Latitudinal Variation in Lake Sturgeon Size as Related to the Thermal Opportunity for Growth
作者:
M. Power,
R.S. McKinley,
期刊:
Transactions of the American Fisheries Society
(Taylor Available online 1997)
卷期:
Volume 126,
issue 4
页码: 549-558
ISSN:0002-8487
年代: 1997
DOI:10.1577/1548-8659(1997)126<0549:LVILSS>2.3.CO;2
出版商: Taylor & Francis Group
数据来源: Taylor
摘要:
The relationships between age-specific total lengths, weights, condition factors, and a measure of the thermal opportunity for growth (TOG; calculated as the sum of degree-days greater than 5°C) were estimated for lake sturgeonAcipenser fulvescensfrom data available for 16 populations spread throughout much of the species' natural range. The TOG explained a significant proportion of the observed variation in length at age irrespective of age. Correlations between weight at age and condition factor improved significantly as lake sturgeon aged, although TOG remained a poor indicator of the differences in condition at age among sturgeon populations. As elsewhere in the literature, declines in length and weight at age occurred at higher latitudes. However, growth rates (mm/degree-day), when adjusted for TOG, showed a significant inverse relationship between growth rates and latitude. The latitudinal countergradient in growth rates partially compensates for reduced growth opportunities in northern populations of lake sturgeon.
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