Otolith morphometry provides length and weight predictions and insights about capture sites of Prochilodus lineatus (Characiformes: Prochilodontidae)

Abstract

Here we choose the sábalo Prochilodus lineatus, to answer the following questions: How the otolith length and weight are correlated to fish measurements (length and weight)? How reliable are the otoliths measurements to predict the length and age of P. lineatus? Finally, we propose predictive equations of the length and weight of the fish using length and weight of the otolith. The otoliths were sampled from individuals collected in the Upper Paraná River floodplain during 2012 and 2013 years. The relationships among the otolith measurements and both length and weight of the fish were performed using linear regressions. To test whether the length and weight of the otolith differ between the sampled sites, Variance Analysis was performed. Finally, we made analysis of Kruskal-Wallis to verify if the measurements obtained through the otoliths could be used to distinguish the age of the fish. We demonstrate that the length and weight of the otolith are good proxies to predict the length and weight of the fish. Although some ages were statistically different, this result does not support the idea that the age of the fish can be accurately inferred only using otolith measures.

Mass‐effect: Understanding the relationship between age and otolith weight in fishes

“…Fossen et al (2003), calculate the Spearman's range correlation as an equivalent to the Pearson's correlation coefficient (r), if n ≥ 90, r = ρ (Lajeunesse, 2013). In particular cases, such as Santana et al (2018), the otolith weight was included as a result of parallel analysis and enough information to calculate r. For Fletcher (1991); Francis and Smith (1995); Campana and Fowler (2012); Bermejo (2014) and Mu et al (2018), the r-values were retro-calculated through extrapolation by using ImageJ/ Fiji 1.5f (NIH, Bethesda, MD, Schneider et al, 2012). This procedure allows to visually approximate the correlation coefficient from the model outputs.…”

“…Currently, studies in continental waters have folded (Lozano et al, 2014). In some freshwater species such as Prochilodus lineatus, the sagitta otolith is reduced and not used for age and growth studies, while the asteriscus and lapillus otoliths are more developed (Santana et al, 2018). Our database includes published research that used the sagitta otolith on their analyses, except for the study by Santana et al (2018) who used the lapillus otolith.…”

“…In some freshwater species such as Prochilodus lineatus, the sagitta otolith is reduced and not used for age and growth studies, while the asteriscus and lapillus otoliths are more developed (Santana et al, 2018). Our database includes published research that used the sagitta otolith on their analyses, except for the study by Santana et al (2018) who used the lapillus otolith. Fletcher (1991) highlighted that the overlap in otolith weight by age should be minimal to validate its use for age estimation.…”

“…Our database includes published research that used the sagitta otolith on their analyses, except for the study by Santana et al. (2018) who used the lapillus otolith.…”

“…In particular cases, such as Santana et al. (2018), the otolith weight was included as a result of parallel analysis and enough information to calculate r . For Fletcher (1991); Francis and Smith (1995); Campana and Fowler (2012); Bermejo (2014) and Mu et al.…”