Spinymussel returns to James River
A small invertebrate that scientifically goes by the name James River Spineymussel has not been seen alive in the waterway its named for since the late 1960s.
“We’re pretty confident that they’re extirpated from the main stem river and even if they’re still out there, they’re probably at such low levels that they’re not really biologically like they should,” said Brian Watson, a top biologist for freshwater mussels at the Virginia Department of Wildlife Resources.
On Wednesday morning, Watson and his crews were at five locations on the James River to reintroduce about 1,300 individuals back into the waterway. These were all raised at a mussel hatchery in Charles City.
The goal is to repopulate a species that is one of dozens of freshwater mussels that used to be commonplace in what is now North Carolina, Virginia, and West Virginia.
For many years, biologists in Virginia have taken this seriously.
“We have about 80 species which ranks us about sixth in the United States in terms of diversity,” Watson said.
Watson said there are roughly 900 species of freshwater mussels across the globe and around 300 are in the United States. One of those species is the James River Spineymussel, which is on the federal endangered species list as critically endangered.
Watson said the small creatures play an important role in the ecosystem as they feed from their position on the beds of rivers and lakes filtering water for food and nutrients.
“We often talk about freshwater mussels as the livers of the river,” Watson said. “When you’re heard historically about how oysters could clear the Chesapeake Bay, the entire water volume, within about a month when oysters were at their heyday, freshwater mussels used to do a similar thing for our freshwater creeks and streams and rivers.”
For decades, aquatic biologists have sought to restore creatures back to habitats that became uninhabitable due to all sorts of pollution. An interesting adjective to describe mussels is “benthic” which means anything that lives on the bed of a waterbody.
“And since these are benthic organisms that live in the stream bottoms and they don’t move around like freshwater fishes do, they are relatively good indicators of water quality so if something is going wrong at a site or there’s a change for the negative for water quality, mussels are usually going to give you an indication that something’s going on.”
To get mussels to be in a place takes a lot of factors, so Watson said putting them back in a former habitat from which they’ve disappeared means a lot of biological steps will need to be taken.
“They kind of have a unique life cycle for an invertebrate,” Watson said. “They are an obligate parasite, most of them are. They have a larva that typically has to attach to a particular fish species to complete their life cycle. So it’s a really small larvae that females hold inside of their gills.”
Watson said a small shell that looks like a Pac-Man will snap shut when in the presence of the fish to hitch a ride. They’ll use chub, minnow, or several other species.
“And if they’re successful and stay on the fish, they will transform into a juvenile, drop off, and if they happen to drop off in a suitable location and conditions are right then they will grow to be a sub-adult and then an adult.”
If the fish have moved on, then the life cycle is interrupted. Some species of mussels can live for decades, but they may die out if the waters are impaired.
For decades, biologists have been restoring fish to rivers made more habitable by the Clean Water Act. Now research into doing the same thing for invertebrates, including this release of the James River Spineymussel. To make that work, the Virginia Department of Wildlife Resources has approached the local governments in Albemarle, Buckingham, and Fluvanna counties to ask for permission even if might not strictly have been necessary.
“The way the language reads in our current regulation is that if we’re going to introduce any new species to an area that is a game animal or a game bird or a fish that we need the authority and the cooperation of the local government of the locality it will be released into,” Watson said. “So when you look at that language it doesn’t necessarily say freshwater mussel or invertebrates.”
Watson said notifications have been made because of the regulated nature of the James River Spineymussel. In Albemarle, its presence in the 1980’s was enough to put regulatory approval of the Buck Mountain Reservoir in doubt and the project was abandoned.
In 2022, Albemarle’s consent for the release was on the consent agenda for their May 18 meeting. Watson had an audience with the Buckingham County Supervisors earlier this month but had not heard back from Fluvanna as of this past Tuesday when our interview was conducted.
The project definitely has the support of Matt Lawless, the administrator of the Town of Scottsville.
“Having a healthy and scenic river that’s accessible and safe for everybody to use is what Scottsville is all about,” Lawless said. “That’s been our history for hundreds of years and we feel really responsible for our little piece of the river and we take its quality and its health very seriously.”
The individual mussels released are all three years old and Watson said they should be ready to reproduce.
“Right now we would consider them adult mussels,” Watson said. “They should be reproductively mature so that when they are released into the river, assuming that every goes right, that they should start reproducing next year or within the first years that they’re out in the river so that they’re not young individuals that are just dropping off of the fish.”
The work to propagate mussels dates back to the late 90’s and Watson said teams used to send them out at an earlier stage in the life cycle. The results were not successful. This batch has been kept in the hatchery longer than usual due to various approval processes.
So, how will Watson and his team measure success? There are three metrics. First, they’ll check to see how many survive.
“The second is are they reproducing after you put them out,” Watson said. “So at the certain time of the year when the females would have those larvae inside of them, we will try to monitor those locations and check some of those animals to see if they are what we call ‘gravid’ or not and that’s when the females have the larvae inside their gills.”
The third step is to see if those larvae can get onto the fish as part of their role as obligate parasite. All of the individuals that went out this week are tagged so they can be monitored.
“So the hope will be that as we monitor these in the future, if we start to see younger individuals that do not have tags on them, then that tells us that they are new individuals that are recruiting into the population.”
Watson said it is inevitable that many of the introduced species will float downstream over time and that they won’t be detectable. Still, he predicts survival rates will be high. Monitoring efforts will continue and Watson said people should be patient for results.
“And it could take a decade or two to actually see something going on,” Watson said. “There have been some restoration and recovery work with rare mussels out in the Mississippi River where they put lots and lots of individuals out there. You’re talking like thousands to tens of thousands of animals out in spots and they are just now starting to see recruitment in some of these areas where they’ve placed large numbers and you’re like a decade later.”
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