American Eel Subpopulation Characteristics in the Potomac River Drainage, Virginia

The demographic characteristics of American eels (Anguilla rostrata) are believed to vary with latitude and distance inland from the ocean; eels are generally thought to increase in length, age, and the proportion of females in inland and more northerly areas. Understanding this variation is necessary for the sound management of eels, but investigations into characteristics on a broad scale within drainages are scarce. Eels in the Potomac River drainage, Virginia, were sampled over a two-year period in both near-coastal and inland areas to describe characteristics in each area as well as to understand drainage-wide patterns. Inland data resulted from sampling in the Shenandoah River drainage and near-coastal data resulted from sampling tributaries to the lower Potomac River. Movement and growth were also investigated in inland areas. Eels from the Shenandoah River drainage were significantly longer (median = 763 mm TL) and older (median = 11.5) than those found in the Potomac River tributary sites (median = 142 mm TL; median = 2.0, respectively). Both total length and age increased with increasing distance inland and sex ratio shifted from varying ratios of males:females in Potomac River tributaries to all females in the Shenandoah River drainage. Movements confirmed through mark-recapture over periods ranging up to one year were short, generally <100 m, with the longest detected movement being 1.5 km. Recapture rates were low and may be due either to low sampling efficiency, long-distance movements, or a combination of these factors. Growth and 95% confidence interval from five eels recaptured after approximately one year was 43.0 +/- 29.7 mm/year. CPUE decreased with increasing distance inland, confirming information reported by others for Virginia streams.

Name thesis:degree_name

Master of Science

Level thesis:degree_level

masters

Discipline thesis:degree_discipline

Fisheries and Wildlife Sciences

Department dc:contributor.department

Fisheries and Wildlife Sciences

Grantor dc:publisher

Virginia Tech

Year dc:date.issued

1999

Author dc:creator

• Goodwin, Kevin R.

Chair dc:contributor.committeechair

• Angermeier, Paul L.

Committee members dc:contributor.committeemember

• Dolloff, C. Andrew
• Orth, Donald J.

• movement
• dams
• electrofishing
• mark-recapture
• growth
• freshwater
• age
• total length
• eel

Statement dc:rights

• In Copyright

Licence dc:rights.uri

• http://rightsstatements.org/vocab/InC/1.0/

Dc Identifier Other

etd-071699-161918

OAI identifier oai:identifier

oai:vtechworks.lib.vt.edu:10919/34036