L - Cochin University of Science and Technology

cm 2 with a dominance of nematodes. In general no distinct transect wise trend was
observed.
Percentage contribution within individual group at different depth (Table 13)
showed that contribution of nematodes decreased with increasing depth while, rest of
the groups showed an opposite trend. Highest contribution of nematodes was at 30 m
(56.7%) and lowest at 150 m (1.5 %). Copepods contributed maximum at 150 m
zone (37.4%) and minimum at 50 m zone (9%). Miscellaneous groups also have
relatively lower percentage contribution at 30 m (19.7%) and higher contribution at
deeper depths of 100 m (28.5%), but exceptionally low value at 150 m (3.6%).
5.2.4.2. Pre-monsoon
Density followed the similar trend as that of biomass with relatively low
density at the 30 m depth off Mormugao and Mumbai while, high density was
observed at 30 m depth off Ratnagiri, Veraval and Dwaraka (Table 14). Overall
percentage contribution by various groups to the total density (Table 14) showed that
nematodes contributed more to the total density (65.3%) followed by foraminifers
(25%) and miscellaneous groups (8%). Copepods were the least abundant group
(1.3%).
5.2.5. Seasonal comparison
In general, average biomass and density of macrobenthos in the whole study
area were high during pre-monsoon season than post-monsoon period (Fig. 33&34).
In both seasons shallow depth stations registered high biomass and density, while it
reduced considerably in deeper stations with some exceptions. During post-monsoon,
even though no regular trend was observed, average biomass showed comparatively
high value in the northern transect than its southern counterpart (Fig. 26). Biomass
showed a northward increase during pre-monsoon. Average value of this season also
showed comparatively high value in the northern transect than southern transect
(Fig. 27), however, exceptionally high biomass was observed at 75 m depth otT
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