Morphometrics, growth and length-weight relationaship of hilsa shad (Tenualosa ilisha) in the downstream Kotri Barrage Indus River, Pakistan

Morphological characteristics and length-weight relationship of hilsa shad (Tenualosa ilisha) from the downstream Kotri Barrage Indus River, Pakistan are examined. Total ۲۵ specimens (T. ilisha) were collected from August ۲۰۱۹ to September ۲۰۲۰ and found multiple dots in their bodies. These dots were varying in some extent; few of specimens have no dots while others were having ۱۲ dots. The dots consist of black color that appeared very first time in Pakistan and hvae no history in the past. The meristic are similar but morphometric characters; body length and weight were found different. The maximum and minimum weight and length were noted as ۲۵۴±۰.۷g and ۳۱±۰.۶g, ۲۱.۱±۰.۹cm and ۱۵.۵±۰.۸cm, respectively. Only three specimens were found without dots present in their body followed by four dots and nine dots, however, only two specimens categorized as two dots and twelve dots, five specimens with eight dots and seven specimens with single dot. The growth of fish was found higher in one dot specimens followed by four, eight and twelve dot specimens. Results also revealed that almost all specimens exhibited an isometric growth and the Length-weight relationship was significant with r۲ ≥۰.۹۵۴. The Hilsa (T. ilisha) is a migratory fish from sea to river for breeding and spawning purpose but, unfortunately illegal fishing, local demand, environmental change and habitat destruction cause Hilsa fish to decline continuously in the Indus River of Pakistan. Therefore, it is recommended that stock assessment with genomic studies of Hilsa Shad will be taken to distinguish the actual number of species present in the Indus River of Pakistan.