Methods used to propagate conservation aquatic species differ from those used to produce species commercially. Conservation propagation is population driven, labor intensive, and feed variety is important. Feed rates, tank design, tank size, and densities differ compared to commercial production. In Edenton, North Carolina, hatchery biologists have partnered with the Raleigh Ecological Services Office, North Carolina Wildlife Resources Commission, and North Carolina State University to propagate several conservation species.
Two fish species are being propagated as host fish for endangered freshwater mussels. Mussels release glochidia (offspring) in the water column to attach to a fish gill. Some freshwater mussels tend to be specific to their host species. Research has shown the Tar River Spinymussel (Elliptio steinstansana) to be partial to the White shiner (Luxilus albeolus) and the Dwarf Wedge mussel (Alasmidonta heterodon) to the Johnny darter (Etheostoma nigrum). In 2019, a total of 1,600 juvenile fish were produced for Tar River Spinymussel hatcheries and programs. In 2022 (pilot year), 350 juvenile Johnny darters were produced and will be distributed to Dwarf Wedge mussel programs in winter of 2023. Two endangered aquatic species are also being reared at Edenton. Carolina Gopher frogs (Rana capito) are listed as endangered by the state of North Carolina and currently being reviewed under the Federal Endangered Species Act. In North Carolina, Gopher frog populations have decreased from twenty-three to seven known populations. In 2021 (pilot year), 116 Gopher frogs were released in the Croatan National Forest. Cape Fear shiners (Notropis mekistocholas), an endemic fish species, are also being propagated at Edenton. These fish are localized to the Cape Fear River basin and some of its tributaries. In 2020 (pilot year), no juvenile fish were produced. In 2021, 5 juveniles and their parents were released in the confluence of the Deep and Rocky rivers. In 2022, 517 juveniles and their parents were released in the Cape Fear River.
Struggles and successes are present in the production of each species. Johnny darters are specific to what color structure they lay their eggs, and trials were conducted to determine when and how to remove eggs from broodfish tanks. White shiners prefer larger groups to spawn with and need nests to successfully spawn. Modified minnow traps were not as successful at capturing newly metamorphed frogs as anticipated. Cape Fear shiners have eggs and fry that are nearly invisible! The tough egg and fry visibility causes struggles with retrieving, enumerating, and cleaning. Every conservation species is reared differently, however, they have the same goal: produce quality organisms, keeping body composition, morphology, and physiology in mind. This process starts at rearing and ends with a successful release. As knowledge and experience with these species is gained, rearing and release methods continue to be optimized.