The Hudson River Eel Project: A community science framework for management and education

ABSTRACT

Community science, or citizen science, engages trained volunteers with professional researchers to answer a range of environmental ­questions. When buttressed with strong protocols and robust training, community science can be particularly useful in studying migratory fish by expanding the spatial and temporal scale of research. The Hudson River Eel Project is a community science program in which volunteers collect data on juvenile American Eel Anguilla rostrata numbers as the fish enter estuarine tributaries from the ocean. The Eel Project has been designed to (1) assist fishery agency managers in collecting robust data on young-of-year glass eel ingress, and (2) engage diverse audiences in relevant field science that leads to greater ecological stewardship and education. In this article, we describe the initial findings of 14 years of eel monitoring at six sites along the Hudson River estuary, explore how community science efforts can be applied to the needs of fishery agencies, and demonstrate the impact of community science in career development through short testimonials.

INTRODUCTION

Research and monitoring are often limited due to staff capacity, funding constraints, and wide geographies to cover. These limitations can lead to suboptimal sampling frequency, inconsistent data records, inadequate spatial reach, and a reduction in the overall robustness of data sets. Community science involving trained volunteers provides a unique opportunity to address these limitations and drive meaningful data collection. In addition, these efforts also provide an opportunity for diverse community members, most of them non-professional scientists, to learn about their home waterways and become informed advocates for fish and their ecosystems. The Hudson River Eel Project described here is one example of how local volunteers contribute to stock assessment, and how in return those volunteers benefit from the greater engagement community science provides.

Community science, also known as “citizen science,” involves the active participation of the public in organized conservation or research projects, often in collaboration with ­professional scientists (Dickinson & Bonney, 2012). Volunteer coordination dramatically increases research support capacity without significantly stressing budget constraints. This increased capacity allows for a higher frequency of data collection through time but also increases the spatial scope of the research. Programs like Litterati (https://www.litterati.org/) and iNaturalist (https://www.inaturalist.org/) tap environmental and ecologically invested community members to expand their data network nationally and globally. Public participation offers an educational opportunity while helping to effectively communicate academic findings to the broader public (Cigliano et al., 2015).

A note on terminology: In this study, we use the term community science instead of citizen science. We acknowledge that those terms are not viewed as interchangeable by all, and that language evolves. Our deliberate usage is because the term “citizen” has the connotation of legal U.S. citizenship status, which can exclude some members of our participant base. For these purposes, we define community as people in an area who have a shared interest, in this case, eel monitoring in a local waterway.

Community science can mobilize large groups of volunteers throughout an extensive study area, but critics have questioned the scientific value of community science efforts. Observation errors and biases can potentially result when survey work transitions from trained experts to volunteers (Dickinson et al., 2010). However, these errors can be avoided through oversight, training, and robust methodologies to ­ensure ­high-quality data collection (Brown & Williams, 2018; Clare et al., 2019; Kosmala et al., 2016). With careful development, a successful monitoring program can be built through the utilization of community science. In the Hudson Valley in the state of New York, this has been achieved through a coordinated network of volunteers that seeks to shine more light on one of the most mysterious fish in the Hudson River: the American Eel Anguilla rostrata.

The American Eel is one of 19 globally distributed species and subspecies of eels that form the family Anguillidae and are typically found in marine, coastal, and freshwater habitats (Righton et al., 2020). American Eels are catadromous, likely hatching in the Sargasso Sea before heading to coastal regions and often ascending freshwater tributaries, returning years later to the Atlantic Ocean to spawn only once upon maturity. The entire range of American Eels includes fresh waters of rivers, streams, and lakes, as well as the estuaries and coastal areas of the East and Gulf Coasts of North America and the Caribbean region (Miller et al., 2015; Tesch, 1977). Their unique life cycle between river and sea is fascinating and cryptic and is one reason why many people are interested in and inspired by Anguillid eels (Prosek, 2010). Even though people have been harvesting and studying eels for thousands of years, there are still unknowns about their life history. The life stage focused on in this study is the “glass eel,” when nearly transparent juvenile eels migrate into inland waters from the ocean.

