Relative condition factor: Le Cren's legacy for fisheries science

Aim: In this paper we present a scientometric analysis aimed at to assess and quantify the contribution of Le Cren’s condition factor and the main ideas advanced by ‘Le Cren, 1951’ to studies on the health of individuals or populations in aquatic environments. Specifically, we addressed the following questions: (i) what are the temporal and spatial citation trends of ‘Le Cren, 1951’?; (ii) Which journals cited ‘Le Cren, 1951’ most frequently?; (iii) In which types of aquatic environments and organisms have Le Cren’s condition factor been most commonly applied?; (iv) Which of the main applications addressed in ‘Le Cren, 1951’ have been most frequently used by fisheries scientists?; (v) Which of the methods (i.e., Quételet’s index or body mass index, Fulton’s condition factor, Le Cren’s condition factor, relative weight, residual index and scaled mass index) used to estimate condition factor identified in the papers that cited ‘Le Cren, 1951’ have been most frequently used? In addition, the main criticisms of the use of the relative condition factor are discussed. Methods: We carried out a scientometric analysis on the papers published from 1951 to December 2015 that cited Le Cren’s article. The papers were obtained from the Thomson Reuters database (ISI Web of Knowledge, apps.isiknowledge.com) in May 2016. Results: In total, 1128 papers were assessed. The number of citations increased significantly over time. Most citations occurred in two journals (Journal of Fish Biology and Journal of Applied Ichthyology). Most of papers were carried out in marine environments. In addition, we show that Le Cren’s paper has been cited mainly in articles that estimate the condition factor or the weight-length relationship of populations. Finally, we emphasize that the relative condition factor proposed by Le Cren in 1951 is still the main method used to estimate the body condition of an individual or population. Conclusions: Le Cren’s significant contribution to animal well-being is undeniable, and we emphasize that among the methods identified in the papers that cited ‘Le Cren, 1951’ that estimated body condition, the relative condition factor proposed by Le Cren in 1951 is still the most commonly used method.