Wyniki wyszukiwania - BazTech

Ograniczanie wyników

Znaleziono wyników: 2

Liczba wyników na stronie

Wyniki wyszukiwania

Wyszukiwano:
w słowach kluczowych: fish diversity

Sortuj według:

Ogranicz wyniki do:

Impact of Jute Retting on Native Fish Diversity and Aquatic Health of Roadside Transitory Water Bodies: an Assessment in Eastern India

Ghosh D., Biswas J. K.

Journal of Ecological Engineering

2015

Vol. 16, nr 4

14--21

Roadside transitory water bodies being manmade depressions have a great ecological and socio-economic importance from years. The effects of agricultural runoffs, jute retting, macro-phytes infestations and inadequate rainfall in changed climate often degrade transitory water bodies’ environment while the biodiversity have impacted severely because of population pressure, over exploitation and indiscriminate use of fine meshed fishing gears as a whole. Physico-chemical and biological analysis with fish species composition, relative abundance, diversity indices like species richness, evenness and Shannon-Wiener index were carried out for pre-, during and post-jute retting season and for year mean as a whole to assess impact of jute retting on the roadside transitory water body’s environmental health and indigenous fish diversity at Sahebnagar village in Nadia District, India. All the physico-chemical parameters barring biochemical oxygen demand and water transparency remained more or less same or marginally got little changed during those three seasons. As much as 19 native fish species with varied relative abundances and dominances were identified. Jute retting impacted lower native fish diversity indices like Shannon-Wiener index values (1.94 to 2.68) clearly indicated poor to moderate pollution status of the transitory water body in that area during monsoon in particular and throughout the year in general. So we opined there should be some control over the intense jute retting in the road side transitory water bodies for sustainable management of these manmade resources.

Fish diversity in different habitats in the streams of lower middle Western Himalayas

Johal M., Krishan-Tandon Kewal, Kumar-Tyor Anil, Kumar-Rawal Yogesh

Polish Journal of Ecology

2002

Vol. 50, nr 1

45-56

The present study was carried out in the lower middle Western Himalayan streams in the Indian state of Himachal Pradesh of the three river basins namely the Ghaggar, the Sutlej and the Yamuna. The main aim was to study fish assemblage structure/composition, fish diversity in different habitats and the habitat preference of the fishes. The different habitats like pools, riffles, runs and rapids were sampled over a 2 km stretch at all the sites with the help of cast net of 1 cm mesh size having a diameter of 1-2 meter on a fixed day every month between mid morning and late afternoon. All the sites when broadly delineated at level-1 fall into type - B except site II that is an F - type stream. A total of 23 species belonging to four orders were recorded of which the cyprinids were the most dominant group. According to Shannon-Weawer diversity index, the pool habitat supports greater diversity (H' = 0.72-0.97), Runs (H' = 0.24-0.87) and riffles (H' = 0.22-0.81) have diversity very near to each other at all the sites whereas rapids have significantly lower fish diversity (H' = 0.00-0.58). The pool is the preferred habitat for most of the cyprinid fishes recorded in the present study especially the minnows.