Eels are an ecologically, commercially, and culturally important species. Their role as both predator and prey in ecological communities makes them a useful species for assessing ecosystem health (Itakura et al., 2020; Näslund et al., 2022). They are one of the most economically important fish species globally, and there is a valuable market for them throughout all their life stages (Kaifu et al., 2019). Because of their long history as a natural resource, eels have become enmeshed in cultural and social aspects of societies (Gansworth & Bowser, 2024; Tsukamoto & Kuroki, 2014). The heightened significance of eels means threats to their population are even more pressing.

The Atlantic States Marine Fisheries Commission (ASMFC) cooperatively manages American Eels from Florida to Maine (Rootes-Murdy & Anstead, 2019) and according to the 2023 American Eel Benchmark Stock Assessment, the population of American Eel remains depleted in U.S. waters and the stock is at or near historically low levels due to a combination of stressors (ASMFC, 2023; Jacoby et al., 2015). Stressors include dams and barriers to stream connectivity, habitat alteration, water quality, pollution, water ­temperature effects from climate change, and historic overfishing (Castonguay et al., 1994; Drounieau et al., 2018; Haro et al., 2000; Kruger & Oliveria, 1999). While the American Eel population has faced historic declines in the past decades, the U.S. Fish and Wildlife Service determined their depleted population is now stabilized, hence their lack of protections under the Endangered Species Act (Kahn, 2019; U.S. Office of the Federal Register, 2015).

American Eel and other anguillid eel species are considered “data poor.” Much of the historical data used to assess the population are based on fisheries-dependent survey data and commercial landings, the latter of which may be underreported, or influenced by market fluctuations and not on actual population trends (ASMFC, 2023). For a consistent fisheries-independent data set, the ASMFC developed a protocol for monitoring the young-of-year glass eel life stage as a measure of recruitment (ASMFC, 2000). Most states from Florida to Maine have adopted one or two sites to collect regular counts of glass eel ingress for 8–10 weeks each late winter into early spring. New York’s primary long-term site, operated by state biologists, has been on the south shore of Long Island, with a period of Hudson-based research done 2001–2005 (Schmidt et al., 2006). Wide dispersal in the ocean, followed by spreading throughout watersheds, makes this glass eel stage accessible for monitoring as they seasonally funnel through coastal estuaries each spring. Using recruitment as a measure of spawning success and as an overall stock assessment tool is a standard in fisheries management (Maunder & Thorson, 2019) and glass eel recruitment is an important tool for assessing biomass and stock status (Aranburu et al., 2014; ASMFC, 2023). Given the scarcity of data sets available for some stock assessments, survey data from well-run community science initiatives can be crucial to assist fisheries managers in better evaluating the status of the species (Stuart et al., 2024).

The New York State Department of Environmental Conservation (NYSDEC) launched the Hudson River Eel Project in 2008 to increase glass eel data available for management purposes. This collaborative project has both an agency-led component in terms of protocols and data management, but also a community-driven effort of volunteer recruitment and place-based specifics (Phillips et al., 2019). It is a community science project aimed at augmenting New York’s ­contribution to ASMFC stock assessments by empowering volunteers to conduct daily monitoring at established sites. The Hudson River Eel Project follows the ASMFC’s young-of-year sampling protocols (ASMFC, 2000) and previous Hudson glass eel monitoring (Schmidt et al., 2006), with trained volunteers performing the sampling (Figure 1). Significantly, the Hudson River Eel Project data set was included as a robust data set contribution to the most recent ASMFC American Eel Benchmark Stock Assessment report (ASMFC, 2023). This is a positive example of community-collected data directly supporting agency-level management and conservation efforts of a critical species.

In this paper, we examine the role of community science in the collection of eel monitoring data for the Hudson River Eel Project that has been accepted into coastwide management studies. We present glass eel counts at six long-term (minimum of 10 years) data collection sites along a 246-km tidal estuary, and compile an index of glass eel ingress across the Hudson sites. We introduce a framework of key factors that make community science ideal for eel monitoring and conversely, why anguillid eels are an ideal taxa for promoting scientific integration in local communities. Our discussion features testimonials from former Eel Project volunteers, highlighting the impact of the project on an individual level. These successes can be applied to future community science projects that contribute valuable information to the scientific and management community, on eels or many other topics.

