L - Cochin University of Science and Technology

Nephtydae (2%). Among the 20 sedentarians families Cirratulidae contributed
maximum (19.7%) to the total density followed by Spionidae (15.2%), Capitellidae
(7.2%), Ampharetidae (8.3%), Cossuridae (5%) and Terebellidae (3.6%). Of the total
133 polychaete species encountered, errantia was represented by 43 species and
sedentaria by 90 species.
Depth wise occurrence of different polychaetes species is presented in Table
20. At 30 m depth zone, 52 species were present of which 12 species were of errant
type and 40 were sedentarian. Of the 52 species, 6 species were considered as
'abundant' (Ancystrosillis constricta, Lumbrineries hartmani, Prionospio pinnata, P.
po(vbranchiata, Cossura coasta and Capitella capitata) and 21 species were
'moderately abundant' among which Nephtys dibranchis, Prionospio cirrobranchia,
P. cirrifera, Magelona cincta, Ciriformia ajer, Heteromastus bifidis, Notomastus
fauvelli, Schyphoproctus sp. and Sternaspis scutata were the major ones (present>
50% of the stations). The remaining 25 species can be considered as 'rare'. In this
zone, species which contributed more to the total density were Cossura coasta
(730/m2), Prionospio pinnata (600/m2), P. polybranchiata (530/m2), and Sternaspis
scutata (490/m2)
At 50 m zone, 58 species were obtained of which 18 species were errant forms
and 40 were sedentarians. Of the 58 species, 8 were 'abundant' (Ancistrosyllis
constricta, Nephtys dibranchis, Lumbrineries aberrans, Prinospio pinnata, P.
polybranchiata" Cossura coasta, Capitella capitata and Sternaspis scutata) and 50
were 'moderately abundant' of which Glycera longipinnis, Lumbrineries hartmani.
Prinospio cirrobranchiataa, P. cirrifera, Magelona cincta, Cirratulis cirratus,
Cirriformia afer, Paraonides lyra lyra , Aricidea fauveli, Notomastus abberans,
Paraheteromastus tenuis, Amphictius gunneri, and Etione sp. were the major ones
and no species could be considered as 'rare'. In this depth zone Ancistrosyllis
135