Spatio-temporal variations in length-weight relationship and condition factor of two notopterids, Chitala chitala (Hamilton, 1822) and Notopterus notopterus (Pallas, 1769)

Length-weight relationship and condition factor of Chitala chitala (Hamilton, 1822) and Notopterus notopterus (Pallas, 1769) was studied from 439 samples of C. chitala collected from 14 locations and 368 samples of N. notopterus colleted from 19 locations in Indian rivers. The regression coefficient ranged from 2.24 (River Gomti) to 3.24 (River Son) in C. chitala and 2.34 (River Son) to 3.71 (River Krishna) in N. notopterus. Fulton’s condition factor and relative condition factor were found to be greater for N. notopterus than C. chitala in common sites of collection. Spatial variations indicated better biological behaviour for C. chitala in River Son and for N. notopterus in River Chambal. The results of the study form important baseline information for developing sustainable management and conservation measures.

Histomorphological study of the gut developmental pattern in early life history stages of featherback, Chitala chitala (Hamilton)

The present study was conducted to observe morphological and histological changes in the developing digestive system during the ontogeny of featherback, Chitala chitala (Hamilton), from hatching to 30 days post hatch (dph). Three significant stages were identified during digestive tract development in featherback: (1) endotrophic (0-8 dph), (2) endoexotrophic (8-12 dph), and (3) exotrophic (12-30 dph). At hatching, the mouth was closed and the digestive tract was a straight tube. At 8 dph, the mouth was opened and the appearance of the esophagus was observed. Between 6-8 dph, the primordial liver and exocrine pancreas were observed. Intestinal enterocyte activity was observed before stomach development. The esophageal goblet cells, teeth, and taste buds developed 2 days after the opening of the mouth, at the time of exogenous feeding. The development of the stomach, gastric glands, and pyloric caeca took place between the 7 and 12 dph. Except the increase in size and complexity of the structures, no noticeable changes were observed after 12 dphin C. chitala during the experiment. Our findings in the current work provide valuable information which might be useful for improving current larval rearing techniques of this promising new candidate species for freshwater aquaculture diversification.