METHODS

Preparation and placement

The Hudson River Eel Project collects data on glass eel ingress along a 246-km (153-mi) stretch of the Hudson River Estuary, from Staten Island to nearly the head of tide north of Albany, New York. Six primary sites have operated consistently for a full season since 2010: Minisceongo Creek, Furnace Brook, Fall Kill, Black Creek, Saw Kill, and Hannacroix Creek. Additional sites have run for less time or shorter seasons, but still provide valuable local context and educational opportunities throughout the Hudson Valley (Figure 2). The beginning of sampling each season is determined by tracking lower Hudson water temperatures from continuous water monitoring stations in lower Manhattan (HRECOS, 2024). Two lower Hudson partners employ artificial habitat collectors (Sullivan et al., 2006) when in-river temperatures reach 4°C. Once a glass eel has been reported in a habitat collector, fyke nets are installed by Eel Project coordinators from south to north from February through March. Each site typically runs for 6–10 weeks or until glass eel catches are near zero.

Community participants vary from site to site based on local organizations, but glass eel collection methods remain the same. Volunteer recruitment is done through a range of programs and presentations to high schools and colleges, and at public events. Most sites have one or more organizational partners to help train and organize volunteers under NYSDEC protocols. Participants receive training from agency staff or long-term partners, and first-year volunteers are teamed up with experienced veterans. Sampling schedules are shared with samplers online, and project leaders visit sites frequently.

Each net is located at the tidal mouth of a tributary to the Hudson River Estuary but does not span an entire stream width. The opening faces downstream to catch eels migrating from the mainstem estuary upstream into the tributary. Fyke nets are installed with one wing at the shoreline’s high tide line, and the net location is consistent each season with adjustments as stream morphology changes over time. Fyke net dimensions follow Schmidt et al. (2006).

Volunteer actions

Once installed in tributary mouths, nets are checked and any eels present are counted once per day. In a typical session at the eel net, volunteers suit up in waders and assemble the gear needed, typically stored on site. Multiple duties including net checking, eel counting, data recording, and gear maintenance, allow volunteers of different interests and strengths to work together collaboratively.

Daily data includes counts of young-of-year “glass eels” and slightly older and pigmented “elvers” (up to 15 cm), soak time between counts, and basic environmental parameters including water temperature, tide cycle, and any organisms other than eels. For our study, glass eels are defined as young-of-year eels just arriving from the ocean, at pigmentation stages 1–7 (established by Haro & Krueger, 1988), and elvers are defined as fully pigmented older eels that have been in continental waters for a year or more but are still less than 15 cm long. The net design excludes larger eels or other fish.

When the eels have been counted and the net reset, all eels are returned to the same tributary from which they were caught, and released above the next barrier to migration when possible, as per ASMFC protocol (ASMFC, 2000) to ensure eels are not recounted on subsequent days. While uncommon, extreme rain events may necessitate the removal of nets from the stream, but nets are ­reinstalled as soon as gear and personal safety permits.

At the end of each sampling season participants are invited to gather for “eelebrations” to share data results and stories, show appreciation to volunteers, and fill out project evaluation forms. On the evaluations, participants are asked which site(s) they sample, how frequently they sampled, if they are new or returning volunteers, to rate their knowledge and interest in the local environment before and after participating in the eel project, and to answer questions about why they decided to participate, why they care about eels, what they learned or skills they gained, and what organizers can change or do differently in the project going forward.

Analysis and quality assurance

The glass eel catch data collected across the six primary sites are examined for annual trends in catch individually and in aggregate as the Hudson River Glass Eel Index. The Hudson River Glass Eel Index is generated by taking the log total glass eels caught at each site, each year, and unit normalizing to the highest catch year before normalizing the aggregate across all sites. Assessment of trend significance of glass eels caught over the study period at each site, as well as the combined sites, is determined using a Mann–Kendall test.

The entire project has a Quality Assurance Project Plan (QAPP) based on the young-of-year sampling protocols of the Atlantic States Marine Fisheries Commission (ASMFC, 2000). Eel project volunteers are trained at each site, and new volunteers are accompanied by an experienced Eel Project mentor at all site visits to ensure proper protocol is followed. Each site has a sampling kit, including a binder with detailed pictorial descriptions of all sampling protocols. Having the methods of this project clearly standardized and transparently explained was a critical factor in the acceptance of these data by the ASMFC and state agencies. These protocols are transferable to all sites and partners and are periodically reviewed by state agency biologists and the ASMFC.

