Cooperative Research Units
Education, Research And Technical Assistance For Managing Our Natural Resources
Home | Intranet | Digital Measures | Help

Grabowski T.B. and J.J. Isely. 2008. Size of spawning population, residence time, and territory shifts of individuals in the spawning aggregation of a riverine catostomid. Southeastern Naturalist 7:475-482.

Staging robust redhorse on their spawning grounds in the Savannah River, South Carolina - Georgia.


.— Little is known about the behavior of individual fish in a spawning aggregation, specifically how long an individual remains in an aggregation. We monitored robust redhorse Moxostoma robustum (Cope) in a Savannah River spawning aggregation during spring 2004 and 2005 to provide an estimate of the total number of adults and the number of males comprising the aggregation and to determine male residence time and movements within a spawning aggregation. Robust redhorse were captured using prepostioned grid electrofishers, identified to sex, weighed, measured and implanted with a passive integrated transponder. Spawning aggregation size was estimated using a multiple census mark and recapture procedure. The spawning aggregation seemed to consist of approximately the same number of individuals (82-85) and males (50-56) during both years of this study. Individual males were present for a mean of 3.6 ± 0.24 days (± SE) during the 12-day spawning period. The mean distance between successive recaptures of individual males was 15.9 ± 1.29 m (± SE). We conclude that males establish spawning territories on a daily basis and are present within the spawning aggregation for at least 3-4 days. The relatively short duration of the aggregation may be the result of an extremely small population of adults. However, the behavior of individuals has the potential to influence population estimates made while fish are aggregated for spawning.


Current Staff

Federal Staff: 2

Masters Students: 5

Phd Students: 4

Post Docs: 0

University Staff: 2

5 Year Summary

Students graduated: 43

Scientific Publications: 67

Presentations: 156



July (3rd Quarter/Summer) 2008


Publisher Website

Unit Authors

Texas Cooperative Fish and Wildlife Research Unit Cooperators

  1. Texas Parks and Wildlife
  2. Texas Tech University
  3. U.S. Fish and Wildlife Service
  4. U.S. Geological Survey
  5. Wildlife Management Institute