Populations of paddlefish in the United States have been on the decline over the past few decades primarily because they are one of three egg-bearing species that are permitted to be commercially fished and exported for their eggs. With a decline in Caspian Sea sturgeon stocks, which was the main source of caviar, canneries have been using other species of fish, including paddlefish, to create caviar.
To mitigate these declines, Pvt. John Allen National Fish Hatchery is culturing paddlefish for restoration across the Southeast. The hatchery has contributed to restoration efforts in Tennessee, Louisiana and is currently working with the Mississippi Department of Wildlife Fisheries and Parks to re-establish paddlefish populations in the Tennessee Tombigbee Waterway and the Pascagoula River Basin with fish supplied by Pvt. John Allen NFH.
Paddlefish broodstock are collected using gill nets early in the spring, usually in March, when water temperatures are beginning to rise to 60 degrees fahrenheit. The broodstock are collected from the Bouie River, which is within the Pascagoula River Basin. The paddlefish are transported back to the hatchery where they are spawned.
Stripping paddlefish eggs
Hatchery staff remove eggs from female using a modified minimally invasive surgical technique. The sperm is collected from the males using a catheter and a syringe. Both the male and female paddlefish are returned to the wild after spawning is complete.
Fertilization is completed by mixing the sperm with the eggs and then adding a small amount of water to activate the sperm. Fertilization occurs within seconds of adding the water. Fuller’s Earth is added to the fertilized eggs to make sure the eggs do not stick to one another. After 15 minutes of stirring, the Fuller’s Earth is rinsed from the eggs and the eggs are placed into our hatching system.
Hatching fry from eggs
After seven days the paddlefish fry begin to hatch. The fry are not fully developed when they hatch. During this time are are absorbing nutrients from a yolk sac. The fry are shipped to multiple hatcheries before they need to feed from their mouth. After a few days the paddlefish are fed plankton, brine shrimp and then transitioned to an artificial diet. The remain at the hatchery for three months until they are large enough to be released in the wild. They typically reach eight inches. The larger the paddlefish are, the greater the chance they will survive in the wild.
The paddlefish are released in the Leaf River, which is in the Pascagoula River system, to augment the existing population. Every paddlefish receives a coded wire tag to differentiate hatchery reared paddlefish from wild reared paddlefish.