Bilateral asymmetry in the mass and size of otolith of two cichlid species collected from Lake Ahémé and Porto-Novo Lagoon (Bénin, West Africa)

Abstract

Asimetría bilateral en la masa y el tamaño de otolitos de dos especies de cíclidos capturados en el lago Ahémé y la laguna de Porto Novo (Benín, África Occidental) Se estudia la asimetría de la masa del otolito sacular en dos especies de peces cíclidos Sarotherodon melanotheron y Coptodon guineensis recolectadas del lago Ahémé y la laguna Porto-Novo, Benín, África occidental. La longitud y el ancho de los otolitos de especímenes adultos de ambas especies se usaron para calcular la asimetría fluctuante en estos dos caracteres. Los resultados muestran que el nivel de asimetría del ancho del otolito es el más importante. La posible causa de la asimetría en estas especies se ha discutido en relación con diferentes contaminantes en el área. Nuestros datos no muestran diferencias significativas, aunque varios estudios demostraron una asimetría más alta en individuos más grandes (de más edad). Saccular otolith mass asymmetry is studied in two cichlid fish species Sarotherodon melanotheron and Coptodon guineensis collected from Lake Ahémé and Porto-Novo Lagoon, Bénin, West Africa. The length and width of otoliths from adult specimens of both species were used to calculate the fluctuating asymmetry in these two characters. The results show that the level of asymmetry of the otolith width is the most important. The possible cause of the asymmetry in these species has been discussed in relation to different pollutants in the area. Our data show no significant difference, although several studies proved a higher asymmetry in larger (older) individuals.

Otolith fluctuating asymmetry inBoops boops(Actinopterygii, Sparidae) from two marine stations (Bizerte and Kelibia) in Tunisian waters

“…Jawad (2012) mentioned that the level of asymmetry in the otolith width is the highest among the length and width values of Lutjanus bengalensis collected from the Muscat coast on the sea of Oman, with a trend towards increasing asymmetry in the length and width as the fish increases in length, adding that this asymmetry is attributed to the various pollutants present in the area. Similarly Jawad (2012) and Jawad et al (2012a) in Sardinella sindensis and Sillago sihama collected from the Persian Gulf near Bandar Abbas and Jawad et al (2020) in Sarotherodon melanotheron and Coptodon guineensis examined from Lake Ahémé and Porto-Novo Lagoon, Bénin, found the same results, except that a trend of increase in the value of asymmetry with fish length has been observed in the otolith width only. However, Al-Busaidi et al (2017) reported that both the length and width measurements of the otolith estimated from L. ehrenbergii in the Sea of Oman at Muscat City are good indicators for fish length and there is symmetry between the left and right otoliths.…”

“…During the last decades, study of the morphological characteristics of otoliths, in particular their shape, length, width, area, thickness and weight, has been used to test both genetic and environmental stressors and as a bioindicator to test the differentiation of populations and the variance in stock discrimination studies using Elliptical Fourier analysis (EFA) (Valentine et al, 1973;Campana & Casselman, 1993;Begg & Waldman, 1999;Torres et al, 2000;Smith et al, 2002;Panfili et al, 2005;Turan, 2006;Jawad et al, 2010Jawad et al, , 2011Jawad et al, , 2012aJawad et al, , 2012bJawad et al, , 2012cJawad et al, , 2016Jawad et al, , 2020Vignon & Morat, 2010;Cañás et al, 2012;Jawad, 2012Jawad, , 2013Lord et al, 2012;Treinen-Crespo et al, 2012;Mahe et al, 2014;Trojette et al, 2014Trojette et al, , 2015Abu El-Regal et al, 2016;Brophy et al, 2016;Hüssy et al, 2016;Rebaya et al, 2016Rebaya et al, , 2017Al-Busaidi et al, 2017;Fatnassi et al, 2017;Ider et al, 2017;Khedher et al, 2017;Rodgveller et al, 2017;Chakour & Elouizgani, 2018;Khemiri et al, 2018;Kontaş et al, 2018;Mejri et al, 2018;Wang et al, 2018;…”

