Asymmetry in certain morphological characters of the carangid species Decapterus russelli, collected from the Lemah coastal area, on the northern part of Oman Sea

Abstract

Asymmetry analysis has been carried out for some bilateral characters of Decapterus russelli (Family: Carangidae) collected from Oman Sea. The results showed that postorbital length demonstrated the highest incidence of asymmetry among the characters studied. The lowest asymmetry value was for the number of pectoral fin rays. An increasing trend in the asymmetry value with fish length is also obtained for preorbital length, number of pectoral fins and number of lateral line scutes. A similar trend is also evident in the postorbital length and eye lens diameter of individuals with body sizes <160 mm. The possible causes of asymmetry in this species are herein discussed in relation to different pollutants and their presence in the area.

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

“…In the case of the otolith length, the present results also agree with those of Ben Labidi et al (2020a) in having an asymmetry in this biological feature of the otolith of M. flavolineatus and P. forsskali examined. The level of asymmetry of the otolith length obtained by Ben Labidi et al (2020a) was low, and they explained such low value because the developmental period of the otolith length may not be consistent with the presence of adverse environmental events (Jawad 2003). As previously mentioned by Helling et al (2003), the ostensible impact of bilateral asymmetry in fish otoliths is abnormal swimming activity and intrusion with correct sound localisation, resulting in the inability of the individuals to integrate with the environment in which they live (Lychakov & Rebane, 2005).…”

“…Relationships between fish health status and fluctuating asymmetry have been explored for several anatomical structures in fish. These include the number of gill rakers, pectoral fin rays, fish body proportions, eyespot area, and otolith size and shape (Jawad 2001(Jawad , 2003(Jawad , 2004Jawad et al 2012;Ben Labidi et al 2021;Ben Labidi et al 2020a,b). Measurement of the fluctuating asymmetry degree in the otoliths would be helpful for fisheries managers as it can provide an index of past individual and population suitability over time if time series of collections are available.…”

Bilateral fluctuation asymmetry of otoliths of Collichthys lucidus in different functional areas of Haizhou Bay

“…Fluctuating asymmetry (FA) refers to the slight random deviation of the left–right symmetry of organisms, which can reflect the impact of environmental pressure on organism populations (Clarke, 1992; Somarakis et al ., 1997). Many fish body parts and/or organs can be used to examine and evaluate FA ( e.g ., gill rake, number of pectoral fins, fish proportion, eye spot area) (Gonçalves et al ., 2002; Jawad, 2003, 2004). Studies have shown that the otolith FA of fish can serve as a sensitive characteristic for examining the impact of the environmental pressure and pollution status on fish populations (Abdulsamad et al ., 2020; Jawad, 2013).…”

FLUCTUATING ASYMMETRY REFLECT THE GROWTH OF HYBRID GROUPER Epinephelus fuscoguttatus AND Epinephelus polyphekadion

“…Fluctuating asymmetry results when a characters present on both sides of the body does not undergo identical development. It is also known that fluctuating asymmetry represent the degree of developmental sensitivity to environmental and genetic stress (Jawad et al, 2010).…”