• Prakash Nautiyal

      Articles written in Proceedings – Animal Sciences

    • Natural history of the Garhwal himalayan mahseerTor putitora (Hamilton) II. Breeding biology

      Prakash Nautiyal

      More Details Abstract Fulltext PDF

      The fish matured only after attaining an average length of 700 to 770 mm. The period between July to September was established to be its spawning season. Observations on the Gonado-Somatic Index (GSI) and relative condition factor confirmed this observation. The variation in the sex-ratio during the spawning season was considered to be a remarkable adaptation towards low fecundity. The paper also comments on the problems of the Garhwal Himalayan mahseer and precautionary methods awaiting implementation in this region.

    • Studies on riverine ecology of torrential waters in the uplands of the Garhwal region II. Seasonal fluctuations in diatom density

      Prakash Nautiyal

      More Details Abstract Fulltext PDF

      Seasonal fluctuations along with certain physico-chemical parameters were recorded for two hillstreams, the Alaknanda (snow-fed) and the Nayar (spring-fed). In the former, the water temperature range of 9–14°C is considered optimum for the growth of diatoms, compared to 12–21°C in the Nayar. In both hillstreams diatoms achieved their maxima during January, when the water temperature is the lowest. Sudden influx of rain water carrying enormous silt during monsoon is responsible for the decline in density. The water temperature and current, especially the latter is thus a detrimental factor. The interesting feature of the study is, the relatively higher percentage of diatoms in the Nayar than in the Alaknanda, obviously to be attributed to the warm waters in the former.

    • Discharge-time method. A new technique for sampling plankton in fluvial systems, with a note on the modified plankton sampling device

      Prakash Nautiyal A S Saklani H R Singh

      More Details Abstract Fulltext PDF

      A technique to sample plankton efficiently in the fluvial systems is being propounded along with a note on the need and design of the plankton sampling device suited to torrential reaches. The technique, christened as discharge-time method, has certain advantages. The requirements are minimum (detachable bucket of the conical plankton net with bolting silk cloth of required mesh size) and the efforts are nominal. In order to sample plankton the device has to be dipped into the river with its open end facing the current, for a pre-calculated period of time. The formula, ‘t’ seconds=x/4v was computed to calculate the time for which the device should remain submerged. It is thus, an efficient and time saving technique for large volumes can be filtered within seconds. The validity of this method has been assessed by employing ‘t’ test.

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