Assessment of morphological variation between stocks of bluefish, Pomatomus saltatrix (Actinopterygii, Perciformes, Pomatomidae), in the Aegean Sea, Black Sea, and Sea of Marmara

Abstract

The population structure of the bluefish, Pomatomus saltatrix (Linnaeus, 1766), in Turkish waters is scarcely described in the literature. To identify any distinct population units of bluefish, and reaffirm the findings of a previous study, four areas were selected: the Aegean Sea, western Black Sea, eastern Black Sea, and the Sea of Marmara. In this study, truss network morphometrics, meristics, and otolith shape analyses were successfully applied for different population identification of the bluefish. Multivariate analysis of variance (MANOVA) revealed no differences for truss network morphometrics, meristic, and otolith shape characters between males and females. Hence, both sexes were combined for the discriminant function (DFA) and the Principal Component Analysis (PCA). Using univariate ANOVA based on the stepwise method revealed a highly significant difference among different locations for each truss-morphometrics and otolith shape characters. Furthermore, six out of seven meristic characters also showed significant differences between different areas. Based on PCA, 25 out of 27 truss-morphometric characters had a loading value above 0.70, which was considered significant in this study. The results of DFA show clear patterns of truss-morphometric character variations, forming four distinct clusters that were well separated from each other, indicating the existence of four morphologically differentiated populations of the bluefish. The proportion of the correctly classified Aegean Sea, western Black Sea, and eastern Black Sea bluefish samples to their original groups were 100%, demonstrating clear separation of these stocks from each other. Whereas up to 5% of the total samples of the Sea of Marmara were incorrectly classified, assigning to the eastern Black Sea. These findings were supported by meristic and otolith shape characters that also indicated four morphologically differentiated populations of the bluefish. However, their overall proportion of correct classification was relatively lower than the truss-morphometric traits method. The findings suggest the requirement of strategic assessment and management of each bluefish stock separately to use them sustainably in the future.

Morphometric variation of Spicara flexuosum Rafinesque, 1810 (Teleostei: Sparidae) inhabiting the Sea of Marmara, the Aegean and the Mediterranean Coast of Türkiye

“…water temperature, current, also chemical characteristics, e.g. O 2 , water clarity (Shuai et al 2018) (Bal et al 2021), African freshwater fish (Turan et al 2005), and European anchovy (Khan et al 2022).…”

“…Overall, fish functional morphological traits were understood to be influenced by physical properties of water, such as flow and temperature within fresh water (Chapman et al 2015, Shuai et al 2018) and salinity differences among marine water habitat (Winans 1984, Vidalis et al 1997, Erdoğan et al 2009). The spatial distribution of fish species was previously investigated in different fish species populations in three different seas in Turkish coastal waters, and most of the studies reported that species from the Black Sea populations were separated from the Marmara, Aegean and the Mediterranean Sea (Turan et al 2006, Yedier & Bostancı 2021, Bal et al 2021.…”

“…Morphometric analyses were previously available and used for inter-and intra-specific differentiation of fish species in the literature, such as Pomatomus saltatrix from the Aegean, Black Sea, and the Mediterranean (Turan et al 2006) and the Sea of Marmara (Bal et al 2021) and the three Scorpena species from the Aegean, Black, Mediterranean and the Marmara Sea (Yedier & Bostancı 2021). Different metric and meristic characters and their relative distributions were also observed for phylogenetic determination and taxonomy of freshwater fishes for Luciobarbus barbulus in the Persian Gulf Basin (Khaefi et al 2017, Khaefi et al 2018, three Gourami species in Indonesia (Perdana et al 2021) and some marine fish species, such as Chromis chromis (Aydın & Öztürk 2021) Sciaena umbra (Aydın & Bodur 2021) in the Black Sea.…”

Morphological variations of an invasive cyprinid fish (Carassius gibelio) in lentic and lotic environments inferred from the body, otolith, and scale shapes

“…The morphometrics data of otolith and scale were standardised for the standard length of C. gibelio to remove the effect of body size using the allometric equation (Lombarte & Lleonart, 1993) , where V trans is the transformed variable, V is the non‐transformed variable, SL is the standard length of each fish, and SL m is the overall (arithmetic) mean standard length of all fish, and b is the slope of the regression of log V on logSL. The modified morphometrics data of otolith and scale were tested for normality and outliers (Bal et al, 2021). Outliers were removed before the subsequent analyses.…”

Using otolith and body shape to discriminate between stocks of European anchovy (Engraulidae: Engraulis encrasicolus) from the Aegean, Marmara and Black Seas

“…The stock structure can be identified through otolith shape and microchemistry, morphometrics and meristic variables, life‐history parameters, parasites and parentage‐based tagging, and genetic approaches (Begg et al ., 1999; Bose et al ., 2017; Neves et al ., 2020). Several studies recommend the use of more than a single stock identification method for assessing phenotypic heterogeneity between subpopulations and achieving sound conclusions (Bal et al ., 2021; Turan et al ., 2006; Waldman et al ., 1988).…”