Bias, precision and validation of ageing 0+ European barbel Barbus barbus (L.) from their otoliths

Abstract

The European barbel Barbus barbus L. is considered a ‘flag’ species for river conservation and sport fishing, but it is increasingly threatened in its native range of distribution. To provide accurate age estimates during early life for appropriate management and conservation measures, the bias and precision of otolith (daily) micro-increment counts were evaluated and age determinations validated on laboratory-reared embryos and larvae. Out of the three pairs of otoliths, the lapillus and sagitta provided reliable age estimates for free embryos and larvae up to 17 days of (known) age post-fertilisation, with first micro-increment formation occurring five days postfertilisation. On the other hand, micro-increments on asterisci formed only 16–17 days post-fertilisation. There was agreement in microincrement counts based on lapilli and sagittae, but not between interpreters, indicating that despite consistency between the two pairs of otoliths extensive training and experience are required for reliable age interpretation. The ability to estimate the ages of 0+ B. barbus from their otoliths will contribute to a better understanding of growth rates from both hatchery-stocked and native/introduced cohorts.

An accurate tool for ageing Two‐spined Blackfish for use in determining timing of spawning in upland streams in the Brindabella ranges, ACT, Australia

“…The otolith microstructure of juvenile Two-spined Blackfish showed deposition of concentric rings around a central core/s that is consistent with microstructure of the majority of teleosts (Stevenson & Campana 1992) including those from Australia (Hale & Swearer 2008;Vilizzi & Copp 2013) and more specifically those of Percichthyidae in the Murray-Darling Basin (Humphries 2005;Koehn & Harrington 2006;Brown & Wooden 2007). Of the three pairs of otoliths in Two-spined Blackfish, only the lapilli and sagittae were useful for ageing juveniles using techniques described in this study, with the asterisci unsuitable for microstructure examination as is common in other studies (see Secor & Dean 1992).…”

Saccular Otolith Morphometry of Aksu Goby, Ponticola turani (Kovačić & Engin, 2008)

“…Balıklarda yaş tayini (Arslan & Yazıcı, 2020;Bostancı vd., 2009;Vilizzi & Copp, 2013;Yazıcı vd., 2014), büyüme parametrelerinin tahmin edilmesi (Santic vd., 2013;Yazıcı vd., 2015), stok veya populasyon ayrımı (Canas vd., 2012;Özpiçak vd., 2018), tür tanımlaması (Assis, 2005;Bani vd, 2013;Bostancı vd., 2015) ve ekomorfolojik analizler (Tuset vd., 2010;Volpedo & Echeverria, 2003) gibi birçok alanda otolitlerden yararlanılmaktadır.…”

There and back again: Spatial and temporal variation in the recruitment dynamics of an amphidromous fish

“…While the formation of rings is influenced by physical processes, a critical step in the accurate aging of fish is the validation of rings forming in a regular temporal pattern. This has been done for a considerable number of species (Taubert and Coble 1977, Fowler and Doherty 1992, Stewart et al 1995, Newman et al 1996, Vigliola 1997, Cappo et al 2000, Vilizzi and Copp 2013, and for the focal species of this thesis, Galaxias maculatus (McDowall et al 1994).…”