RESULTS

Volunteer experiences

Each primary sampling site differs in watershed characteristics, such as watershed size and land use, and volunteer characteristics, including volunteer base and number of volunteers (Table 1). The main volunteer audience at each location is partially determined by the location of the stream, accessibility to the stream, and partner environmental organizations and/or schools in the local area. An array of partners, including individuals, community groups, and schools, ensures a strong base of trained samplers. Many of the Hudson Valley’s tributaries have medium-sized cities near their confluence with the mainstem Hudson. This population density often includes a diverse range of socio-economic levels. The New York State Education Department publishes the percentage of students whose families participate in economic assistance programs by school, and the Eel Project works with schools that range from 27% to 73% economically disadvantaged (NYSED, 2024); thus, engaging many students historically excluded from outdoor and environmental educational experiences (Warren & Breunig, 2019). Despite differences in site geography and participant demography, robust procedures and communication ensure that data protocols are followed at all sites. Total volunteer engagement proliferated in the early years and has maintained relatively stable since then with a typical average of 800–1,000 volunteers annually across all sampling sites, including longer-term primary sites for ASMFC contribution, and additional sites with fewer years of operation.

Two of the questions from the post-season evaluations are, “Please rate your knowledge of your local stream environment before and after this project (1 = knew a little about the topic; 5 = knew a lot about the topic)” and “How interested in your local environment were you before and after this project? (1 = not at all; 5 = very much).” From these retrospective evaluations (compiled from 2012 to 2023 volunteer surveys; n = 1,562), we see that volunteers self-rated as having an increase in knowledge about their local stream environment after participating in the eel project. Volunteers self-rated as having a high interest in their local environment before the project (average 3.8), which increased after participation (average 4.6). Participants’ environmental interest was likely high even at the outset of the project since they were volunteering their time to environmental research. Volunteers who went through an entire sampling season indicated that their knowledge about their stream increased through participation in the project with an average increase from 2.6 before participation to 4.2 at the end of the season. These results are an important opportunity to identify areas of continued improvement and to assess the impact of the volunteer-related benefits of community science.

At all sites, volunteer samplers include a mix of new and returning volunteers each year. On average, 58% of volunteers are new, and 42% are returning from previous years. Most of the new volunteers each year are students, since there is a natural turnover as they graduate from high school or university. There is a strong base of returning volunteers who have been involved for many years, including teachers dedicated to bringing their new students, which helps to maintain consistency and adequate peer-to-peer training.

Eel counts

Using glass eel survey data across the six primary sites from 2010 to 2023, trends in the number of glass eels caught were assessed individually and in aggregate. Minisceongo Creek (MC), Fall Kill (FK), Black Creek (BC), Saw Kill (SK), and Hannacroix Creek (HC) all exhibited positive trends; however, the year-to-year fluctuations are generally inconsistent among sites (Figure 2). During the latter half of the survey, all sites exhibited years with extremely high glass eel influx; however, sites have different “peak” eel years throughout the survey. The only site that showed no significant change was Furnace Brook. All other sites had increasing trends that were significant to P < 0.05 using a Mann–Kendall test (MC, FK, BC, SK, HC; P = 0.018, 0.002, 0.003, 0.030, 0.006, respectively). However, given the varying physical characteristics and orientations of the mouth of each tributary relative to the Hudson River and surrounding infrastructure, and the differing fraction of which each fyke net spans its given waterway, the number of eels caught is not directly compared among sites. The eel counts provide a relative abundance index for that site over time.

The overall trend of the aggregate index portrays a log-linear positive increase in glass eel ingress through the period of the survey (Figure 3). Additionally, while the signals between sites display clear spatial heterogeneity, this variability is smoothed out when combining all sites into the aggregate index (R² = 0.71). By having multiple sites within the same river system, a more stable index is achieved, even if individual sites exhibit variability.

