Environmental Biology of Fishes

, Volume 7, Issue 4, pp 341–347

The bull shark (Carcharhinus leucas) and largetooth sash (Pristis perotteti) in Lake Bayano, a tropical man-made impoundment in Panama

  • Rafael Vásquez Montoya
  • Thomas B. Thorson

DOI: 10.1007/BF00005568

Cite this article as:
Montoya, R.V. & Thorson, T.B. Environ Biol Fish (1982) 7: 341. doi:10.1007/BF00005568


The Río Bayano in eastern Panama is one of many tropical rivers in which bull sharks (Carcharhinus leucas) and largetooth sawfish (Pristis perotteti) have been known to occur. Since both species can osmoregulate in fresh water throughout life, theoretically, both could survive in landlocked situations for many years.P. perotteti reproduces in fresh water, butC. leucas ordinarily does not, so only the former would appear to have the potential for establishing a breeding stock in such a landlocked freshwater body.

The damming of the Rio Bayano and the creation of a large impoundment in 1976 provides a test of the ability of members of both species trapped there to survive and to establish breeding stocks. In 1980 and 1981 three mature femaleC. leucas were found dead in Lake Bayano and three sub-adult femaleP. perotteti were taken by trammel net. These events confirm the ability of both to survive in fresh water for long periods, but the establishment of breeding stocks appears doubtful and the question may not be answered for many years.


ElasmobranchiiEuryhalinityFreshwater adaptationDam lakeOsmoregulationCentral America

Copyright information

© Dr W. Junk Publishers 1982

Authors and Affiliations

  • Rafael Vásquez Montoya
    • 1
  • Thomas B. Thorson
    • 2
  1. 1.Centro de Ciencias del Mar y LimnologiaUniversidad de Panamá, Ciudad UniversitariaPanamáRP
  2. 2.School of Life SciencesUniversity of Nebraska-LincolnLincolnUSA