Migratory Freshwater Fishes: Global Status Update and Swimway Initiative (hosted by AFS)

Migratory freshwater fishes around the world play crucial roles in supporting human populations by providing nutrition and income, and sustaining ecosystem health via mechanisms that include terrestrial-aquatic linkages, such as nutrient transport and food web stabilization. Despite their importance, often little is known about the status of their populations and conservation needs (He et al. 2018), and they are rapidly being eliminated from much of their natural range. Their beneficial movement patterns make migratory fish highly susceptible to a host of increasing threats, such as overfishing, physical migration barriers, and water quality and flow alterations. Many populations have dramatically declined (Limburg and Waldman 2009) and more are expected to follow as threats mount (Winemiller et al. 2016). Globally, there is an urgent need for (1) quantitative assessments of migratory freshwater fishes to evaluate their conservation statuses and guide management and conservation planning, and (2) an integrated, collaborative conservation platform. This symposium will start to meet those needs by calling attention to the global status of migratory freshwater fish populations, and introducing the Global Swimway Initiative – a long-lasting global cooperation to fill knowledge gaps and inspire people to protect and open up migration routes. The symposium will include talks highlighting the global status of migratory fishes and swimways, and end with a discussion of session outcomes and future steps towards filling knowledge gaps and achieving sustainability. We invite talks that present quantitative assessments of the conservation status of migratory freshwater fish populations (e.g. results of monitoring programs, stock assessments, population viability analyses, updated IUCN red list assessments, etc.), and that highlight swimway statuses and initiatives. As migratory fishes affect people and whole ecosystems worldwide, the exchange of information and ideas in this session will be of interest to a wide audience within the AFS and TWS communities.

8:00AM Introductory Remarks
  Zeb Hogan
8:20AM Declining Stocks – Why We Need the Concept of Global Swimways
  Arjan Berkhuysen, Kerry Brink
Ongoing river fragmentation and dam construction are two of the greatest global threats to freshwater biodiversity, migratory fish and ecosystem functioning. Responses on climate change will most likely worsen the situation, as more barriers can be expected to be built. We believe it’s time for a Global Swimways Initiative: First, life in water deserves more attention worldwide. The awareness on migratory fish is currently too low, resulting in knowledge gaps regarding conservation and management of swimways. Second, as a result conservationists are not enough involved in adaptation of our coastlines and waterways, where a lack of nature-inclusive policy guidelines allows new and obsolete dams to block swimways and destroy important habitats. Therefore, we need to learn from the ‘flyways’ concept. This concept has been extremely successful to involve people with migratory birds, to increase collaboration between scientists and conservationists and to trigger global conservation agreements like Ramsar. The Living Planet Index for migratory fish from 2016 shows a serious decline in abundance. However, there is also a sign of hope, because river conservation and restoration have shown to be extremely effective to turn the tide. A Global Swimways Initiative should bring us together to act, backed by science.
8:40AM Global Review of Migratory Freshwater Fish: An Updated Assessment of Options for Listing on the Appendices of the U.N. Convention on Migratory Species
  Zeb Hogan
Growing evidence shows that migratory freshwater fish species are among the most imperiled in the world. This updated review assesses the conservation status of migratory freshwater fish to determine which species would likely benefit from listing on the Convention on Migratory Species Appendices. Based on data from Fishbase and IUCN, a list of species was generated that meet CMS listing criteria: migratory, transboundary freshwater fish with unfavorable conservation status. Species assemblages that would likely benefit from listing include sturgeon and salmon, sawfish (Pristiformes), freshwater stingrays, anguillid eels (Anguillidae), shad (Alosinae), and large, migratory pimelodids and characids of South America, pangasiid catfish of Southeast Asia, mahseer (Tor spp. and related species), and Alestiidae of the Lake Chad basin. This review highlights the importance of several actions to improve the management and conservation status of migratory fish, including: 1) development of baseline information on current and historical abundance of migratory fish; 2) improvement of knowledge of migratory fish ecology; 3) mitigation of problems created by damming; 4) reduction of habitat degradation, including pollution; 5) initiation of trans-boundary monitoring and management programs in partnership with other management frameworks and including regional migratory fish workshops and data sharing.
