Aquatic Wildlife Conservation Center
Located near Marion, Virginia, the Aquatic Wildlife Conservation Center (AWCC) was established in 1998 by the Virginia Department of Game and Inland Fisheries to actively recover Virginia's freshwater mussels. Over the past ten years, 2,618,500 juvenile mussels of 24 species have been propagated, with over 638,000 being released back into the wild.
The AWCC has also begun work with other aquatic wildlife, including the state-threatened spiny riversnail (Io fluvialis) and the eastern hellbender (Cryptobranchus alleganiensis alleganiensis — learn more). Between 2005 and 2008, 10,960 juvenile spiny riversnails from the Clinch and Powell rivers have been released. In addition, 32 juvenile eastern hellbenders have been raised from eggs.
Mussel Production Systems at AWCC
Recirculating systems are used at AWCC to propagate freshwater mussels. These systems feature tanks with individual inflow and outflow. Host fish infected with larval mussels are kept in tanks. Out-flowing water is filtered to collect juveniles after they fall off the host fish and then is filtered and pumped back through the system. Two kinds of systems are used: one for larger fish (e.g. largemouth bass or rock bass) and one for smaller fish (e.g. darters or sculpin). These systems are designed to allow propagation of more than one species per system at a time.
Juvenile Rearing
Juvenile mussels are counted and measured when they drop off the host fish. They are then placed in a rearing system to allow them to grow large enough to increase their chances of survival in the wild. The rearing systems include an array of 5-liter tanks that are supplied with filtered water from the river. The water is filtered to eliminate predators that might consume small juveniles. Another rearing system has recently been added using re-circulated water, allowing staff to control the system's water temperature and food content. Each tank is also fitted with a filter to catch any juveniles that might escape between sampling events.
The AWCC is constantly developing and testing new systems and methods of rearing juvenile mussels in an effort to reach optimum growth and survival rates.
Featured Species: Mountain creekshell (Villosa vanuxemensis)
The mountain creekshell is a small freshwater mussel, with adults measuring between 40-65 mm (1.5-2.5 inches). The exterior of the shell, called the periostracum, can range from olive, to light brown or black. Younger animals may have fine rays marking their shell, but the lines are less visible as the animal reaches adulthood. This species is sexually dimorphic, meaning males and females can be differentiated by looking at their shell. Females have a prominent swelling on the lower posterior margin, and a point near the top of the posterior margin creating a triangular shape. Male shells are usually more oval shaped and lack the swelling the females need to accommodate brooding gills full of larvae. The interior of the animal's shell, called the nacre, is usually purple but can also be coppery in color.
The mountain creekshell is a long-term brooder, also called bradytictic, meaning animals spawn in the late summer to early fall. Gravid females hold their larvae over winter (September - July). In the wild its host fish species include sculpin, a small bottom-dwelling fish, and rock bass.
The mountain creekshell can be found in parts of Virginia, Tennessee, Kentucky, North Carolina and Georgia, primarily in tributaries of the Tennessee River (Clinch, Powell, and Holston Rivers in Virginia). Animals are often found along river banks in slow moving water with substrate high in organic matter, but can also be found in sandy substrates in riffles. This species is also found in small headwater creeks.
At the Aquatic Wildlife Conservation Center, the mountain creekshell is propagated using sculpin. In 2009, over 8,100 juveniles were produced. Currently, over 1,900 are being held at AWCC to be tagged and released this year in the Clinch River. Although is not listed as endangered, the mountain creekshell is typically uncommon where it occurs. Our efforts will boost wild numbers to ensure that this species persists well into the future.
