To effectively conserve freshwater fishes, conservationists need information on what types of habitats a given fish species requires. Freshwater migratory species are unique compared to non-migratory fishes because they require access to two or more distinct habitats to complete their life cycles. Ensuring that multiple habitats are suitable and that access between habitats exists can make the job of protecting migratory fishes challenging.
Conserving migratory fishes may also be difficult for another reason. Researchers do not have a full understanding of many migratory species’ life histories. Of those fishes that are known to or suspected of migrating, the specific habitat needs of relatively few of these species are fully-described in the literature, with well-described species tending to be those that are economically or socially important (e.g., Pacific salmon). Improving our understanding of lesser known migratory fishes is an important step for their conservation.
To aid in addressing these challenges, we assembled the state of knowledge on freshwater migratory fish species into a comprehensive database, the North American Freshwater Migratory Fish Database (NAFMFD). The NAFMFD was created with information from peer-reviewed literature, gray literature, and fish ecology databases. The NAFMFD synthesizes the migration status for approximately 1,215 freshwater fish species, including whether or not species are migratory, and if migratory, the type of migration pattern the species exhibits.
Preliminary analyses of our database highlights the diversity of migratory freshwater fishes. Approximately 28% of species are migratory, 50% are non-migratory, and 22% do not have their migration pattern described. While many migratory fish species typically exhibit only one type of migratory pattern, we integrated reports from multiple sources in the NAFMFD to show how some species exhibit multiple migratory patterns. For example, shortnose sturgeon (Acipenser brevirostrum) have been reported to be anadromous throughout their range in rivers of the Atlantic Coast, yet they also exhibit both potamodromous and amphidromous patterns within the same region. We have also found cases where species listed as non-migratory in some sources are described as migratory by others including, for example, the Colorado pikeminnow (Ptychocheilus lucius) which has been described by some as making substantial migrations throughout the Colorado River system.
The information in the database can be used by researchers and managers to gain a richer understanding of habitats that fish species need. Figure 1 shows families with more than 40% of their species identified as endangered, threatened, or vulnerable in 2008 (Jelks et al. 2008). Our summary of information in the NAFMFD shows that all species of sturgeons and lampreys, most species of suckers and salmon and trout, and some species of catfishes, perches and darters are migratory. Consistent and comprehensive knowledge of the type of migration patterns exhibited by imperiled species in these families can aid in their conservation.
Figure 1. Migration status of fish species in families with >40% imperilment.
This database is currently in review by regional experts on migratory fishes, and we plan to publish the first version of this database in the coming year. Ideally, this database can be updated regularly as new information on migratory status of undescribed species becomes available to facilitate research and aid in conservation efforts of freshwater migratory fishes. Please contact Emily Dean at [email protected] for more information.
Source: Jelks HL, Walsh SJ, Burkhead NM, Contreras-Balderas S, Díaz-Pardo E, Hendrickson DA, Lyons J, Mandrak NE, McCormick F, Nelson JS, Platania SP, Porter BA, Renaud CB, Schmitter-Soto JJ, Taylor EB, and Warren ML Jr. 2008. Conservation status of imperiled North American freshwater and diadromous fishes. Fisheries 33:372-407.
Biographies: Emily Dean ([email protected]) is a doctoral student in the Department of Fisheries and Wildlife at Michigan State University. Her research interests include fish habitat conservation and migratory fish ecology. Dana Infante ([email protected]) is an Associate Professor in the Department of Fisheries and Wildlife at Michigan State University. Her research interests include understanding influences on river habitats and fishes they support and identifying opportunities for river fish conservation.