Factors Affecting Larval Sea Lamprey Growth and Length at Metamorphosis in Lampricide-Treated Streams
Citation
RONALD W. GRIFFITHS, F. W. H. BEAMISH, B. J. MORRISON, AND
L. A. BARKER. Factors Affecting Larval Sea Lamprey
Growth and Length at Metamorphosis
in Lampricide-Treated Streams. Transactions of the American Fisheries Society 130:289–306, 2001
q Copyright by the American Fisheries Society 2001
Summary
Abstract.—Larval sea lampreys Petromyzon marinus in seven lampricide-treated streams were studied to assess the effects of density and abiotic factors on growth, length at metamorphosis, and age at metamorphosis. Support for density-dependent growth was not found in these streams. A linear relationship between total length and age was found for all populations. The daily growth of larvae in lampricide-treated streams was similar to that of populations that were never exposed to lampricide. Furthermore, the growth of stocked residual populations did not increase following a lampricide-induced reduction in larval density. Differences in growth and length at metamorphosis among these streams were accounted for by abiotic factors. Larval [...]
Summary
Abstract.—Larval sea lampreys Petromyzon marinus in seven lampricide-treated streams were
studied to assess the effects of density and abiotic factors on growth, length at metamorphosis,
and age at metamorphosis. Support for density-dependent growth was not found in these streams.
A linear relationship between total length and age was found for all populations. The daily growth
of larvae in lampricide-treated streams was similar to that of populations that were never exposed
to lampricide. Furthermore, the growth of stocked residual populations did not increase following
a lampricide-induced reduction in larval density. Differences in growth and length at metamorphosis
among these streams were accounted for by abiotic factors. Larval growth was highest in
streams with an annual water temperature around 88C, moderate discharge (0.5–2.0 m3/s), and
high conductivity (.300mS). Length at metamorphosis, on the other hand, was inversely related
to conductivity, annual discharge, and annual mean temperature. A model of age at metamorphosis
based on larval growth and length at metamorphosis, both as functions of water temperature,
showed that age at metamorphosis was lower for populations showing linear growth with age
(typically low-density populations) than for those showing compensatory growth with age (typically
high-density populations).