“…During the last decades, study of the morphological characteristics of otoliths, in particular their shape, length, width, area, thickness and weight, has been used to test both genetic and environmental stressors and as a bioindicator to test the differentiation of populations and the variance in stock discrimination studies using Elliptical Fourier analysis (EFA) (Valentine et al ., 1973; Campana & Casselman, 1993; Begg & Waldman, 1999; Torres et al ., 2000; Smith et al ., 2002; Panfili et al ., 2005; Turan, 2006; Jawad et al ., 2010, 2011, 2012 a , 2012 b , 2012 c , 2016, 2020; Vignon & Morat, 2010; Cañás et al ., 2012; Jawad, 2012, 2013; Lord et al ., 2012; Treinen-Crespo et al ., 2012; Mahe et al ., 2014; Trojette et al ., 2014, 2015; Abu El-Regal et al ., 2016; Brophy et al ., 2016; Hüssy et al ., 2016; Rebaya et al ., 2016, 2017; Al-Busaidi et al ., 2017; Fatnassi et al ., 2017; Ider et al ., 2017; Khedher et al ., 2017; Rodgveller et al ., 2017; Chakour & Elouizgani, 2018; Khemiri et al ., 2018; Kontaş et al ., 2018; Mejri et al ., 2018; 2020; Wang et al ., 2018; Ben Mohamed et al ., 2019; Fashandi et al ., 2019; Jmil et al ., 2019; Mahé et al ., 2019; Puentes et al ., 2019; Osman et al ., 2020). Indeed, these studies have shown that the otolith shape is species-specific (Sadighzadeh et al ., 2014) and that variability in the otolith shape, structure and development is influenced by ontogenetic, genetic and environmental factors (Campana & Casselman, 1993; Cardinale et al ., 2004; Vignon & Morat, 2010; Vignon, 2015; Hüssy et al ., 2016; Ider et al ., 2017; Fashandi et al ., 2019), as well as by sex, growth, maturity and pattern of fishery exploitation (Begg & Brown, 2000), or by individual characteristics, e.g.…”

“…Indeed, these studies have shown that the otolith shape is species-specific (Sadighzadeh et al ., 2014) and that variability in the otolith shape, structure and development is influenced by ontogenetic, genetic and environmental factors (Campana & Casselman, 1993; Cardinale et al ., 2004; Vignon & Morat, 2010; Vignon, 2015; Hüssy et al ., 2016; Ider et al ., 2017; Fashandi et al ., 2019), as well as by sex, growth, maturity and pattern of fishery exploitation (Begg & Brown, 2000), or by individual characteristics, e.g. the individual genotype (Jawad et al ., 2020) or the physiological state (Campana & Neilson, 1985). But the possible cause of intra-individual variation, particularly the asymmetry in shape between the right and left otoliths, has been poorly studied (Mille et al ., 2015).…”

Stock discrimination of the bogue, Boops boops (Actinopterygii: Perciformes: Sparidae), from two Tunisian marine stations using the otolith shape

“…Besides, the anatomy of the otolith has been shown to play an important role in discriminating the stock based on the life traits of individuals with the evolution of the habitat (Arai et al 2007). Studies of morphological variability in the otolith shape, structure, and development have shown that the otolith shape is species-specific and is influenced by ontogenetic, genetic, and environmental factors (Fashandi et al 2019), as well as by sex, growth, maturity, and pattern of fishery exploitation (Begg and Brown 2000), or by individual characteristics, e.g., the individual genotype (Jawad et al 2020) or the physiological state (Campana and Neilson 1985). But the possible cause of the intra-individual variation, particularly the asymmetry in shape between the right and left otoliths, has been poorly studied (Mille et al 2015).…”