L - Cochin University of Science and Technology

the organic rich environment with high OM. The present study also confinns the
above fact. Joydas (2002) observed the dominance of spionids and cirratulids in the
low oxygen environments. Ingole et al., (2002) noticed the dominance of spionids in
the coastal waters of Dabhol, west coast of India. Among spionids, Prinospio pinnata
was the most abundant species. The abundance of spionids in the deeper depths
showed that these organisms have a low metabolic rate and can withstand adverse
conditions. The decrease in temperature with increase in depth supports the above
statement.
7.5. Multiple regression analysis
Step up predictive multiple regression model for biomass and density of
polychaetes, crustaceans, molluscs, miscellaneous groups and total benthos from the
environmental factors during post-monsoon and pre-monsoon season was carried
out.
A total of 8 parameters were measured among which a set of highly
correlated 6 factors were selected during post-m on soon and pre-monsoon season as
the input variables along with their first order interaction effects. This model selects
the one, which could explain the maximum variability from a set of 64 models for
each of the three transfonnations viz,
1. original values of densitylbiomass on original values of the input
factors
2. original values of density/biomass on log 10 of input factors
3. log 10 of density/biomass on log 10 of input factors
In each case, the factors were standardized to standard nonnal variables as
y-y x-x
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