Age determination in common carp Cyprinus carpio: history, relative utility of ageing structures, precision and accuracy

Abstract

The common carp Cyprinus carpio is one of the most widely-distributed freshwater fishes in the world. Due to its value for conservation and fisheries in several native/translocated areas of distribution and its detrimental effects on the aquatic ecosystem in most invasive areas, robust age-based population dynamics models are required for successful management of this species. The present study provides a global review of age determination in carp, including a historical account of ageing methods, an assessment of the relative utility of ageing structures, and an evaluation of precision and accuracy (i.e. validation) of age estimates. Historically, scales were by far the most widely-employed structure, followed by the operculum, otolith, dorsal spine, vertebra and fin ray. However, in countries where carp is categorised as 'high risk' of impact, use of alternative structures to the scale was predominant. Causal criteria analysis showed scales and opercula to provide inconsistent evidence for successful annulus identification/counting, whereas consistent evidence was found for otoliths, dorsal spines, vertebrae and (pectoral) fin rays. Precision was always above reference thresholds for scales, whereas for otoliths, dorsal spines and fin rays was in several cases below. Accuracy was addressed sporadically and mostly in high-risk countries. It is suggested that dorsal spines or pectoral fin rays should be used in lieu of scales as non-lethal ageing structures, and otoliths (or vertebrae, pending more research) otherwise, and that validation should always be attempted as part of the set-up of more appropriate ageing protocols and use of correct terminology.

Population responses of common carp Cyprinus carpio to floods and droughts in the Pampean wetlands of South America

“…Asteriscus otoliths (Vilizzi 2018) were embedded in clear epoxy resin blocks with their nuclei aligned and transversely sectioned along the dorso-ventral plane through the primordia using a cutting saw. Otolith sections (0.4 mm) were mounted on microscope slides and analyzed under a microscope using transmitted light by two individual readers without knowledge of the date of capture or fish length.…”

Daily age determination and growth rates of freshwater fish throughout a regulated lotic system of the Murray‐Darling Basin Australia

“…For common carp, the lapilli rather than sagittae were used (Vilizzi, 2018;Vilizzi & Walker, 1999). For common carp, the lapilli rather than sagittae were used (Vilizzi, 2018;Vilizzi & Walker, 1999).…”

“…To examine and enumerate daily otolith growth increments, a sagittal otolith (sagittae) was extracted and mounted on a microscope slide using crystalbond mounting adhesive (Structure Probe Inc., West Chester, PA, USA). For common carp, the lapilli rather than sagittae were used (Vilizzi, 2018;Vilizzi & Walker, 1999). Otoliths were polished by hand to the core, either longitudinally from the proximal surface or from the dorsal and ventral margins for larger specimens (i.e.…”

Otolith shape analysis and daily increment validation during ontogeny of larval and juvenile European chub Squalius cephalus

“…Research on the early life history of fishes is fundamental to understand population dynamics (Bergenius et al ., ) and reliable estimates of age and growth are required to assess survival and recruitment success (Campana & Thorrold, ; Jones, ; Begg et al ., ). Age can be estimated from several calcified structures of the fish (also called hard parts) such as scales, opercula, vertebrae, spines, fin rays and otoliths (Sikstrom, ; Casselman, ; Khan & Khan, ; Vilizzi, ). The otoliths are usually the first calcified structures to develop in fish larvae and some of the three pairs (sagitta, lapillus and asteriscus) are already visible before hatching (Brothers, ).…”