Premium
Comparison of Methods for Estimating Age, Growth, and Related Population Characteristics of White Crappies
Author(s) -
Hammers Brad E.,
Miranda L. Esteban
Publication year - 1991
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(1991)011<0492:comfea>2.3.co;2
Subject(s) - otolith , population , annulus (botany) , statistics , fish <actinopterygii> , biology , mathematics , demography , fishery , botany , sociology
Estimates of age and growth of the white crappie Pomoxis annularis in Mississippi were based on 2,162 sets of scales and otoliths and on 4,196 length samples. The maximum ages identified were 8 years from otoliths, 7 from scales, and 6 from length‐frequency analysis with the computer program MIX. Ages assigned to scales and otoliths by two readers agreed 79 and 91% of the time, respectively. Ages assigned to scales and otoliths taken from the same fish agreed only 74% of the time. Ages determined from scale and otolith samples obtained from known‐age white crappies disagreed because the scales had developed a false annulus. At age 1, but not at older ages, estimates of growth derived from otoliths were significantly ( P ≤ 0.05) higher than those derived from scales. Growth estimated from length‐frequency modes was generally slower than that estimated from scales or otoliths, but it was significantly slower only at age 1. Unless length samples are obtained during the period of annulus formation, length modes probably will incorrectly estimate length at age. Despite discrepancies among age and growth estimates provided by the three methods, population statistics derived from estimates the methods provided were similar. We suggest that otoliths be used to estimate age and growth of white crappies. Alternatively, if the application allows for reduced accuracy, or if releasing fish alive is a major concern, the scale and length‐frequency methods can provide age and growth data that yield population statistics sufficiently similar to those produced by otoliths to be useful in assessing fisheries.