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Hackettstown State Fish Hatchery - 2017 Broodstock Collection and Spawning


by Craig Lemon
Hatchery Superintendent
June 13, 2017

The production season for the Hackettstown State Fish Hatchery kicks off each year with broodstock collection for Northern Pike in Budd Lake. Northern Pike spawn within a narrow time frame following ice-out. Ever changing weather patterns, and especially unseasonable warm trends, can make it very difficult to pinpoint the start of the spawning season. Over the Bureau of Freshwater Fisheries' 37 years of broodstock collection, the season on Budd Lake has started as early as March 3 (1998) and as late as April 6 (2015) depending on the severity of winter and timing of ice out.

This year New Jersey experienced the warmest February on record since data collection began 122 years ago. With high temperatures throughout February in the 50s, 60s and even the 70s, hatchery staff had to make the call on when to set trapnets in Budd Lake. Would the pike be ripe yet? Did they spawn early? Hearing forecasters predicting winter was returning by the end of the week with colder, snowy weather, hatchery staff pulled the trigger and set 3 South Dakota-style trapnets in Budd Lake on Tuesday March 7. The forecast was accurate and staff braved the wind and snow on Friday, March 10, pulling nets. In the following four days 135 adult pike had been captured. A good number compared to 99 in 2016 and only 8 in 2015.

Giant muskie returned to Greenwood Lake
Giant muskies were among this year's catch
Click to enlarge
Northern Pike
Staff contended with snow on Budd Lake
Worker with large northern pike
Click images to enlarge
The pike catch consisted of 71 males and 64 females. The 64 females was the highest number captured since 2000 when 85 were captured. Of the 64 females, 26 were spawned at the hatchery producing 648,490 eggs for an average of 24,942 eggs per female.

The nets captured a total of 1,808 fish representing 16 different species. Black Crappie, White and Yellow Perch, and variety of sunfish made up the majority of the catch.

Staff only bring the pike back to the hatchery for spawning; all other fish are released on the spot. Lake temperatures ranged between 39 - 43 degrees. Crazy thing is a fellow Fish and Wildlife friend of mine spent his birthday just two weeks later ice fishing Budd Lake. Of additional interest is the fact that as I am putting these thoughts together on June 1, hatchery staff are halfway through float stocking the 25,000 plus six-inch Northern Pike fingerlings.

Egg take - 3/8 - 3/12
Egg hatch - 3/18 - 3/22
Stocking six-inch fingerlings - 5/26 - 6/10 (69 days after hatch)

Mother Nature turned mid-March into a winter wonderland, producing 4 inches of snow on March 10 and then unleashing a blizzard with over a foot of snow on March 13 and 14. Days of plowing and shoveling transitioned to hatching Northern Pike eggs after ten days of incubation. Once again, staff faced the waiting game for snow and ice to melt and for Swartswood Lake to refill after a winter drawdown.

Workers spawning northern pike
Click image to enlarge

Walleye trapnetting at Swartswood over the past 17 years has kicked off as early as March 15 (2016) and as late as April 6 (2015). So much for the lake filling, or should we say flooding. Staff set nets near the mouth of Neldon Brook on March 27, and were greeted with runoff from snow melt and five inches of rain that fell over the next ten days making trap netting very challenging. Despite flood conditions, which results in nets full of debris, hatchery staff persevered and eight days of netting resulted in catches of 8, 4, 5, 70, 11, 2, 66, and 53 fish.

In total, 219 Walleyes were captured, 56 more than 2016. The Walleye catch was made up of 118 males and 101 females. The females made up 46% of the Walleye catch, the highest percentage in 10 years. Staff attribute this high percentage to the fact that many of the males may have run up the brook prior to the nets being set. A total of 816 fish were captured, representing 16 species with Bluegills and Yellow Perch making up the bulk of the catch. Lake water temperatures ranged from 39 - 46 degrees while netting. Of the 101 female Walleye captured, 69 came in ripe, 27 unripe, and 5 spent. A total of 74 females were spawned at the hatchery producing 7.4 million eggs an average of 100,368 eggs per female.

Egg take - 3/31 - 4/4
Egg hatch - 4/14 - 4/19
Stocking 1.5-inch fingerlings - 6/6 (53 days post hatch)
Stocking 4-inch fingerlings - 8/1 (120 days post hatch)


Phase three of the trapnetting season is the search for "the fish of 10,000 casts", the purebred Muskellunge. Netting dates over our 21 years have ranged from an early start of March 27 (1999) to as late as April 19 (2007). This year kicked off April 10, when the crew set two Pennsylvania Style trap nets in Greenwood Lake, one near the mouth of Belcher's Creek and a second across the lake in a spot known as the "State Land Set".

