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The stream Balkhila is a glacier-fed and originates at higher altitudes from the Lal Mati glacier, flows through the famous Mandal valley of Garhwal Himalaya and finally merges with the Alaknanda River in Chamoli district of Uttarakhand. The present study aimed to assess the population structure, density and diversity of the periphyton community along with some detrimental ecological parameters in the glacier fed stream Balkhila for a period of two years on a monthly basis from November 2018 to October 2020. The stream Balkhila was represented by 17 periphytic genera belonging to 3 classes, namely, Bacillariophyceae, Chlorohyceae and Cyanophyceae. The class Bacillariophyceae was represented by 10 periphytic genera (Cymbella, Navicula, Fragilaria, Nitzschia, Ampohora, Diatoma, Synedra, Tabellaria, Cocconeis and Meridion), and Chlorophyceae (green algae) was represented by 6 algal genera (Chlorella, Ulothrix, Zygnema, Oedogomium, Spirogyra and Stigeoclonium). The class Myxophyceae was represented by a single genus (Phormidium). The maximum periphytic density (individuals/cm2) was found to be 316.7±7.1 x 103 in January, and the minimum density (12.5±3.5 x 103) was recorded in August. The SIMPLER test indicated 18.58% dissimilarity of periphytic communities between the two years of study. The Shannon–Wiener diversity index values were high (2.358 and 2.388) in December and January and minimum (0.2484 and 0.3534) in July and August during the first and second years of the study, respectively. Multivariate canonical correspondence analysis (CCA) suggested that most of the periphytic genera were closely associated with the winter season (December, January and February). The various ecological parameters of our study indicated that the Balkhila stream is a conducive habitat for periphyton communities.

Hydrachnidia is an important group of aquatic invertebrates. They play an important role in regulating other invertebrate populations, thus influencing the composition and functionality of river ecosystems. The present study aims to assess the habitat ecology, density and diversity of aquatic mites in the Khankra gad, Rudraprayag district for a period of two year on a monthly basis, from July 2018 to June 2020. The Khankra gad is a perennial spring-fed stream originating from the Bansoun peak in district-Rudraprayag of Garhwal Himalaya (800 m asl). A total of 2537 Hydrachnidia samples were collected, belonging to 6 families viz, Torrenticolidae, Sperchontidae, Feltriidae, Hygrobatidae, Lebertiidae and Aturidae. Sperchontidae, Torrenticolidae and Hygrobatidae were the common families recorded in both spots, whereas Feltriidae was recorded in Spot-1, Lebertiidae and Aturidae were recorded in Spot-2. The highest numbers (1842) of Hydrachnidia were collected from Spot-2. A total of 19 aquatic mite species were recorded in Spot-1 and 25 species in Spot-2 throughout the study period. Aquatic mites showed maximum density (177 units.m-2 in Spot-1 and 274units.m-2 in Spot-2) in December and minimum (11 units.m-2 in Spot-1 and 17 units.m-2 in Spot-2) in July. Various ecological parameters of our study indicated that Khankra gad is a good habitat for aquatic mites.

The ability to age fish accurately is essential in understanding the dynamics of fish population. Age and growth determination in Mastacembelus armatus was assessed by the scale method which was verified by the length-frequency distribution method. The scales were small, elongated and the focus was shifted slightly uppish from the centre. The fish length and scale radius relationship was found linear (Scale radius = 6.974 + 0.452 Fish length; r = 0.9746) and authenticated the age analysis. Back calculation method was used to find out the size of fish at annulus formation, which confirmed four age rings in M. armatus at the size of 14.07±0.92, 26.05±4.99, 37.96± 2.59 and 48.48±6.06 cm respectively. First two age rings were observed in the fish length group 30-40 cm, the third ring was observed in 40-50 cm and the fourth ring in 50-60 cm length group. The finding was dully validated by length-frequency distribution method. The growth annual increment (h) of M. armatus shows that the length increment was 14.07, 13.32, 11.91 and 10.52 cm during 1st, 2nd, 3rd and 4th year respectively. It shows that the fish grows continuously during its entire life period. The average growth (? h) was observed as 12.12 cm. annually. The assessment of age and growth rate of fish is a prerequisite to generate the information on recruitment, longevity and fluctuations in fishery caused by various year classes which is an important tool for rational exploitation of fish stock.

This paper reviews the isolation and identification of Aeromonas spp. through biochemical tests and molecular typing with special reference to their infection in human beings and future prospective of research related to human health.

Dolichos biflorus, a commonly used legume in Uttarakhand, produces alpha amylase enzyme for conversion of starch present in its cotyledons to glucose, so that this glucose can be further utilized for the life controlling processes, glycolysis and Kreb’s cycle. Yield of this á - amylase isolated from the germinating legume comes out to be 27.7 IUml-1. Maximal amylase production occurs at pH 6.1 at 45O C. The enzyme was purified two fold, first with ultra-filtration and then with Ion-exchange chromatography. Ultra-filtration revealed size of amylase to be between 10 kDa and 30 kDa, against larger sizes of other bacterial amylases. The pH and temperature optima for purified enzyme were 6.1 and 45OC respectively. The Km for starch came out to be 1.95 mgml-1. This finding of generating one more new and low-price source of á - amylase is a great advancement in biotechnology.

The  paper   deals  with  the  analysis  of  reproductive capacity of  Puntius  conchonius (Ham.-Buch.), an  important ornamental  fish  inhabiting   the   river  MandaI in  Garhwal  Himalaya. Study   is  based   on  73  mature female specimens  in  a  length   ranging  from  53  to  79  mm  were collected  from  river  Mandal. The  absolute  fecundity ranged   from  523.0  1±  100.3 ( fish  length  54.2  ± 1.I mm,  fish  weight 2782.5  ± 84.6  mg,  ovary  length   17.5 ± 1.2  mm and  ovary   weight   250.1 1 12.7 mg)  to  1366±  282  (fish  length   77.4±1.4  mm,  fish  wight 8408  ± 861 mg,  ovary length  26.2  ± 2.2  mm  and  ovary   weight  584.7 ± 112.7 mg).   Four   linear   relationships  were  observed  between fecundity  and  different  body  parameters  calculated by  the  method  of  least  squares.  Sex  ratio   of  fish  in  nature was  also  studied  monthly,  which  varied   from   1:1  (April) to  1:1.8 (July)   with  an  annual  average  I :1.17 (male: female,   X    0.013  which  is  insignificant) .Overall  it  was  found very   close  to  the  natural one.

The paper deals with maturation biology and spawning behaviour of a hillstream fish Botia dayi (Hora) collected from river Khoh in the foothills of Garhwal Himalaya, Uttaranchal. Seven maturity stages were determined for the fish. Based on GSI, Dobriyal index and availability of different maturity stages during months, it was inferred that the fish spawns during August- September as one time protracted spawner.

The paper deals with the study of epilithic periphyton and detritus standing stock in the river Eastern Nayar, which forms an important part of the food for macrozoobenthos and the fish, thus contributing greatly to the productivity of the stream.