Threats to Our Aquatic Ecosystems

Written by Jim Page and Rebecca Brown

Aquatic Nuisance Species.  When many folks in Georgia think of those terms, several species may immediately come to mind: flathead catfish, spotted bass, hydrilla, water hyacinth, snakeheads, or blueback herring, just to name a few.  While each of these are classic examples of aquatic nuisance species (ANS) that have been found in Georgia, there are other ANS that occur here that may not be at the tip of the tongue.  Two of these critters are animals that impact both our aquatic AND terrestrial ecosystems:  nutria and feral hogs.   

The Swamp Rat

It’s easy to think of fish when discussing ANS, but rarely do people think about the “swamp rat” that also bears the ANS title.  Native to South America, nutria is a large rodent similar to a cross between a beaver and a muskrat, having a long slender tail and webbed feet.  Introduced into the U.S. during the early 1900’s by fur traders, it was believed that the species would boost the fur industry and generate easy money.  Nutria were kept and raised in captivity in several locales throughout the U.S. as fur-traders banked on the species being the future of the fur industry.  However, the crash of the fur trade brought about the release of hundreds/thousands of nutria nationwide.  The subsequent consequences of such releases were felt soon after.  A voracious eater, these herbivores can consume 25% of their body weight each day (similar to grass carp) munching on the roots of wetland vegetation.  The consumption of these roots caused historical wetlands to transition into open water habitat.  Additionally, the species was found to tunnel along the banks of streams and rivers, causing damage and increasing soil erosion.  Thus, what started as a release with no intentional harm of a cute furry critter resulted in significant ecological impacts and the loss of precious wetlands around the country.  The impacts of nutria continue to this day, and the International Union for Conservation of Nature (IUCN) lists the nutria as one of the top 100 world’s worst invasive species.

Nutria

The Opportunistic Omnivore

Unfortunately, nutria were not the only furry critters to be introduced into the U.S. that have ended up being a nuisance in the aquatic world.  As early as the early 1500’s, early European settlers brought with them domestic pigs.  Unfortunately, some of these pigs escaped captivity and began life anew in the wild.  The additional introduction of wild boar into the U.S. by hunters in the 1900’s resulted in what we now have today:  a feral swine population which is a mix of wild boar, escaped domestic pigs, or a hybrid of the two. 

For many of us, the memories of Wilbur in “Charlotte’s Web” makes us question what can be so wrong with have these potbellied porkies running loose in our ecosystem.  Though they may seem innocent, feral swine, or wild pigs, have caused some of the most significant negative impacts to our ecosystems.  In fact, some scientists say wild pigs are the greatest vertebrate modifier of natural communities in the United States.  A walking vacuum, they will eat just about anything that can fit into their mouth.  In the process of searching for food, they root around in the soil, causing significant destruction to many of our native plant communities and agricultural crops.  The USDA estimates feral pigs cause around two billion dollars of damage each year!

The feeding habits of feral pigs have reduced plant and forest communities and caused an increase in soil erosion.   Adding to the damage is their love for wallowing in moist soil located in and near riparian zones and wetlands, destroying vegetation and loosening the soil in these sensitive areas.  Loosened soil is later washed into local streams and rivers, creating sedimentation and water clarity issues.  Additionally, the waste from pigs contains vectors for disease and nutrients which are added to waterways as part of surface runoff.  Too many nutrients can cause algal blooms or hypoxic zones, which can easily lead to a fish kill.   

The aquatic impacts of feral swine are not limited to freshwater ecosystems.  Since their arrival onto barrier islands along the Georgia coast hundreds of years ago, feral pigs have created significant problems in the marine ecosystem.  In addition to destroying plants on these island ecosystems, the feral pig has created significant harm to one of our most treasured coastal inhabitants – sea turtles.  Egg-bearing sea turtles utilize the beaches of barrier islands for nesting, digging shallow holes above the high-tide mark and depositing several dozen eggs before covering them up and returning to the ocean.  The keen nose of the feral swine has proven to be efficient in detecting the nest of these endangered and threatened turtles, and upon discovering a nest feral pigs will dig up the nest and destroy the eggs.  Such destruction can have detrimental impacts to the stability of sea turtle populations and to our continued efforts to protect them.  

