Impact of Bottom Trawling on Sediment Texture and Organic Matter Along Inshore Waters of Kerala (South India)
Impact of Bottom Trawling on Sediment Texture and Organic Matter Along Inshore Waters of Kerala (South India)
Date
2005
Authors
Thomas, Joice V.
Kurup, B. Madhusoodana
Journal Title
Journal ISSN
Volume Title
Publisher
Society of Fisheries Technologists (India)Cochin
Abstract
Sediment texture and organic matter were analysed before and after trawling in samples
collected from 0-50 m depth zone during December 2000-November 2001, along Kerala coast
(Long. 75° 56/00 to 76o10' and Lat. 9058' to 10010'). Up to 40 m depth the composition of
sand, silt and clay were 0.19 - 15.8%, 35.33 -60.53% and 29.9 - 53.12% respectively. Beyond
' this, sand was dominant (sand 32.6 - 96.15, silt 1.8 - 33.8, clay 2.45- 26.48%). In samples
collected before trawling, sand, silt and clay ranged from 4.76 - 87, 45.85-55.71 and 43.18
- 47.38% respectively. In the samples collected after trawling the corresponding values for
sand, silt and clay were 21.25 - 35.7, 51.28 -63.92 and 13.03 - 21.6% respectively. Organic
carbon in 0-30 m depth zone ranged from 0.229 - 7.68% and it showed highest variations
in July especially at depths 0-10 m and 10-20 m with respective values of 4.45 and 4.75%
before trawling; while in the after trawling samples it was reduced to 2.21 % and 1.90%
respectively. The sand and silt fractions showed a significant increase whereas a drastic
reduction in clay fraction was observed especially in 0- 40 m depth zone due to bottom
trawling
Description
Keywords
Effect of trawling, organic matter, sediment texture
Citation
Fishery Tech 42(2):135-140