Checking nets at Echo Lake Reservoir
Checking nets at Echo Lake Reservoir
Click to enlarge
The nets captured an impressive 27 muskies, 9 males and 18 females. The nets were checked five different times from April 10 to April 17 capturing 14, 4, 3, 5, and 1 on the last day. That final fish, on the last day, brings to mind a quote some of you may remember from the original "Jaws" movie, when Captain Quint said, "Back home we got a taxidermy man. He gonna have a heart attack when he see what I bring him." That fish turned out to be the biggest fish the hatchery has handled in its 23 years of trap netting. The unripe female weighed a whopping 38.12 pounds measuring 49.2 inches. Prior to this giant, the biggest Muskie handled was a Greenwood Lake female captured April 8, 2008 that weighed 36 pounds and measured 48.5 inches.

This year's Greenwood nets yielded 2,387 fish including 80 Walleye, and large numbers of Yellow and White Perch, Alewives, Black Crappies, and a variety of sunfish. Water temperatures ranged between 54 and 62 degrees. Of the 18 females captured, 2 came in ripe, 15 unripe, and 1 spent. A total of 11 females were spawned in the hatchery yielding 773,311 eggs, an average of 70,301 per female.

The same day hatchery staff pulled the nets out of Greenwood Lake, they made their way south to the Newark Watershed's Echo Lake Reservoir and set two Pennsylvania and one South Dakota style trapnets in search of a handful of ripe Leech Lake strain Muskies. The three nets were fished from April 17 - April 21 capturing 11 muskies, 4 males and 7 females. The nets were checked twice, with 6 muskies on April 19 and 5 more on the 21st. Four were ripe females and were spawned with Echo Lake males producing a nice jar of 125,000 eggs. The nets captured a total of 546 fish representing 10 other non-target species such as Bluegill, Black Crappie and Yellow Perch, Largemouth and Smallmouth Bass. Water temperatures ranged from 51-56 degrees. Muskie females typically ripen when water temperatures reach 50 degrees.

Between the two lakes, a total of 19 female muskies were spawned producing about 1.25 million eggs. The last of the eggs hatched May 9 and the fry were recently float stocked in Echo Lake Reservoir. This year's Muskellunge eggs hatched at a rate of 51%, slightly above the 23-year average of 47%, producing 650,000 fry. Once hatched the fry spend the next 7 to 10 days basically lying on the bottom of the tank feeding off their yolk sacs (sac fry). Once the yolk sac is absorbed they are able to swim off the tank bottom and become free swimming (swim-up fry). At this point hatchery staff do weight counts and inventories setting up 100,000 swim-up fry in ten 350-gallon round tanks at 10,000 per tank.

The next 15 days are tough when hatchery staff begin to convert the fry onto dry pelleted diets. This conversion consists of cooking and hatching small batches of brine shrimp eggs and feeding the shrimp five times per day to the muskie fry. Muskellunge, unlike other Esocid Family members which include Northern Pike and Tiger Muskellunge (hybrid), insist on eating a moving food source as opposed to the dry feed just slowly dropping straight down through the water column. The tiny fry are fed 15 days of live brine shrimp, each day mixing in more dry feed, slowly weaning the fry off of the shrimp at the end of the two-week period.

As the fry are growing the feed particle size is increased every couple of days, and the fish begin to go for the larger pellets as soon as it is introduced. By this time hopefully a good percentage (50%+) will have taken to the dry food diet. Feeding brine shrimp and continually hand feeding helps reduce cannibalism, which can be their biggest obstacle.

Daily cleaning of these round culture tanks with these tiny fry is a tedious process and takes extreme care. The muskie fry are raised both indoors in hatchery tanks and outdoors in earthen ponds. The target number for many years has been 12,000 ten-inch fingerlings by November 1st. Following the recent multi-year Coolwater Assesment by Bureau biologists, hatchery staff have been asked to produce and distribute 6,000 fall 10-inch fingerlings and 4,300 12-inch spring yearlings. They will be stocked in 11 waters with each getting yearlings on alternating years.

Egg take - 4/13 - 4/24
Egg hatch - 4/28 - 5/9
Stocking 10-inch fingerlings - 10/15 (170 days post hatch)
Stocking 17-inch yearlings - 8/1 (450 days post hatch)

Hackettstown Superintendent and article author Craig Lemon with 38 lb muskie
Hackettstown Superintendent Craig Lemon hoists 38 lb. muskie
Click to enlarge
All adult muskies handled at the hatchery over the past 20 years have been tagged with orange streamer tags inserted near the base of the dorsal fin. To date over 600 Muskellunge have been tagged. This year, 9 of the 38 (24%) Muskellunge trapnetted were previously tagged. The crew captured the enourmous female muskie noted above on the last day in Greenwood Lake carrying tag number 343. The unripe fish weighed a whopping 38.12 pounds measuring 49.2 inches. She was previously tagged by hatchery staff on April 4, 2010. At that time, she weighed 28 pounds and measured 45 inches. Hatchery staff estimated her age to be about 15 years old. The tags bear the message "CALL HACKETTSTOWN HATCHERY (908) 852-4950" along with a tag number. Anglers, who call in to report catching a tagged fish will be told when the fish was tagged, and its length and weight at the time of tagging. Reports of tagged fish provide the hatchery and state fisheries biologists with important growth information on the state's Muskellunge fisheries.