Feral pigs in South Georgia

Our Choices

The introduction of ANS species like feral swine and nutria have taught us many lessons, perhaps none more important than the fact that releasing species in areas outside their native range can have devastating ecological and economic impacts.  Though the introduction of these 2 species was not done with ill intention, it should be a lesson to us that such actions, well intended or not, can create significant challenges and hardships for our native species and environments.  As humans, it is the responsibility of each of us to aid in the proper management of the ecosystems in which we live and call home.  We need protection of sea turtle nests if growth and sustainability of the species our goal.  We need protection of our sensitive wetlands and other terrestrial habitats susceptible to destruction by introduced species like nutria.  We need stable plant communities along riparian zones to reduce the amount of sediments that are washed into our waterways during rainfall, creating turbidity issues and reducing the amount of sunlight in the water needed by plants for photosynthesis.  Sediment pollution in aquatic ecosystems can clog fish gills, causing increased stress for and decreased ability of the fish to resist disease.  An excess of suspended sediments can decrease visibility for visual predators like trout and black bass species.  Eventually these suspended sediments begin to settle and blanket gravel beds with sediments, possibly covering fish eggs and other aquatic organisms.  This sedimentation process alters the geology and diversity of the aquatic ecosystem and degrades viable habitat for aquatic organisms.  Both the nutria and the feral pig contribute to these and other problems, and thus we need to learn from the choices of our past and not continue to repeat them.

Educate Others

Feral swine and nutria are now well-established and, though we wish we could turn back the hands of time, we cannot and thus must live with our choices.  However, the choices of tomorrow do not have to mirror the choices of our past.  It is important as fisheries professionals that we educate the public about the consequences of introducing non-native species into aquatic ecosystems.  It is imperative that we take the time to visit schools, speak to civic groups, utilize social media and other outreach platforms, and share with this generation and the next the importance of understanding the negative impacts our native species will endure should we choose to continue introducing ANS in our state and beyond.  How many of us have reached out to our own family members or friends and shared our knowledge and expertise?    Knowledge is power…spread the word…stop the ignorance!

Restoring Aquatic Connectivity

“The ecosystem is greater than the sum of its parts.” Eugene Odum

All around the world conservation groups, government agencies, academic institutions, and private companies are working together in efforts to restore aquatic connectivity and reduce habitat fragmentation by razing dams and restructuring road-stream crossings.  Georgia has its fair share of aquatic connectivity projects.  We have seen the removal of dams on the Chattahoochee River in Columbus and the removal of White Dam in Athens.  One project you may have not heard of is the Mill Creek/Rocky Flats Fish Passage Project in the Chattahoochee National Forest in Murray County. 

The Mill Creek Fish Passage Project was a joint effort between The Nature Conservancy, U.S. Forest Service, U.S. Fish and Wildlife Service, and Georgia DNR.  A damaged culvert was replaced with a bottomless arch culvert (pictured).  The streambed of this popular trout stream was restored to its natural condition.  Several threatened and endangered aquatic species like the Blue shiner and the Georgia Pigtoe will now be able to utilize the several miles of valuable habitat located upstream of the Rocky Flats trail.

Comparable to dams, culverts can fragment habitats and create barriers which restrict movement up and downstream for aquatic organisms.  This restriction can lead to increased competition for food, habitat, and mates; increases in predation; and an interruption of natural breeding and spawning cycles.  Furthermore, these barriers can affect genetic diversity when populations of fish are separated into localized groups.  The restoring of aquatic connectivity is necessary to allow aquatic ecosystems to interact and increase biodiversity.   The conservation of biodiversity is crucial in preserving ecosystem resiliency.

Read more about some of Georgia’s aquatic connectivity projects.

