Restoring and Revitalizing Freshwater Mussels

Freshwater mussels are among the oldest living and second most diverse organisms on Earth with over 1,000 recognized species. Here in the eastern part of the U.S., we have more species of freshwater mussels than anywhere in the world. Unfortunately, freshwater mussels are one of the most rapidly declining animal groups in North America. Out of the 300 species and subspecies found on the continent, 70 (23%) have been federally listed as “Threatened” or “Endangered” under the Endangered Species Act. And, in the last century, over 30 species have become permanently extinct. So, why are populations declining so fast?

Freshwater mussels are filter feeders and process large volumes of the water they live in to obtain food. This means of survival also makes them highly susceptible to industrial and agricultural water pollution.  Because they are constantly filtering water, the contaminants and pathogens that are present are absorbed into the mussel’s tissues. As such, mussels are good indicators of water quality and can greatly contribute to improving water quality by filtering algae, bacteria and organic matter from the water column.

Not only do freshwater mussels rely on water quality, they are dependent on fish and other aquatic organisms for reproductive success. In order for a freshwater mussel to complete the reproduction process, it must “infect” a host fish with its larvae. The method depends on the specie of mussel. Some species lure fish using highly modified and evolved appendages that mimic prey. When a fish goes into investigate the lures, the female mussel releases fertilized eggs that attach to the fish, becoming temporarily parasitic. Once the host fish is infected, it can transfer the mussel larvae upstream and into new areas of the river.

Both habitat loss from dam construction and the introduction of pesticides into the water supply has contributed to the decline of freshwater mussels. With approximately 300 mussel species in the U.S. alone, a critical component of restoring and revitalizing mussel populations is truly understanding their biology, which begins with the ability to properly differentiate each species and properly identify and catalog them. Princeton Hydro’s Senior Scientist Evan Kwityn, CLP and Aquatic Ecologist Jesse Smith recently completed the U.S. Fish and Wildlife Service‘s Fresh Water Mussel Identification Training at the National Conservation Training Center in West Virginia.

Through hands-on laboratory training, Evan and Jesse developed their freshwater mussel identification skills and their knowledge of freshwater mussel species biology. Course participants were tasked with mastering approximately 100 of the most common freshwater mussel species in the United States. They also learned about proper freshwater mussel collection labeling, the internal and external anatomy and meristics of a freshwater mussel, and distributional maps as an aid to freshwater mussel identification.

In a recently published press release, Tierra Curry, a senior scientist with the Center for Biological Diversity was quoted as saying, “The health of freshwater mussels directly reflects river health, so protecting the places where these mussels live will help all of us who rely on clean water. This is especially important now, when we see growing threats to clean water from climate change, agriculture and other sources.”

Princeton Hydro is committed to protecting water quality, restoring habitats, and managing natural resources. Read about some of our recent projects and contact us to discuss how we can help you.

To learn more about freshwater mussels, check out this video from U.S. Fish and Wildlife Service:

“2018 Land Ethics Award of Merit” awarded to Mullica River Wetland Mitigation Project

At the 18th Annual Land Ethics Symposium, which is presented by Bowman’s Hill Wildflower Preserve, Princeton Hydro and GreenVest, LLC were honored with the “2018 Land Ethics Award of Merit” for our restoration work at the Mullica River Wetland Mitigation Site.

We teamed up to restore the natural wetland hydrology on a 34-acre parcel of land which was heavily impaired and intensely manipulated for cranberry production over the last century. The area was home to a network of earthen berms surrounding cranberry cultivating bogs, where water onsite was managed through a series of ditches and water control structures set into the berms. The cranberry operation was bordered mostly by an Atlantic white cedar dominated swamp.

“Thank you to Bowman’s Hill for honoring this successful wetland restoration project,” said Mark Gallagher, Vice President of Princeton Hydro. “Through our partnership with GreenVest, we transformed a degraded cranberry bog into thriving emergent and forested wetlands, and restored historic headwater stream channels. These restored wetlands are providing invaluable habitat to a variety of threatened and endangered species in New Jersey, including the Pine Barrens Treefrog and Barred Owl.” 

