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International Journal of Marine Science 2014, Vol.4, No.66, 1-11
http://ijms.biopublisher.ca
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Figure 1 Study Area: Shore Platform, Dwarka (E→W lines denote direction of transect lines)
of field sampling. Field sampling of macroalgae was
planned in the months of April, June and October, 2013
considering sampling feasibility. These three months:
April, June and October represent three different
seasons: summer (March-May), monsoon (June-August)
and post-monsoon (October-December) respectively.
Field surveys/sampling were performed during the
low tides. For qualitative and quantitative assessment
GPS (Spheroid and Datum: WGS 84) tagged line
transect method was used. Maximum transect length
surveyed is 105.5 m and minimum is 24m. Length of
transect lines depended on the tidal exposure of the
shore platform during the field surveys. Maximum depth
of the subtidal zone sampled for macroalgae is 0.5m.
For quantitative assessment of the marine algae in the
given area, line transect was laid perpendicular to the
coast from land to sea with the help of a long rope (50
m) (Dhargalkar and Kavlekar, 2004). A sampling
point along the rope is marked depending on the
gradient and exposure of intertidal and subtidal areas.
In Saurashtra coast, the tidal amplitude is very high as
compared to other parts of the west coast and the
entire east coast of India. Growth of seaweeds in
intertidal and shallow subtidal regions can be easily
observed in this area as the spring tides expose the
intertidal area up to a maximum length of 1 km (Jha,
et al
.,
2009). Each of the three sections on the shore
platform was represented by one transect line: thus
resulting nine transect lines over three months’
sampling. Quadrates of 1 m
2
were positioned on the
transect lines wherever the algae growth, density and
diversity were high. Total thirty nine quadrates were
performed on the nine transect lines. GPS tagged
photos of quadrates were taken for further analysis.
Macroalgae species present within the quadrates were
sampled. All specimens were identified and the
specific numbers of individuals were registered for
quantitative assessment of frequency.
3.3 Field data analysis
Collected macroalgae samples were taken to laboratory
for preparation of herbarium sheets and specimen
identification. Morphological criteria and reproductive
structure were analyzed for taxa identification.
Cladograms were prepared for identifying species in order
to generate classification statistics (number of genera
and species pertaining to different classes) (Figure 2).