Fish size effect on sagittal otolith outer shape variability in round gobyNeogobius melanostomus(Pallas 1814)

Abstract

Round goby Neogobius melanostomus (Pallas 1814) has become a significant component in the diet of piscivorous fish from the Pomeranian Bay (Bornholm Basin, Baltic Sea). Proper identification of fish species in the diet of predators is significant in biological studies of fish and other aquatic animal species, and, with regard to N. melanostomus, it is important to the knowledge of trophic web structures in areas this species has invaded. A total of 142 individuals of N. melanostomus, measuring 16-174 mm standard length, were examined. Seventy-two fishes were caught during monitoring surveys in fishing grounds, whereas 70 were found in the stomachs of European perch Perca fluviatilis, pike-perch Sander lucioperca and Baltic cod Gadus morhua. The objective of the present study was to analyse the sagittal otoliths to identify variations in outer shape with increases in fish length; expand and correct descriptions of the sagitta, lapillus and asteriscus otoliths; and evaluate the relationships among otolith dimensions and fish standard length. The otoliths were described morphologically. The analysis of the outer shape of sagittal otoliths using Fourier analysis and multivariate statistics exhibited great phenotypic variability that was associated with fish length, including within pairs in individuals and/or among individuals in length classes. In addition, the asterisci and lapilli of N. melanostomus from selected specimens, which were described for the first time with regard to fish length, were found to be less variable compared to sagittal otoliths. This study presents the first analysis of intrapopulation phenotypic plasticity of N. melanostomus sagittal otolith morphology as it is linked to fish size.

Discrimination of Diplodus vulgaris (Actinopterygii, Sparidae) stock from two Tunisian lagoons using otolith shape analysis

“…Therefore, geographic variation in otolith shapes may result from population differences (Stransky, 2005). Recent studies have shown that the otolith shape can vary within and among species due to the combined effects of ontogenetic, genetic and environmental factors, such as temperature, salinity or light regime and food availability (quality and quantity) (Hüssy, 2008; Capoccioni et al ., 2011; Berg et al ., 2018; Ferri et al ., 2018; Ben Labidi et al ., 2020 a ; Więcaszek et al ., 2020) or by sex, growth, maturity and pattern of fishery exploitation (Begg & Brown, 2000), or by individual genotype (Berg et al ., 2018; Jawad et al ., 2020) or the physiological state (Campana & Neilson, 1985), and the separation of populations in both time and space (Lombarte & Lleonart, 1993). In addition, the microstructural increments within otoliths have been used to elucidate the link between sex-change and growth history (McCormick et al ., 2010), since once the deposition of increments has been appropriately validated, the width of increments can be used as a proxy for somatic growth (Campana, 2001).…”

Stock Discrimination of Northern Pike Esox lucius L., 1758 Inhabiting Lakes Simenlik and Ladik (Samsun-Turkey) Using Otolith Biometry and Shape Analysis

“…Relationships between fish size and otolith morphometrics are a baseline for prey-predator studies. Analyzing otoliths retrieved from the stomachs or faeces of piscivorous predators can provide information on the type, size, mass, and energy content of their fish prey (Więcaszek et al 2020). E. lucius is an important recreational, predator, and top-level piscivore.…”

First documentation of the otoliths of the species of Gouania (Teleostei: Gobiesocidae) in the Mediterranean Sea

“…As the sample available for each species was small (and the body sizes of specimens varied within and among groups), no conclusions could be drawn with regard to within‐species variability of the otoliths such as sexual dimorphism (Teimori et al ., 2020; Vaux et al ., 2019), ontogenetic variation (Vignon, 2012; Więcaszek et al ., 2020) or asymmetry between right and left otoliths (Lord et al ., 2012; Lychakov et al ., 2008; Panfili et al ., 2005). Nonetheless, some preliminary remarks can be made based on the comparison between otolith groups.…”