 

While this site was degraded, it still contained four state listed species, including the state-endangered Timber Rattlesnake and the Pine Barrens Tree Frog, making it a priority site for restoration. The presence of these species influenced the design as it included provisions to incorporate habitat elements for these species.

Through the implementation of restoration activities focused on removing the site’s agricultural infrastructure, Princeton Hydro and GreenVest were able to restore a natural wetland system on the site. In addition, the restoration project reconnected the site to its floodplain and re-established a natural stream channel. The expansive, flat and wide floodplain wetland complex of the Alquatka Branch of the Mullica RIver provides floodplain connectivity for relatively frequent storm events and allows for a sustainable floodplain wetland complex in the former cranberry bog cells.

The completed project incorporated a balance of both ecological and human health and safety benefits. Additionally, the project involved innovative restoration techniques that required building consensus among local watershed protection groups and state and regional regulators, including New Jersey Department of Environmental Protection and the New Jersey Pinelands Commission. In the end, the project restored 34 acres of a highly functioning forested wetland/upland complex and reestablished 1,600+ linear feet of historic headwater stream channels.

Princeton Hydro would like to thank Bowman’s Hill Wildflower Preserve for both the award and for a organizing another successful Land Ethics Symposium. The conference focused on ways to create low-maintenance, economical and ecologically balanced landscapes using native plants and restoration techniques. Princeton Hydro was a proud “Friends Sponsor” of the event.

 

Conservation Spotlight: FORTESCUE SALT MARSH AND AVALON TIDAL MARSH RESTORATION

HABITAT RESTORATION THROUGH APPLICATION OF DREDGED MATERIAL

New Jersey, like other coastal states, has been losing coastal wetland habitats to a combination of subsidence, erosion and sea level rise. The New Jersey Department of Environmental Protection received a grant from the National Fish and Wildlife Federation to address this issue and rejuvenate these critical habitats. Grantees were charged with providing increased resilience to natural infrastructure that will in turn increase the resiliency of coastal communities in the face of future storms like Hurricane Sandy.

As a consultant for GreenTrust Alliance, a land conservancy holding company, Princeton Hydro worked with several project partners, including NJDEP, the US Army Corps of Engineers, NJDOT, The Wetlands Institute, and The Nature Conservancy, to increase the marsh elevation to an optimal range where vegetation, and the wildlife that depends on it, can flourish. One of the techniques used for this project included the use of dredged material disposal placement, which involves using recycled sand and salt dredged from navigation channels to boost the elevation of the degraded marsh.

A media statement from NJDEP further explained the process, “sediments dredged from navigation channels and other areas are pumped onto eroding wetlands to raise their elevations enough to allow native marsh grasses to flourish or to create nesting habitats needed by some rare wildlife species. Healthy marshes with thick mats of native grasses can cushion the impact of storm surges, thereby reducing property damage.”

FORTESCUE SALT MARSH

The salt marsh at the Fortescue project site is part of the Fortescue Wildlife Management Area. The specific goal of the project was to restore and enhance the interior high and low marsh, coastal dune and beach habitats.

To achieve these habitat enhancements, the Princeton Hydro project team first established biological benchmarks of each targeted habitat type and evaluated them to determine the upper and lower elevational tolerances for target communities and plant species. Approximately 33,300 cubic yards of dredged materials were used to restore a degraded salt marsh, restore an eroded dune, and replenish Fortescue Beach. The eroded dune was replaced with a dune designed to meet target flood elevations and protect the marsh behind it against future damage. The dune was constructed using dredged sand, and, to prevent sediment from entering the waterways, a Filtrexx containment material was used.

AVALON TIDAL MARSH

This project site is a tidal marsh complex located within a back-bay estuary proximal to Stone Harbor and Avalon. Princeton Hydro and project partners aimed to enhance the marsh in order to achieve the primary goal of restoring the natural function of the tidal marsh complex.