9:00AM Realizing the Future of Fish Passage Science, Engineering, and Practice
  Steven J. Cooke
Much effort has been devoted to developing, constructing and refining fish passage facilities to enable target species to pass barriers on fluvial systems, and yet, fishway science, engineering and practice remain imperfect. I will report on a review that involved seventeen experts from different fish passage research fields (i.e., biology, ecology, physiology, ecohydraulics, engineering) and from different continents (i.e., North and South America, Europe, Africa, Australia) where we identified knowledge gaps and provided a roadmap for research priorities and technical developments (i.e., Silva et al. 2018 – Fish and Fisheries). I will further extend the ideas we shared in that paper to consider how we embrace and adopt them to yield meaningful improvements in fish passage science, engineering and practice that benefit fish populations.
9:20AM Global Swimways: Definitions and Status
  Leopold Nagelkerke, Arjan Berkhuysen, Kerry Brink, Steven Cooke, Stefanie Deinet, Britas Klemens Eriksson, William Twardek
The swimway concept was coined by the World Fish Migration Foundation in analogy to the flyway concept for migratory birds. The flyway concept has been widely studied at different spatial scales and taxonomic levels (ranging from single-species to multi-species migration routes), and knowledge on the extent and status of flyways is increasing fast. Moreover, the concept has become widely used in conservation plans for migratory bird species. The swimway concept could play a similar role in the conservation of migratory fish species. However, despite its communicative and intuitive strengths, the swimway concept, until now, lacks clear definition(s), and it is insufficiently known at what spatial scales, and for which species it is applicable. Moreover, for many fish species around the world even basic biological and environmental information, such as on migratory behaviour and habitat, is lacking. This hampers the applicability of the swimway concept in conservation, and stresses the urgency of the directed collection of data to operationalise it. The existing definitions of the swimway concept, the spatial scales at which it could be applicable, species to include, and research priorities to further develop the swimway concept will be discussed in this presentation.
09:40AM Break
1:10PM The Unnatural History of Fish Migrations in the Laurentian Great Lakes, and Needs for Strategic Restoration
  Peter McIntyre, Solomon David, Ashley H. Moerke, Evan Childress, Thomas Neeson, Allison Moody, Matthew E. Herbert, Mary Khoury, Patrick J. Doran, Matthew Diebel, Michael Ferris, Steven Wangen, Karen J. Murchie
More than fifty species of native fishes once made annual migrations into tributaries of the Laurentian Great Lakes to spawn. Today, many of these migratory populations are gone, while others have remained robust, and some are even expanding. Restoring this diverse suite of migrants to their former abundance would benefit both fisheries and ecosystems. However the man-made barriers that block access to most of the tributary network also serve to limit the spread of invasive fishes. We will provide an overview of the losses and gains of migratory fishes, and offer a framework and toolkit for prioritizing restoration of swimways within this large system. Long-term restoration success requires public support, and we will also discuss a citizen science approach to enhancing awareness of the existence and benefits of fish migrations.
1:30PM The North American Freshwater Migratory Fish Database (NOAMAD): Characterizing the Migratory Patterns of Freshwater Fishes of Canada, the United States, and Mexico
  Emily Dean, Dana Infante
More than 1100 freshwater fish species occur throughout North America, with species from approximately 50 families including migratory fishes. Migratory fishes must access distinct habitats to complete their life cycles, and because of this, successful management requires protecting those habitats and connections between them. Management of migratory fishes is also challenging because life history characteristics of many fishes are not widely-known; only a few socioeconomically-important species are fully-described in the literature. To aid in addressing this limitation, we assembled the state of knowledge on freshwater fish migratory life history patterns into a comprehensive database, the North American Freshwater Migratory Fish Database (NOAMAD). We used published and gray literature, fish ecology databases, and expert opinion to describe migratory life history patterns for all North American freshwater fishes. Our results show that 403 species are known long-distance migrants, with another 171 suspected migrants. Of known migrants, 224 are exclusive in their migratory pattern (145 potamodromous, 41 anadromous, 29 amphidromous, 9 catadromous), while 179 fish species exhibit multiple life history patterns. Our results highlight the diversity of migratory fishes as well as complexity in their life history patterns, contributing to efforts to conserve migratory fishes from freshwater habitat fragmentation across North America.