DISCUSSION

This study outlines a successful community science project that provides data for the stock assessment of the species and provides engagement for a range of volunteers. This effort has enabled fisheries managers to collect annual data across a range of sites within one large estuary over 14 years (and counting). The community-gathered data allowed us to identify increasing trends in eel catch (and local population by proxy) through the Hudson Valley and suggest migration patterns across tributaries to be explored in future analysis. This increasing trend in New York does not necessarily represent an overall American Eel population trend, and the increased numbers in the past 10 years are still much below historical levels (Dekker & Casselman, 2014). The random panmictic breeding of eels in the Sargasso Sea requires a comprehensive look at American Eel populations across the Atlantic coast and much more eel monitoring data (Busch et al., 1998). By utilizing community support, the reach of the Eel Project extends far beyond what agency funding sources and staff alone could support. The contribution to this robust eel monitoring data set by volunteers highlights the unique characteristics of the Hudson River Eel Project that enhance the synergistic relationships between species, volunteers, and management. These relationships can be explored through the questions: “What makes a species appropriate for community science?”; and furthermore, “What factors make community science beneficial for fisheries management?”

What makes a species appropriate for community science?

1. Wide habitat range. A wide habitat range, both in terms of overall geography and also specific habitat type, lends a species to a broad constituency of volunteer researchers. A wide distribution provides opportunities for diverse audiences to study fish and contributes to the spatial robustness of the data sets. In the case of the American Eel, their range extends along the East Coast of North America and the northern countries of South America (Benchetrit & McCleave, 2016). Across the globe, eel species are ubiquitous in many different habitats (Jacobs et al., 2003) and are found everywhere from large estuaries to tiny creeks, and from bustling cities to quiet rural areas.

2. Seasonality and frequency. Having reasonable, well-defined time commitments allow volunteers, teachers, and agencies to arrange schedules and confirm commitments, as opposed to projects where engagement is ongoing, year-round, and less well-defined. In addition, having the opportunity to experience the species studied with some regularity promotes continued interest and assuages frustration at not seeing your target animal. The annual ingress of juvenile glass eels is relatively predictable, and peaks over 2–3 months (Sullivan et al., 2006). Volunteers are organized so that any individual usually checks a net once or twice per week, with each small team of volunteers needing about 1 h to complete all tasks for a daily net check. Because glass eels migrate at the same time and often in large numbers, volunteers are very likely to catch them at some point in a season, usually quite frequently.

3. Species-specific gear. Species- or size-specific collection gear optimizes the chances of target species caught while limiting bycatch of nontarget species. This both shortens the time needed to process samples and minimizes species identification errors. The fyke nets used in the Eel Project ensure that very few organisms other than small eels are caught, especially in late winter and spring. Small fish of other species (darters [Etheostomatinae], sticklebacks [Gasterosteidae], killifish [cyprinodontiforms]) are easily distinguishable from eels, as are common invertebrates, like amphipods. Volunteers mainly have to distinguish between younger “glass” eels and slightly older elvers, which is obvious due to variance in size, shape, and color. Nets are staked in relatively shallow water at the tidal mouths of tributaries, so gear can be safely accessed with boots or waders.

4. Umbrella species for conservation. Anthropogenic impacts on ecological communities threaten almost all fauna and flora worldwide. Species across the globe require support and protection, but some species play critical roles that require more immediate action. Because they physically link oceans, estuaries, and watersheds throughout their lives, anguillid eels are an umbrella species for aquatic conservation (Itakura et al., 2020; Roberge & Angelstan, 2004). Eels also act as a lens to examine ecological stressors, across trophic gradients, active in predator–prey dynamics, and salinity gradients from the Atlantic Ocean to the tributaries of the Hudson River (Nishimoto et al., 2023). They are also a key target for habitat restoration efforts (Smith & Sutton, 2008). Hydroelectric dams threaten their spawning populations, while most other dams cut down the range of habitable space upstream (Carr & Whoriskey, 2008). In discussions of dam removals on the East Coast, eels are often at the top of the list of species that will benefit (Hitt et al., 2012; Machut et al., 2007).

5. Charisma and cultural resonance. Aesthetics and biases can dictate the degree of conservation support a threatened species receives; “attractive” and “safe” species receive more support while “ugly” and “dangerous” species are less likely to be conserved (Liordos et al., 2017). Eels suffer from a negative stereotype (Brady, 2012; Litt et al., 2021) and these low expectations add to a greater revelation of eels as interesting, important, and uniquely attractive. Many anguillid species are also in the public interest because of their unique migrations and the persistent mysteries surrounding their life histories. There are also strong cultural and culinary connections to anguillid eels worldwide. The historical and current importance of eels as a valuable food source and as a connection to rivers runs deep from North America to New Zealand (Tsukamoto & Kuroki, 2014). The eel’s ubiquitous presence in so many cultural and ecological systems makes them a perfect flagship species to promote education and social awareness, in addition to the eel’s status as an umbrella species promoting wider conservation goals.

