No abstract

Schizothorax plagiostomus, commonly known as snow trout, is a popular food fish found in parts of Central Asia and the Indo‐Himalayan region. Despite such a broad range of distribution and potential financial value, it is a highly neglected cold‐water ichthyofauna. Furthermore, an alarming decline in Schizothoracine population has been reported in the recent past due to climate change and uncontrolled anthropogenic interference. In this study, the seasonal variations in ovarian architecture and development were examined in adult S. plagiostomus from Garhwal Himalayan region, Uttarakhand, India. Ovarian‐somatic index ranged from 16.86 ± 0.29 to 0.31 ± 0.56, with a maximal value in September and a minimal value in April. Ovarian histology revealed the abundance of primary growth oocytes in resting and preparatory stages; primary/secondary vitellogenic oocytes with numerous cortical alveoli were predominant in the developing stage of pre‐spawning ovaries; secondary/tertiary vitellogenic oocytes were conspicuous in actively spawning ovaries; and atretic follicles/oocytes were discernible during the regressing stage of spent ovaries. Scanning electron microscopy of mature ova (mean diameter 2.003 ± 0.01 mm) prominently showed the structure micropyle (mean diameter 12.93 ± 3.38 μm). Fecundity analyses suggested that September was the principal breeding season, whereas residual spawning occurred with fresh rain in late winter during February–March. Collectively, this is the first comprehensive qualitative and quantitative report of the seasonal variations in the ovarian development and function for S. plagiostomus. These data may provide valuable information towards the captive breeding programme as well as conservation and management for Schizothoracine fishes in normal and altered climatic conditions.

The aim of this study was to characterise physical and biochemical aspects of semen as well as to investigate the fine structure of spermatozoa of the Himalayan snowtrout Schizothorax plagiostomus Heckel, 1838 using scanning and transmission electron microscopy. The species breed twice in a year and semen was collected during both seasons, i.e. from 24 males in February and March, 2015 and from 30 males in September and October, 2015. Size of the fish ranged from 13.5 to 36 cm in February-March and 12.3 to 38 cm in September-October. The mean milt volume (ml), sperm density (×1010 ml-1) and spermatocrit (%) values were 2.25±1.26, 2.22±0.53 and 78.87± 8.25 in February-March and 2.12±1.25, 2.12±0.52 and 75.54±8.23 in September-October respectively. Biochemical parameters of seminal plasma viz., total protein (g dl-1), carbohydrates (mg dl-1) and total lipids were 0.312±0.05, 1.348±0.07 and 26.4±2.23 in February-March and 0.340±0.05, 1.34±0.1 and 26.4±3.19 in September-October respectively. Scanning and transmission electron microscopy studies of sperm revealed that the sperm was composed of an ovoid shaped head without acrosome, ellipsoidal midpiece with mitochondria and tail or flagellum. Flagellum had a typical 9+2 axoneme arrangement. The mean length (μm) of head, midpiece, flagella and total length of sperm were 1.82±0.24, 0.35±0.07, 20.18±0.79 and 22.3±3 respectively. For both the breeding seasons, sperm motility decreased significantly with time post-activation.

No abstract

The ecological diversity of insects and its predators like amphibians are important determinants in ecological balance.  A total of 1,222 prey items in 84 specimens were examined to contribute the understanding of the diets of three Duttaphrynus species, viz., himalayanus, melanostictus, and stomaticus from Uttarakhand, the western Himalaya, India.  Gut content analysis of three bufonids revealed acceptance of a wide range of terrestrial insects and other invertebrates as their food.  The index of relative importance indicated that the most important preys were Formicidae, Coleoptera and Orthoptera.  Duttaphrynus melanostictus had the broadest dietary niche breadth, followed by D. himalaynus and D. stomaticus.  The wide prey spectrum well indicates that these species are the generalist and opportunist invertebrate feeder.  Information pertaining to the food spectrum analysis contributes to understanding the ecological roles and used as a baseline data for future successful amphibian conservation and management programs in the Himalayan ecosystem.