Establishing a Network of Eel Ramps to Monitor Recruitment of Glass and Elver American Eel

Purpose/Objectives

The objectives of this research are to build, install, monitor, and provide maintenance for up to 12 eel ramps along the central to upper Texas Coast to assess the current status of American eel in Texas. Detections of glass or elver American eels will be critical in elucidating recruitment timing, distribution, and abundance of this species of greatest conservation need. The results of this work will support conservation needs outlined in the Texas Conservation Action Plan, particularly for investments in conservation actions (research and monitoring), priority habitats (restoration and protection of instream aquatic habitats), and priority issues (conservation planning and regulatory actions) related to the conservation of freshwater fish diversity in Texas (TPWD, 2012b).

Study Area

Central to upper Texas coast (Matagorda, Galveston, and Sabine Bay systems and adjacent coastal areas)

Project Period

2022 - 2025

Description

The American eel (Anguilla rostrata) is a catadromous panmictic species of greatest conservation need in Texas. In-water diversions and water control structures pose a potential threat to American eel because of their highly migratory, catadromous life history. An important area of study is the recruitment of juvenile (glass eel and elver) stages to the coastal waters of the state. This recruitment or ingress of glass eels and elvers is likely to regulate the long-term local population success of the species. Recently, extensive field efforts to document recruiting American eels along the Texas coast have not been successful at detecting any individuals. As a result, recommendations to explore other novel methods to document recruitment along the Texas coast have been made. The findings of those field studies suggest that a continuous-passive gear deployment (e.g., eel ramps) be utilized to build upon past efforts to document recruitment along the Texas coast.

During this study EIH researchers will construct and deploy 10 to 12 eel ramps specially designed to target ingressing glass eels and elvers along the central to upper Texas Coast with weekly checks for one year. Based on the initial recruitment window identified in year 1, two additional years of sampling will be conducted, focused on the recruitment window with more frequent ramp checks. Year 2 and 3 will be focused on the site conditions that were most successful in year 1. These data will provide baseline information for detecting the spatial and temporal recruitment of American eel to the Texas Gulf Coast. This critical information will assist natural resource agencies in determining the conservation and management needs of American eel populations in Texas.

Publications and Presentations

Oakley, J.W., Curtis, S., Hansen, J., Sak, A., Underwood, E., Swinford, J., Anderson, J., and Guillen, G. 2022. Determination to detect recruitment of American eel (Anguilla rostrata) in Texas. Texas Bays and Estuaries Meeting, Port Aransas, TX. Poster.

Oakley, J.W., Curtis, S., Swinford, J., Sak, A., Underwood, E., Kean, P., Anderson, J., Davis, S., Fredrickson, A., and Guillen, G. 2023. Eel ramps and eDNA to detect recruitment of American eel (Anguilla rostrata) in Texas. Annual Meeting of the Texas Chapter of the American Fisheries Society, Corpus Christi, TX. Poster.

Sak, A., Underwood, E., Oakley, J.W., Curtis, S., Kean, P., Swinford J., Anderson, J., Davis, S., Fredrickson, A., and Guillen, G. 2023. Determining recruitment timing and distribution of American eel (Anguilla rostrata) in Texas utilizing eel ramps. Houston Regional Ecology & Evolution Symposium, La Marque, TX. Presentation.

Project Sponsors and Partners

• Texas Parks and Wildlife Department, River Studies Program
• Texas Parks and Wildlife Department, Coastal Fisheries
• Texas Parks and Wildlife Department, Perry R. Bass Marine Fisheries Research Center
• Lower Colorado River Authority

Related links

Distribution, Abundance, and Habitat Use of the American Eel

From sea to stream: tracking the elusive American eel as it slithers from Texas’ estuaries into its rivers, Texas Saltwater Fishing Magazine

Glass eels found in Texas for the first time, Texas Parks & Wildlife Magazine