Often these relationships between species and communities go beyond the science itself. Connections with nature and the local community, especially those that empower historically underrepresented groups, can lead to meaningful change in individual lives. The need for diversifying participants and practitioners in the sciences, especially fisheries and environmental fields, has been well noted (Arismendi & Penaluna, 2016). Many of our volunteers come from academic or socio-economic backgrounds not always included in science education and outdoor experiences (Table 1). Community science efforts like the Eel Project can sometimes be the first or only way young people get exposed to many dimensions of science at an age when they are still figuring out academic and career paths. In some cases, high school and college-aged volunteers have continued in this career path and received internships, such as the AFS Hutton Junior Fisheries Biology Program, fellowships, and permanent positions (see testimonials from past participants; Box 1). By making meaningful science accessible, community science is a “stepping stone” that gives students traction on their journey.

Research has found intangible factors, such as finding enjoyment in nature motivate continued service in the future, while enkindling a sense of community (Stukas et al., 2016). Eel Project volunteers of all ages frequently cite expanding social networks and being outside as their strongest motivations for participation (Harris et al., 2014). Volunteers also find value in the moral principle of supporting a threatened species. Our recruitment efforts emphasize internal motivators first and secondarily promote external motivations like resume building.

What factors make community science beneficial for fisheries management?

A frequent challenge of any community science project is whether the data collected are robust enough for research or management. Consistency in sampling methodology, quality control, and species identification are some of the concerns that have to be addressed when considering any monitoring program, but are even more scrutinized for community science data gathered to supplement ongoing management. Ideally, a community science project can both democratize participation as well as provide meaningful data to managers and ­policymaking agencies, such as the ASMFC. Throughout the implementation of the Eel Project and communication with both state and federal fisheries managers, a few key project elements stood out as important.

1. Simple protocols. Through the Interstate Fishery Management Plan for American Eel (ASMFC, 2000), the ASMFC established clear protocols and methodologies for its requisite young-of-year abundance monitoring to ensure standardized data collection among states and jurisdictions. There is also a practicality to the ASMFC process that allows for all members to review protocols and adjust as needed for their region, such as the start of the season or the gear used. The primary data that needs to be collected are the number of juvenile eels captured each day (with specific soak time also recorded), using consistent techniques and equipment, at the same place, and over a long (at least 10 years) time. Stock assessment scientists for the ASMFC have stated that one of the reasons they chose to include Eel Project data in the 2023 Benchmark Stock Assessment was that the protocols and methods stayed consistent over time and that we did not try to collect data or create research goals that were complicated or prone to misinterpretation by participating volunteers or management experts.

2. Management needs and critical gaps. When done correctly, community science can support ongoing species management and even address research gaps (Bonney et al., 2021). Regional utility companies were required to conduct a long-term fish monitoring program to examine and mitigate environmental impact in the Hudson River. The Longitudinal River Ichthyoplankton Survey, one of the surveys used in stock assessment and abundance estimates, ran from 1974 until it was paused in 2017, leaving a data gap in annual surveys of fish in the Hudson River estuary, including American Eel (Chang et al., 2023). At that time, the Eel Project had been established for nearly a decade and was well-regarded among state agency biologists. A state-managed glass eel monitoring site was already established on Long Island, so it made sense to fill in the gap of Hudson-specific data with a project that closely followed the same ASMFC protocols of the Long Island site. The Eel Project continues to be a strong contributor to glass eel monitoring in the state of New York.

3. Increased spatial and temporal reach. Community science extends the sampling window across space and time, better capturing these regional dynamics. As mentioned previously, some species can have extensive habitat ranges creating challenges to generate accurate population assessments by managing agencies. Environmental factors and landscape structures also play a key role in migration dynamics, creating spatial heterogeneity in the distribution of species across a given geography (Collinge, 2010; Jessop, 2003). The Eel Project highlights this variability within the estuary (Figure 2 and Figure 3). While most sites exhibit a significant increase (five of six sites) or no change (one of six sites) in the number of eels caught between 2010 and 2023 with varying migration behaviors and timings across waterways, the scale of glass eels caught among sites and their migration timings were varied. The tributary-specific variability across Hudson River sites demonstrates the necessity of multiple spatially distributed sampling sites to represent regional trends in migration more completely (Harrison et al., 2014).

