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Comparison of Age and Growth Estimates for River Carpsuckers Using Scales and Dorsal Fin Ray Sections
Author(s) -
Braaten Patrick J.,
Doeringsfeld Matthew R.,
Guy Christopher S.
Publication year - 1999
Publication title -
north american journal of fisheries management
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.587
H-Index - 72
eISSN - 1548-8675
pISSN - 0275-5947
DOI - 10.1577/1548-8675(1999)019<0786:coaage>2.0.co;2
Subject(s) - age groups , fish <actinopterygii> , dorsal fin , fish fin , fin , demography , age structure , biology , fishery , materials science , population , sociology , composite material
Several studies have indicated that use of scales to age river carpsuckers Carpiodes carpio is difficult. Thus, an alternative body structure may reduce variability in aging this species and provide more accurate estimates of the growth history and age structure of river carpsucker populations. We compared the precision of age determinations and means of back‐calculated lengths at age of river carpsuckers between two readers and between the use of scales and dorsal fin ray sections from 172 individual fish collected in the Missouri River. Age agreement between the two readers was 71% for both scales and fin rays. Similarly, age agreement between scales and fin rays within readers was 68% and 72%. Precision of age determination by both readers declined after age‐5 for both structures. Generally, more annuli were detected on fin rays than scales as fish age exceeded 5 years. Means of back‐calculated lengths for ages 1–4 were significantly greater (P < 0.05) for fin rays than scales. Excluding ages lacking agreement between scales and fin rays had no significant influence (P > 0.05) on back‐calculated length‐at‐age estimates. We recommend the use of scales as the primary aging structure when growth and mortality dynamics of the young and most abundant age‐classes (e.g., age ≤6 years; total length ≤400 mm) are the primary interest. If estimates of annual mortality are to be extended to older age‐classes, fin rays should also be collected on river carpsuckers greater than 400 mm.