Intraspecific Population Variability in Goldstripe Ponyfish, Karalla daura Sampled along the Pakistan Coast Based on Geo-Morphometric Approach
Intraspecific Population Variability in Goldstripe Ponyfish, Karalla daura Sampled along the Pakistan Coast Based on Geo-Morphometric Approach
Imtiaz Kashani and Sher Khan Panhwar*
ABSTRACT
The use of geo-morphometric variables to discriminate fish populations is one of the appropriate, effective and widely adopted approaches to study population dynamics. To determine intrinsic population variability in goldstripe ponyfish, Karalla daura sampled from Keti Bunder, Karachi Fish Harbour, Hawks Bay and Pasni along the coastal belt of Pakistan. Size frequency distribution based on normal distribution demonstrates that individuals of 13 cm total length were common in all groups. Some fifteen morphometric and six geometric variables were used to develop Principal Component Analysis (PCA) that revealed (76%, 13.9% and 9.8%) variation deduced from first three components. The population sampled from Karachi fish harbors showed significant taxonomic variability. An eigenvalue 7.251 and canonical correlation 0.937 among four groups was appraised from PCI whereas Wilks’ Lambda test of function λ = 0.27 was significant at P <0.05. The highest variance percentage was the most correlated among the groups defined by total length, girth, 2nd dorsal fin, pectoral fin rays, eye dia, snout to extended gill cover and head length parameters. PC-II accounted for 13.9% of the variance that are more correlated with standard length, snout to eye tip, eye tip to first dorsal fin, base of 1st dorsal fin, last fin ray to tip of caudal, anal fin ray to pelvic fin ray, chin to snout and pelvic fin to pectoral fin. PC-III showed 9.8% variance with fork length, total weight, anal fin rays, last anal fin ray to 1st dorsal fin, tip of caudal fin to last anal fin ray, last anal fin ray to 1st anal fin, first pelvic fin to chin, eye to chin, 1st dorsal fin to last anal fin ray and last dorsal ray to last anal fin ray. among the groups. Whereas PC-IV has 0.3 % variance denoted by total weight, tip caudal fin to last anal fin ray. The PCA displayed a clear discrimination by sampling site, especially specimen from Karachi fish harbor were distinct from other location. Keti Bandar specimen was not dispersing as much as by geographical discrimination. Overall, results revealed that different topographies and environmental conditions causing significant variation in populations of Karalla daura. Therefore, it is assumed that this species has ability to adopt different ecosystem for survival despite acquiring adverse impact on phenotypic characteristics.
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