U.S. Fish & Wildlife Service
 
 
     

A YEAR IN THE LIFE OF ATLANTIC SALMON

AT CRAIG BROOK NATIONAL FISH HATCHERY

 

Developing Salmon Eggs

 


Fall - Spawning Activities      
  Winter - Egg Development  
  Spring - Fry Stocking  
Summer - Broodstock Collection      
 
Spawning Demonstration
 Craig Brook National Fish Hatchery was established in 1889 to raise and stock juvenile Atlantic salmon for Maine waters. Craig Brook currently supports two Atlantic salmon programs.

As part of the restoration program for the Penobscot River, Craig Brook receives sea-run adult Atlantic salmon trapped from the Penobscot River for use as broodstock. These adults are spawned in the fall of every year and produce up to 3 million eggs. Approximately one million of these eggs are transferred to Green Lake National Fish Hatchery for Penobscot River smolt production. The rest of the eggs are raised at Craig Brook and released as fry.

Craig Brook supports the recovery of six Atlantic salmon populations within the Gulf of Maine Distinct Population Segment that were listed in 2000 as an endangered species. Juvenile Atlantic salmon are captured from the Dennys, East Machias, Machias, Narraguagus, Pleasant and Sheepscot rivers annually and brought to Craig Brook for captive rearing. These juveniles are reared at Craig Brook to sexual maturity and spawned to produce fry that are stocked back into the same river the parents were captured in.

An important component of both programs at Craig Brook is the genetic screening of broodstock. All broodstock, both Penobscot sea-run adults and DPS juveniles, are genetically characterized through DNA analysis to ensure that no undesirable genes are inadvertently introduced into the broodstock population.

Broodstock in Pool
Adult broodstock are separated by gender in pools prior to spawning.
Male Atlantic salmon
Male Atlantic salmon develop a kype, or hooked jaw, during the spawning season.
Broodstock
Broodstock are placed in a tub of water containing a fish anesthetic.
Male in Tub
This male has been placed in the anesthetic and is waiting to be spawned.
Scanning Female
All broodstock have small tags inserted under their skin. Before spawning the fish are scanned and the number is recorded.
Spawning Penobscot Girl
Compressed air is injected into the body cavity of females to facilitate the removal of the eggs.
Adding Sperm to Eggs
Milt, or sperm, is stripped from the males and added to the eggs.
Combining Eggs and Milt
As the milt is added, a paintbrush is used to combine the eggs and milt. This ensures that all the eggs are fertilized.
Eggs and Milt in Spawning Pan
Here, the eggs and milt are combined in a spawning pan.
Entering Spawning Data
All spawning data is entered via laptop computers into a database.
Straining Eggs
Once the eggs have been fertilized, they are rinsed with fresh water and strained.
Putting Eggs in Trays
The eggs from each female are placed into individual incubator trays.

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