1:50PM Coupling Migratory Fish Distribution Models and Large Dam Data to Prioritize Fish Passage Restoration: A Case Study in the Upper Mississippi River
  Arthur R. Cooper, Dana Infante
While ecological aspects of dam removal and fish passage mitigation have been explored, analyses of potential mitigation actions often only consider generic longitudinal river connectivity as a potential measure of habitat improvement. We provide a case study highlighting the use of fish species distribution models to assess species-specific prioritizations based on predicted habitat suitability for six migratory fishes of conservation concern in the Upper Mississippi River (UMR). Utilizing information on predicted fish distributions, stream fragmentation by large dams, and cost estimates for dam removal and fish passage mitigation, prioritizations are developed for the UMR under multiple scenarios: dam removal only, fish passage construction only, and a blended, most cost-efficient approach. Of the 2,603 large dams in the UMR, 333 are projected to block habitat access for one or more species, fragmenting habitats into as few as 9 and 13 discrete river segments with > 25 rkm of predicted habitat for Lake Sturgeon and Paddlefish, respectively. Compared to generic, river length-based prioritizations, approaches that integrate species distribution models generate species-specific estimates of habitat improvement and can provide more efficient outcomes in dam removal and fish passage mitigation actions targeting multiple species of conservation importance.
2:10PM Caught between a Rock and a Hard Place: Monitoring Chinook Salmon in California’s Central Valley
  Tyler J. Pilger, Dana Lee, Matthew Peterson, Andrea Fuller, Doug Demko
Chinook salmon (Oncorhynchus tshawytscha) undertake some of the most well-known and well-studied migrations in the animal kingdom. Following extensive migrations through riverine and marine environments, salmon in California’s Central Valley return to highly altered and spatially constrained freshwater spawning habitats. Millions of dollars are spent annually to monitor these migrations and mitigate the effects of habitat loss and hydropower operation on freshwater spawning and rearing habitat. Yet, populations remain imperiled due to increasing water temperatures, water diversions, channel alterations, high predation rates, and replacement of wild stocks with straying hatchery stocks. The Stanislaus River has one of the most comprehensive and longest running life-cycle monitoring programs in the Central Valley. Monitoring activities are designed to track the abundance, distribution, migration characteristics, and habitat use of Chinook salmon, using a variety of different sampling methods and technologies. Rotary screw trap monitoring is used to characterize juvenile downstream migration, while a fish counting weir is used to monitor upstream migration of adults. Snorkel and seining surveys document abundance and habitat use, redd and carcass surveys document spawning, collect biological samples and coded-wire-tags. These data will inform flow management and habitat enhancement to provide suitable conditions for multiple life stages of Chinook salmon.
2:30PM Population Dynamics of Threatened Lahontan Cutthroat Trout in Summit Lake (USA)
  James Simmons, Teresa Campbell, Christopher Jerde, Sudeep Chandra, William Cowan, Zeb Hogan, Jessica Saenz
Summit Lake (Nevada, USA) is home to one of the last two self-sustaining adfluvial populations of threatened Lahontan cutthroat trout (Oncorhynchus clarkii henshawi). The trout are of significant cultural importance for the Paiute people indigenous to the Summit Lake area. From spring 2015 to fall 2017, we quantified adult abundance and survival and the total annual spawning run. Abundance and survival were estimated with a robust design mark-recapture effort using passive integrated transponder (PIT) tags. The total annual spawning run was estimated by counting fish in the sole spawning tributary. The estimated adult abundance decreased during the study period from 2174 (profile likelihood CI 1039-4889) to 972 (profile likelihood CI 632-1548) individuals. However, female abundance increased while male abundance decreased. Adult survival was 0.48, with female survival 0.60 and male survival 0.31. The spawning run increased from 645 in 2015 to 879 in 2016, but then decreased slightly to 827 in 2017. Likewise, female spawners increased in 2016 but decreased slightly in 2017. However, male spawners decreased each year. The declining abundance, divergence of female and male abundance and spawning numbers, and low survival rates were likely caused by severe regional drought conditions in the western US.
