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On the back‐calculation of fish lengths; modifications and extensions to the Fraser‐Lee equation
Author(s) -
Duncan K. W.
Publication year - 1980
Publication title -
journal of fish biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.672
H-Index - 115
eISSN - 1095-8649
pISSN - 0022-1112
DOI - 10.1111/j.1095-8649.1980.tb03751.x
Subject(s) - perch , fish <actinopterygii> , algebraic number , basis (linear algebra) , biology , regression , constant (computer programming) , algebraic equation , mathematics , geometry , mathematical analysis , statistics , fishery , computer science , physics , quantum mechanics , nonlinear system , programming language
The basis of the widely used Fraser‐Lee equation for back‐calculating lengths is discussed and a new algebraic method of calculating the constant is given. This algebraic method gave satisfactory results for the back‐calculation of European perch ( Perca fluviatilis L.) lengths in Lake Mahinerangi, New Zealand. Errors in back‐calculation are much higher than regression techniques would suggest. Causes of the Rosa Lee phenomenon are discussed and methods are given for detecting it and compensating for it using a computer program, BACKCALC.