World Fish Migration Day is October 24, 2020 (Connecting fish, rivers, and people)

Georgia Aquatic Connectivity

Transforming a Fishery Using Proactive Fisheries Management Strategies

Written by David Beasley, Director of Fisheries at SOLitude Lake Management

The Cohoke Fishing Club is a 47-member private sports club formed in 1900 in Central Virginia. The property is home to an 85-acre mill pond that was built in 1678. Throughout the club’s existence, quality Largemouth Bass catch rates have been inconsistent. In 2009 the fishery was at a low point; the bass were poor in quality, the catch rates were down and the pond was overrun with hydrilla. The club opted to work with a professional fisheries management company to achieve their goal of improving the bass population.

An initial assessment that included electrofishing and habitat surveys was conducted to identify limiting factors and formulate an effective fisheries management strategy. Following this step, meetings were held with club members to review the collected data, gather opinions, and design a comprehensive management plan based on goals and budget:

Hydrilla Management

The first management step was to eradicate the invasive hydrilla present throughout the waterbody. Based on the budget and site conditions, the best long-term, budget-friendly control method available was to stock Triploid Grass Carp. This was done in the spring of 2010 in combination with a 10-acre herbicide treatment at the upper end of the pond to ensure anglers had access to the entire waterbody. With these combined approaches, the hydrilla was reduced by 100 percent within the first growing season.

Fish Stocking

Because members had elected to manage the fishery on a relatively low budget, it was important for the club to focus on improving the predator- to-prey ratio and fish habitat. Initial electrofishing results indicated that Gizzard Shad comprised the majority of the forage base. On the other hand, Bluegill and other sunfish were low in population due to decades of anglers harvesting all Bluegill and releasing all bass. This past approach played a role in the shad’s dominant position. To help rebuild the population while working with a small budget, 6,000 adult Bluegill were stocked and creel limits were altered to release all Bluegill while harvesting intermediate size Largemouth Bass.

Fish Cover and Nuisance Wildlife Removal

Club members added habitat strategically throughout open water to create cover for bass to ambush the shad. The fish cover installed also helped all species avoid predation from otters and cormorants during the cooler months, in particular, when water clarity improves and fish slow down due to cold water temperatures. In response to the large number of otters observed in the pond, an annual trapping program was implemented to reduce their population. Both of these strategies underscored the club’s goal of creating a self-sustaining, abundant forage base capable of supporting trophy bass.

Productivity

Improving the fishery’s productivity was an important step in the process of boosting the forage fish population. In 2010, extensive water quality data was collected to better understand the limiting factors. The waterbody was then put on a fertilization program as well as a water quality monitoring program to help ensure success. In addition to fertilizing, multiple fish feeders were installed to boost Bluegill growth rates and rebuild their depleted population. 

Member Education

The final step in the process was education; if fishermen do not follow through with the management tasks required, then the fishery will not meet its potential. As is the case with many fishing clubs, the members had to overcome internal struggles in order to achieve the desired results. Members were instructed to no longer catch and release intermediate size bass. It is often very difficult to get anglers on board with doing the opposite of what their parents and grandparents had taught them, even when frustrated with the existing fishing conditions. The inherited resistance to harvesting bass was the primary hurdle preventing the pond from producing more consistent, high quality fishing.

2015 marked five years since the management strategy was set in motion. Over that time, the management tasks were carried out annually. Although all of the club members would not consistently conform to harvest recommendations, they did make strides in the right direction. Creel limits for Largemouth Bass were followed, but revised. Even though the club members failed to harvest the recommended number of bass within the first couple of years, over time they were able to get the member buy-in and make a significant impact. In the process of harvesting Largemouth Bass, efforts were also made to remove all other predators present in the pond, including black crappie, chain pickerel and white perch – and this proved to be a very effective strategy.

In line with the concern of some anglers, catch rates gradually decreased by around 20 percent over the years, but the quality of the bass increased significantly. The fishery transformed from anglers catching only one 15-inch bass for every five bass caught, to greater than 50 percent of the bass caught being greater than 15in. The 20 percent lower catch rate in exchange for a very positive shift in the quality and size of the fish has garnered enough support from the club’s members to start harvesting all bass less than 15in beginning in 2016. 