2:50PM Refreshment Break
3:20PM Free-Flowing Rivers & Migratory Fish Status for Southern Africa
  Kerry Brink, Michele Thieme, Guenther Grill, Bernhard Lehner, Ian Harrison, Agness Musutu, Faith Chivava
Knowledge of migratory fish is biased towards developed countries. In Africa, the current status of migratory fish and their conservation needs is still very much unknown. With new dam and infrastructure development across Africa, which can have a significant impact on freshwater ecosystems, there is an urgent need for information to support conservation and restoration efforts. We will first provide an overview of the status of long free-flowing rivers for the region. We define free-flowing rivers as those where ecosystem functions and services are largely unaffected by changes to fluvial connectivity allowing unobstructed movement of water, energy, material and species within the river system and with surrounding landscapes. To gain insights into the current status of migratory fishes, a review of 249 freshwater fishes from southern Africa was conducted. Approximately 130 species were identified to need migration for their survival, but at the same time, most species were severely data deficient. In this presentation, we will give an overview of the status and migration routes of fishes in Southern Africa, of the research and conservation trends uncovered, highlight key areas of action, and present an example of targeted work already underway for the free-flowing Luangwa River in Zambia.
3:40PM Migratory Fish and Tributary Dams in the Mekong: What Do We Actually Know?
  Eric Baran, Zeb Hogan
The Lower Mekong Basin is characterized by a very high fish production (circa 2.1 million tonnes) and large-scale fish migrations, with at least 165 species involved. The negative impact of mainstream dam development on fish production and biodiversity has been repeatedly underlined and documented, but very few studies have addressed the impact of tributary dams on the fish resource. A review of 71 fish species lists shows that species distribution is known in twelve Lower Mekong sub-basins, out of 104 sub-basins identified. In contrast, 101 hydropower dams are built or currently under construction in the Lower Mekong tributaries. We review the current state of knowledge about the impact of tributary dams on fish migrations in the Lower Mekong Basin, highlight knowledge gaps, and identify research needs in this region.
4:00PM Migratory Freshwater Fishes in South Asia: Status, Trends and Opportunities
  Rajeev Raghavan
4:20PM What Goes up Must Come Down: Developing a Conservation Strategy for Migratory Fish in Bhutan
  Julie Claussen, Karma Wangchuk, D K Gurung, Jigme Tsuendrup, Marlis Douglas, Michael Douglas, David Philipp
Human development along rivers has taken a heavy toll on the world’s migratory fish species. In addition, effective conservation planning has been severely impeded by the lack of basic biological information on many river fishes. Bhutan, a small Himalayan country bordered by China and India, currently has rivers free from dams, offering a rare opportunity to study the natural migration of two their species: the Chocolate Mahseer (Neolissocheilus hexagonolepis) and the Golden Mahseer (Tor putitora). A joint international partnership in Bhutan has been focused on filling the information gaps on these species, especially before any large-scale development impacts their migration. For the last four years, this project has used radio-telemetry to track fish movement and has made significant headway in understanding the migration pathways, seasonal movements, and spawning locations for both species. The project is working closely with government agencies with the hope that these data will drive science-based resource planning to protect and conserve mahseer populations.
4:40PM Migratory Fish from the Neotropics: Conservation Status, Threats, and Management Pitfalls
  Luiz Gustavo M. Silva
The Neotropics is home for over 4,000 fish species and, therefore, the most diverse bioregion in the world. Globally, it contains two of the most diverse ichthyofaunal provinces namely the Amazonian (~2,416 sp.) and the Paranean (~ 847 sp.). Therefore, it is also home for the great diversity and life-histories, especially of migratory and reophilic species. The two major groups of migratory species include the Characiformes and Siluriformes with small to large bodied fish with different migratory behaviours. Such behaviours include short-distance migrants (migrate less than 100 km or perform lateral movements) and long-distance migrants. In the last decade, with the advancement of technology to study migratory movements, a very complex set of behaviours started to be revealed for various species at different river basins. Unfortunately, most of this information was obtained at altered areas and locations where the conservation status for those species was of major concern. Most of migratory Neotropical fish populations are declining, with increasing number of species listed under a certain threat category. In this talk I will discuss the conservation status and ecology of some of the most iconic migratory Neotropical species, as well as the main threats and potential management pitfalls for their conservation.
5:00PM Panel Discussion
  Arjan Berkhuysen

Organizers: Teresa Campbell, Herman Wanningen, Kerry Brink, Erin Loury, Zeb Hogan, Shaara Ainsley, Arjan Berkhuysen
Supported by: Wonders of the Mekong Project (providing Teresa’s time to organize the symposium); FISHBIO (providing Erin and Shaara’s time to organize and moderate); World Fish Migration Foundation (providing Arjan, Herman, and Kerry); International Fisheries Section

Location: Reno-Sparks CC Date: September 30, 2019 Time: 8:00 am - 5:20 pm