Assessment Of Morphometric Components Of The Grey Mullet (Mugil Cephalus) In Uta Ewa River Estuary, Southeastern Nigeria

Abstract

The morphological diversity and growth patterns of fish populations provide crucial insights into their ecology, reproductive strategies, and responses to environmental changes. This study aimed to investigate the variability in morphometric traits of Grey Mullet (Mugil cephalus) from Utaewa Beach, Imo River, Akwa Ibom State. The study involved the monthly measurement of 17 morphometric traits on a total of 290 samples of M. cephalus for six months from May to October 2023. The study applied descriptive statistics, T-test for sex difference, correlation analysis for trait-length relationships, and principal component analysis. The findings revealed a wide range of variability across all measured morphometric traits. Notably, body weight (BW) varied from 7.9g to 273.2g, with a mean of 65.2g. Total length (TL) measurements ranged from 9.9cm to 31.1cm, indicating significant diversity within the population. Also, statistical analysis unveiled significant sexual dimorphism across most traits, with females generally larger than males (e.g., body weight in females: mean = 65.2g, males: significantly lower, p < 0.05). Strong correlations between fish length and morphometric traits such as the distance from the snout to the dorsal fins (DDF1 and DDF2; r > 0.9) were observed, indicating proportional growth patterns. Principal component analysis showed that the first component accounted for 74.13% of the variance, highlighting key morphometric traits contributing to overall variability. These findings underline the necessity for sex-specific management strategies in Grey Mullet fisheries to support sustainable exploitation and conservation, advocating for further research into the environmental and genetic determinants of morphometric diversity.