Investigating otolith mass asymmetry in six benthic and pelagic fish species (Actinopterygii) from the Gulf of Tunis

Abstract

Otolith mass asymmetry can significantly affect the vestibular system functionalities; usually, the X values of mass asymmetry vary between −0.2 and + 0.2 (−0.2 < X < + 0.2). These values can change during a fish life and therefore they are not related to the fish total length. We collected a total of 404 fish specimens from the Gulf of Tunis, including three pelagic species: Sardina pilchardus (Walbaum, 1792) (74 otolith pairs), Trachurus mediterraneus (Steindachner, 1868) (66 otolith pairs), and Chelon auratus (Risso, 1810) (60 otolith pairs) and three benthic species: Gobius niger Linnaeus, 1758 (77 otolith pairs), Mullus barbatus Linnaeus, 1758 (60 otolith pairs), and Trachinus draco Linnaeus, 1758 (67 otolith pairs). The relation between the total length and the otolith mass asymmetry was first calculated and compared, and then was evaluated. The comparison of the otolith mass asymmetry between benthic and pelagic species showed a significant difference (P < 0.05), where the absolute mean value of X does not exceed the critical value (0.2) for all the studied species. No relation has been found between the magnitude of the otolith mass asymmetry and the length in both benthic and pelagic specimens. Environmental factors have an indirect effect on somatic growth and otolith accretion. The significant difference found in this study can be due to the difference between the benthic and pelagic environments.

Investigation of otolith asymmetry in Mulloidichthys flavolineatus and Parupeneus forsskali (Perciformes: Mullidae) from Egypt’s Hurghada fishing harbour on the Red Sea

“…This result agrees with that of Bouriga et al (2021) on Trachurus mediterraneaus collected from different sites on the Tunisian coasts of the Mediterranean Sea. Bouriga et al (2021) related such high values to the physiological condition of these species, their habitat, and environmental influences (abiotic and biotic), where ecological and anthropogenic pressures have a remarkable effect on the growth of otoliths (Grønkjaer 2016). The present results are also in agreement with those of Ben Labidi et al (2020b).…”

“…The extent of asymmetry in otolith dimensions and weight has been investigated in several fish species across a range of diverse environments from different countries. These include Acanthopagrus bifasciatus and A. latus from Iraqi marine waters (Abdulsamad et al 2020), Beryx splendens from the Arabian Sea coast of Oman (Albusaidi et al 2010), Liza Kluzingeri from the Persian Gulf (Sadigzadeh et al 2011), Carangoides caeruleopinnatus from Oman Gulf (Jawad et al 2012c), Merlangius merlangus from the Black Sea (Kontaş et al 2018) and Engraulis australis from the Hauraki Gulf, New Zealand (Ben Labidi et al 2020b), Boops boops, (Bouriga et al 2021), six benthic and pelagic fish species from Gulf of Tunis, (Khedher et al 2021), Diplodus vulgaris (Mejri et al), 2022a Pagellus erythrinus (Mejri et al 2022b), Liza aurata and Chelon ramada (Jawad & Adams 2021). In the Red Sea area, the asymmetry in the otolith dimensions was studied in Chlorurus sordidus and Hipposcarus harid (El Regal et al 2016).…”

The asymmetry in the sagitta of four mugilid species obtained from Köyceğiz Lagoon, Aegean Sea, Turkey

“…This result agrees with that of Bouriga et al . (2021) on Trachurus mediterraneus obtained from different sites in the Tunisian waters of the Mediterranean Sea. Bouriga et al .…”

“…Bouriga et al . (2021) linked such high values to the physiological condition of these species, their niches and ecological effects (abiotic and biotic), where environmental and anthropogenic pressures have a remarkable impact on the growth of otoliths (Grønkjær, 2016).…”

“…that ofBouriga et al (2021) on Trachurus mediterraneus obtained from different sites in the Tunisian waters of the Mediterranean Sea. Bouriga et al (2021) linked such high values to the physiological condition of these species, their niches and ecological effects (abiotic and biotic)…”