The extensive historical fishing data from this pond illustrates that it has the potential to become great. In order for the club to continue with its success, it will need to stay focused on each of the following variables that impact bass growth: predator-to-prey ratios, water quality, plankton production, fish cover, otters, record keeping and harvesting. 

David Beasley is the Director of Fisheries at SOLitude Lake Management, the nation’s leading environmental firm specializing is sustainable lake, stormwater pond, wetland and fisheries management solutions. To learn more about this topic, please visit www.solitudelakemanagement.com.

Becoming a Hutton Scholar Mentor Webinar

Calling all interested and past Hutton Mentors! Are you interested in applying to be a Hutton Mentor but not sure the responsibilities of hosting a high school student for the summer? Have you been a Hutton Mentor and looking to learn from other past Hutton Mentors about the opportunities they set up for their Hutton Scholar? Tune in for a panel of three past Hutton Mentors to learn about and share best practices for student internships. Join us Friday, May 1st from 12-1pm EDT for the webinar: Becoming a Hutton Scholar Mentor – Inspiring, Rewarding, and Surprisingly Easy! Register by following this link: https://attendee.gotowebinar.com/register/8262334408948075533

AFS Webinar: CREATING A MOVEMENT TO SAVE MIGRATORY FISH FROM LOCAL TO GLOBAL

This webinar has been rescheduled for April 30, 2020

Ongoing river fragmentation and dam construction are two of the greatest global threats to freshwater biodiversity and ecosystem functioning. Hence, migratory fish around the world are severely threatened. Dams are blocking these fish while they need to migrate to reproduce, feed and complete their life cycles. They make up a crucial link in the food chain and play an important ecological role in productive river systems. Furthermore, they provide an important food supply and livelihood for millions of people around the world. These migratory routes are called swimways. Some species like Atlantic Eel and the Goliath Catfish (Amazon River) have swimways of around 11.000km. For the existence of these fish it’s crucial that these swimways are open and provide habitat to breed and reproduce.

The World Fish Migration Foundation was founded in 2014 to save migratory fish in rivers, from local to global. WFMF brings global attention to the problems and the solutions and provide tools to river practitioners to preserve and to open swimways. In 2014 the foundation initiated the first World Fish Migration Day (WFMD) with a partnership of 6 organizations (WWF, The Nature Conservancy, eg). WFMD is bi-annual event which starts in New Zealand and follows the sun around the world, ending on Hawaii. The central message “Connecting fish, rivers and people” is used to connect sites around the world. The last edition in April 2018 hosted 570 local events organized by over 3000 organizations. The WFMD created a growing movement around migratory fish. It helps to reach students, teachers, resource managers, commercial and recreational anglers, as well as those who influence public policies. After 3 editions the global reach is 50-70 million people through (social) media. The fourth edition is planned for May 16, 2020.

Recent reports from Europe and the USA conclude that the removal of dams is a very effective ecological restoration measure as rivers recover faster than expected after dam removal. Furthermore, it is becoming increasingly clear that dam removal is often a cost-effective measure. For these reasons the World Fish Migration Foundation and six partners started the Dam Removal Europe Movement in 2016. The ambition is to make dam removal a viable option for river management and to restore fish populations. After 4 years the development of this movement is a success and now we want the scale this up through channelizing funding and reach out to a bigger audience by starting crowd funding campaigns for dam removals. The ultimate ambition is to use the experiences from the USA and Europe and create a global dam removal movement.

Presenter’s Biosketch

Herman Wanningen is founder and creative director of the World Fish Migration Foundation (WFMF). With a strong background in water management and aquatic ecology, he has developed a successful career in fish passage over the past 20 years. He is leading the efforts on developing fish migration visions and policies at a global scale. Herman facilitates and activates communication between the worldwide fish migration expert community, key-decision makers and policy makers. He gives advice on national and international fish passage and river connectivity projects such as the Fish Migration River project (The Netherlands), Dam Removal Europe and AMBER Horizon2020 project. This last project aims to map all barriers in European rivers and to provide management tools.