Two main activities were conducted in order to apply the dredged material to the impaired marsh plain: 1.) the placement of a thin layer of material over targeted areas of existing salt marsh to increase marsh elevations, 2.) the concentrated placement of material to fill expanding pools by elevating the substrate to the same elevation as the adjacent marsh. In total, dredged material was distributed among eight distinct placement areas throughout the property’s 51.2 acres.

These coastal wetland restoration activities will help to prevent the subsidence-based marsh loss by filling isolated pockets of open water and increasing marsh platform elevation. In addition, the beneficial reuse of dredged material facilitates routine and post-storm dredging and improves the navigability of waterways throughout the U.S.

AQUATIC ORGANISM PASSAGE: A PRINCETON HYDRO BLOG SERIES

Welcome to the second installment of Princeton Hydro’s multi-part blog series about aquatic organism passage.

What you’ll learn:

  • How does promoting aquatic organism passage benefit ecosystems as a whole?
  • How can others, including people, benefit from aquatic organism passage?
  • How has Princeton Hydro supported it?

Photo by Princeton Hydro Founder Steve Souza

Fostering Ecological Balance in Food Webs

A major consequence of poorly designed culverts published in the NRCS' "Federal Stream Corridor Restoration Handbook"is the destabilization of food webs. Sufficient predators and prey must exist to maintain a balanced food web. For example, freshwater mussels (Unionidae) are a common snack among fish. A mussel’s life cycle involves using certain fish as a host for their larvae until these microscopic juveniles mature into their adult forms and drop off. During this period, the host fish will travel, effectively transporting a future food source with it.

In the presence of habitat fragmentation, the isolation of these symbiotic relationships can be devastating. Some mussel species rely on a small circle of fish species as their hosts, and conversely, some fish species rely on specific mussel species as their food. If a fish species is separated from its mussel partner, food shortages owing to a declining adult mussel population can occur.

Widespread Benefits to Flora, Fauna, and People

A shift in the 1980s recognized the importance of redesigning road-stream crossings for several reasons, including restoring aquatic organism passage and maintaining flood resiliency. Replacing culverts with larger structures that better facilitate the movement of both water and aquatic organisms benefit all species. Roads constructed over streams allow people to travel across natural landscapes while culverts that are fish-friendly convey water at a rate similar to the surrounding landscape, reducing scour in stream beds.

A man fly fishes as his dog sits by his side at Ken Lockwood Gorge, Hunterdon County. Photo from State of New Jersey website.

Fish, as well as semi-terrestrial organisms like crabs and salamanders, can take advantage of more natural stream environments and complete their migrations. Anglers appreciate healthy, plentiful fish populations nearly as much as the fish themselves. Recreation and economic growth also improve when streams regain the aquatic biological communities once lost through habitat fragmentation. According to USFWS, for every dollar spent on restoration through the Partners for Fish and Wildlife Program and Coastal Program Restoration Project, states gain $1.90 of economic activity. Stream restoration improves fish and wildlife habitat, which directly supports and enhances recreation opportunities for outdoor enthusiasts thus resulting in increased tourism-related spending and job growth.

Aquatic Organism Passage in Action at Princeton Hydro

Princeton Hydro recently completed a project to facilitate aquatic organism passage for river herring in Red Brook in Plymouth, Massachusetts. Read all about it here!

For an introduction to aquatic organism passage, be sure to check out the first post in this multipart-series.

Sources:

“Aquatic Organism Passage through Bridges and Culverts.” Flow. Vermont Department of Environmental Conservation’s Watershed Management Division, 31 Jan. 2014. Web. 14 Mar. 2017.

Hoffman, R.L., Dunham, J.B., and Hansen, B.P., eds., 2012, Aquatic organism passage at road-stream crossings— Synthesis and guidelines for effectiveness monitoring: U.S. Geological Survey Open-File Report 2012-1090, 64 p.

Jackson, S., 2003. “Design and Construction of Aquatic Organism Passage at Road-Stream Crossings: Ecological Considerations in the Design of River and Stream Crossings.” 20-29 International Conference of Ecology and Transportation, Lake Placid, New York.

