenton, NJ 08625-0402

Last Updated: June 23, 2006