Fish For the Future

In coordination with fisheries biologists from the Bureau of Freshwater Fisheries, the Hackettstown Hatchery is raising the following numbers of Northern Pike, Muskellunge, and Walleyes to meet the state's needs for 2017:

25,500 six-inch Northern Pike fingerlings for stocking in:
Pompton Lake and Pompton River (Passaic); Spruce Run Reservoir (Hunterdon); Budd Lake (Morris); Farrington Lake (Middlesex); Millstone River (Somerset) and the Passaic River (Morris).
Cranberry Lake (Sussex) surplus only

6,000 ten-inch Fall Muskellunge fingerlings/4,300 twelve-inch Spring yearlings for stocking in: Greenwood Lake, Monksville Reservoir and Echo Lake Reservoir (Passaic); Lake Hopatcong (Morris/Sussex); Mercer Lake (Mercer); Mountain Lake and Furnace Lake (Warren); Little Swartswood Lake (Sussex); and DOD Lake (Salem).
Manasquan Reservoir (Monmouth) surplus only
Carnegie Lake (Mercer) surplus only
Cooper River Lake (Camden) surplus only

100,000 two-inch & 35,000 four-inch Walleye fingerlings for stocking in: Lake Hopatcong (Morris/Sussex), Swartswood Lake (Sussex), Greenwood Lake (Passaic), Canistear Reservoir (Sussex), Monksville Reservoir (Passaic).
Surplus Walleye will be stocked in the Delaware River (Sussex/ Warren counties).

Below are summary tables of fish collected in spring, 2017.

BUDD LAKE 3 135 25.6 19.1 - 34.4 3.99 1.06 - 11.6
Males   71 23.5 19.1 - 31.2 2.83 1.06 - 6.08
Females   64 27.8 21 - 34.4 5.19 2.12 - 11.6

GREENWOOD LAKE 7 27 39.9 33 - 49.2 18 8.6 - 38.12
Males   9 37 33 - 40.5 13.4 8.6 - 17.54
Females   18 41.3 34.5 - 49.2 20.2 10.52 - 38.12
ECHO LAKE RESERVOIR 4 11 43 38 - 48 18.6 12.52 - 28.18
Males   4 40.7 38 - 42.9 15.7 12.52 - 17.7
Females   7 44.3 39 - 48 20.2 14.12 - 28.18

SWARTSWOOD LAKE 7 219 20.2 12 - 27.4 3.6 0.7 - 9.58
Males   118 19 12 - 23.5 2.85 0.7 - 5.3
Females   101 21.6 17.6 - 27.4 4.47 2 - 9.58

While reading through this information you might think, "Wow they take a lot of eggs and hatch a lot of fry where do most of them go?" Unlike species such as Rainbow Trout and Channel Catfish that typically hatch at rates in the 90% range, these species hatch rates can vary from 0 to 70%, with values in the 50% range considered good. We set up the number of fry that we are comfortable with that will meet our final stocking needs. After that, surplus fry may be stocked in other water bodies or offered to other States in trade. In 2017, surplus hatchery fry from the Hackettstown State Fish Hatchery helped out fisheries programs in five other states including Pennsylvania, New York, Massachusetts, Connecticut, and Virginia. We have been trading surplus Northern Pike fingerlings for Landlocked Salmon yearlings with Massachusetts for a number of years and an exciting Salmon fishery is developing in three North Jersey waters.

The Hackettstown State Fish Hatchery also raises 12 other species of fish for waters throughout the state - see the production and stocking summaries for details. All fish raised at the Hackettstown Hatchery are stocked in public waters throughout the state to provide recreational fishing for licensed anglers and their families. The hatchery also raises several species of fish to assist the state's mosquito control efforts. The hatchery stocks 2-3 million fish annually. The Hackettstown Hatchery is supported entirely through the sale of fishing licenses and Federal Sport Fish Restoration grant monies generated from the sale of fishing equipment.

Sport Fish Restoration Program Logo The Hackettstown Hatchery is supported entirely through the sale of fishing licenses and federal Sport Fish Restoration Program grant monies generated from the sale of fishing equipment.


arrow Hackettstown Hatchery Broodstock Collection Reports
arrow Hackettstown Hatchery Stocking Summaries
arrow Swartswood Broodstock Data Collection
arrow Warmwater Fishing Has Never Been Better!
arrow Freshwater Fishing in New Jersey
arrow Warmwater Fish in New Jersey

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Last Updated: June 13, 2017