Kilgore, Roger T., Bergendahl, Bart S., and Hotchkiss, Rollin H. Publication No. FHWAHIF-11-008 HEC-26. Culvert Design for Aquatic Organism Passage Hydraulic Engineering Circular Number 26. October 2010.

Michigan Natural Features Inventory. Freshwater Mussels of Michigan. Michigan State University, 2005.

 

Aquatic Organism Passage: A Princeton Hydro Blog Series

Introducing part one of a multi-part blog series about aquatic organism passage
What you’ll learn:
  • What is aquatic organism passage?
  • Why is it important?
  • How does Princeton Hydro support it?

This photo from NYS DEC demonstrates a well-designed stream crossing.

Since the US government began allotting funds for building roads in U.S. national forests in the late 1920s, hundreds of thousands of culverts were built across the country. Culverts, or drainage structures that convey water underneath a barrier such as a road or railroad, were originally built with the intention of moving water quickly and efficiently. While this goal was met, many migratory fish and other aquatic organisms could not overcome the culverts’ high-velocity flows, sending them away from their migratory destinations. If the culvert was perched, or elevated above the water surface, it would require the migratory aquatic animals to both leap upwards and fight the unnaturally fast stream current to continue their journeys. Additionally, turbulence, low flows, and debris challenged the movement of aquatic organisms.

Thus, the goal of aquatic organism passage (AOP) is to maintain connectivity by allowing aquatic organisms to migrate upstream or downstream under roads. AOP “has a profound influence on the movement, distribution and abundance of populations of aquatic species in rivers and streams”. These aforementioned species include “fish, aquatic reptiles and amphibians, and the insects that live in the stream bed and are the food source for fish”.

This photo from NYS DEC demonstrates a poorly-designed stream crossing.

A poorly designed culvert can harm fish populations in multiple ways. If sturgeon aren’t able to surpass it, habitat fragmentation prevails. And so, a once-connected habitat for thousands of sturgeon breaks into isolated areas where a few hundred now live. When the population was in the thousands, a disease that wiped out 80% of the population would still leave a viable number of individuals left to survive and mate; a population of a few hundred will be severely hurt by such an event. In sum, habitat fragmentation raises the risk of local extinction (extirpation) as well as extinction in general.

The splintering of a large population into several smaller ones can also leave species more vulnerable to invasive species. Generally, the greater the biodiversity harbored in a population, the stronger its response will be against a disturbance. A dwindling community of a few hundred herring will likely succumb to an invasive who preys on it while a larger, more robust community of a few thousand herring has a greater chance of containing some individuals who can outcompete the invasive.

Aquatic Organism Passage in Action at Princeton Hydro

Princeton Hydro recently teamed up with Trout Unlimited to reconnect streams within a prized central-Pennsylvanian trout fishery.  Our team enabled aquatic organism passage by replacing two culverts in Pennsylvania’s Cross Fork Creek. Read about it here!

Sources:

“Aquatic Organism Passage through Bridges and Culverts.” Flow. Vermont Department of Environmental Conservation’s Watershed Management Division, 31 Jan. 2014. Web. 14 Mar. 2017.

Hoffman, R.L., Dunham, J.B., and Hansen, B.P., eds., 2012, Aquatic organism passage at road-stream crossings— Synthesis and guidelines for effectiveness monitoring: US Geological Survey Open-File Report 2012-1090, 64p.

Jackson, S., 2003. “Design and Construction of Aquatic Organism Passage at Road-Stream Crossings: Ecological Considerations in the Design of River and Stream Crossings.” 20-29 International Conference of Ecology and Transportation, Lake Placid, New York.

Kilgore, Roger T., Bergendahl, Bart S., and Hotchkiss, Rollin H. Publication No. FHWAHIF-11-008 HEC-26. Culvert Design for Aquatic Organism Passage Hydraulic Engineering Circular Number 26. October 2010.