4. Communication and transparency. Communication between state biologists charged with eel management, the ASMFC, and the Eel Project coordinators has been clear and frequent. Even before the Eel Project data was accepted into the ASMFC process, the engagement value of community science was well-recognized and sometimes featured on the agency website. Early development of a QAPP vetted by a third-party process was facilitated by good communication and constructive comments from the ASMFC and multiple state partners (NEIWPCC, 2023). This QAPP process directly involved feedback and constructive criticism from agency partners and academic experts, which both strengthened the project itself and created better understanding and acceptance from the partners. When the project reached the 10 years of data collection needed for consideration by the ASMFC, it was already a known effort on the landscape of fisheries monitoring and education. The ASMFC also provided clear communication, as they informed Eel Project managers of the multiple steps involved including reviews by technical committees.

Key takeaways

Eels are a compelling species for volunteer-based monitoring, given their wide species range, seasonality, umbrella and flagship species status, unique life history, potential for perception change, and ability to inspire future outdoor educators and scientists. This unique combination of traits can also help to bring in audiences that are often underrepresented in science education and build bridges to the next generation of environmental stewards and eel supporters. Aligning these goals of education, stewardship, and management while maintaining the integrity of the monitoring protocol can be difficult, but we have demonstrated how the Hudson River Eel Project is well-suited for this challenge. Using simple protocols, promoting transparency in communication, and addressing critical management needs, the Eel Project provides necessary and robust data for the continued conservation of this elusive data-poor species.

Our eel data show that spatially distributed net sites are crucial to ascertaining a comprehensive picture of regional eel populations. While this paper largely focuses on the interaction between eels and community science, we show that eel numbers in the Hudson Valley have increased over the past 10 years. Investigating the factors driving this rise will be the focus of future investigation as it is beyond the scope of this paper. All migratory fish will continue needing conservation efforts as dams, pollution, and climate change continue to hamper their ability to complete their life history. Community volunteers and researchers alike will need to continue to be called upon to protect these mysterious fish. Like our volunteer t-shirt says…“Long Live Anguilla!”

Community science for fisheries monitoring comes with challenges: data collection must be accurate, and precious agency staff time has to be devoted to everything from volunteer recruitment to database management. However, with deliberate organization, agency buy-in, and robust protocols, community science can be a great asset to fisheries ­management, increasing the temporal and spatial scale of data collection as well as public buy-in and interest. Although this case study has focused on eels in the Hudson River, the lessons learned from applying community science to management and monitoring are widely applicable to eels and other fish species worldwide.

DATA AVAILABILITY

Eel count data and date/time are available upon reasonable request to the corresponding author. Specific sampling locations are not available for American eel protection purposes.

ETHICS STATEMENT

The research presented adheres to the ethical standards of the American Fisheries Society and complies with all relevant laws and regulations in New York State and Richmond, Bronx, Westchester, Rockland, Putnam, Orange, Dutchess, Ulster, Greene, and Rensselaer Counties, and AFS Guidelines for Uses of Fishes (5.2 and 5.3). All eel handling procedures follow protocols for fish welfare, and collection methods were designed to minimize impacts on the eels and support the health of the population. Informed consent and NYSDEC volunteer applications were obtained from volunteers when necessary, and the research was conducted with a focus on protecting the species and supporting the community. All work were completed under a NYSDEC Scientific License to Collect or Possess #1485.

FUNDING

Funding for this project comes from the New York State Department of Environmental Conservation Hudson River Estuary Program and Hudson River National Estuarine Research Reserve, in partnership with Cornell University and NEIWPCC.

ACKNOWLEDGMENTS

Thank you to the Delaware Nation, Delaware Tribe of Indians, Munsee–Delaware Nation, and Stockbridge–Munsee Band of Mohican Indians, whose homelands and waters surround this research. Thank you to Ben Maracle and Aishwarya Shankar for graphics assistance. Stephen Morreale, Alex Flecker, and Suresh Sethi provided guidance and direction. This project is possible because of the environmental educators, teachers, group leaders, and volunteer samplers who come to the streams. This work is shared with every one of you, thank you!

REFERENCES

Author notes