Herman is known on the international stage for developing the World Fish Migration Day (2014, 2016 and 2018), organizing international conferences and developing fish migration networks. In 2018 over 3000 local and regional organizations organized 570 events in 63 countries. Herman is coordinator and co-author of three international From Sea to Source books on fish migration. He has won an award for his management of the successful Fish Passage conference in 2015 in Groningen. He is manager of the World Fish Migration Day 2020 and recently became Fellow under the Mulago Fund Program.

For information about registration: https://fisheries.org/2020/03/webinar-march-24-creating-a-movement-to-save-migratory-fish-from-local-to-global/

 

 

AFS Webinar: Mythbusting Marine Aquaculture

Mythbusting Marine Aquaculture

Thursday, February 27, 2020
1:00 pm Eastern Time

Presenters:
Jennifer Molloy, U.S. Environmental Protection Agency, Siting and Water Quality
Mike Rust, Ph.D., NOAA Fisheries
Guillaume Salze, Ph.D., Ajinomoto Animal Nutrition North America, Inc.
Jesse Trushenski, Ph.D., Riverence
Craig Watson, University of Florida

Register Now!

Description:
Marine finfish aquaculture in the United States represents an opportunity to provide domestic seafood, create jobs, contribute to coastal economies, and help improve community health. Significant advances in fish farming technology and best management practices have decreased the environmental footprint and increased the economic performance and sustainability of marine aquaculture.

Hear from experts about how proper siting and husbandry, best management practices, and the use of appropriate technologies and tools are minimizing or eliminating diseases, therapeutants, excess nutrients in benthic habitats, and the release of nonnative species.

AFS Webinar on January 28

AFS Book Preview: Multispecies and Watershed Approaches to Freshwater Fish Conservation Tuesday, January 28, 2020 1:00 pm Eastern Time Presenters: Daniel Dauwalter Trout Unlimited Timothy Birdsong Texas Parks and Recreation Department Gary Garrett University of Texas at Austin Registration Link: https://attendee.gotowebinar.com/register/8364194263774714893

Description:
Freshwater systems in the United States have been altered dramatically, resulting in degradation of fish habitats and declines in native freshwater fishes. Innovative conservation approaches are needed to restore watershed processes for freshwater fish conservation while simultaneously supporting human needs. This need has driven development of innovative multispecies and watershed-based concepts, assessments, prioritizations, planning, and delivery that focus conservation efforts on entire aquatic communities at watershed scales while incorporating species life history needs and acknowledging compatible human uses. These approaches have yielded multi-agency partnerships and large-scale funding programs focused on operationalizing conservation plans and supporting meaningful and transformative conservation delivery for freshwater fishes and their habitats. This book, which was borne out of a symposium titled “Multispecies and Watershed Approaches to Native Fish Conservation:  Science, Planning, and Implementation” held at the 2017 American Fisheries Society Annual Meeting in Tampa, Florida, highlights these innovative approaches to freshwater fish conservation, profiling case studies from freshwater systems throughout the United States that include diverse partnerships encompassing state, federal and local agencies, watershed councils, non-governmental organizations, and Fish Habitat Partnerships. The book also profiles highly effective and successful conservation programs and initiatives that have spanned entire careers and represent decades of unwavering commitment and passion by agencies, organizations, and individuals to restore and preserve freshwater systems. Some of these individuals have left a lasting conservation legacy through their incredibly productive and impactful careers and have offered figurative road maps to guide and inform the efforts of current and future conservation professionals. The case studies highlighted in this book simply show it is possible to successfully effect change at watersheds scales for multiple species and set a high bar for the next generation of aquatic conservationists and fisheries managers focused on the conservation of freshwater fishes.  https://fisheries.org/2020/01/webinar-on-january-28/