Table 3.5.4. Fifty most abundant benthic taxa in the West Coast shelf survey 
region wide. Average density per m 2 , and percent frequency of occurrence 
based on 256 grabs. Classification: Native = native species; Crypto = 
cryptogenic species (of uncertain origin); Indeter = indeterminate taxa (not 
identified to a level that would allow determination of origin). 
Taxa Name 
Taxon 
Classification 
Average 
#/m 2 
% 
Frequency 
Mediomastus spp. 
Polychaete 
Indeter 
141.9 
62.9 
Axinopsida serricata 
Bivalve 
Native 
124.8 
67.2 
Magelona longicornis 
Polychaete 
Native 
105.3 
23.0 
Amphiodia urtica 
Ophiuroid 
Native 
87.5 
43.4 
Spiophanes berkeleyorum 
Polychaete 
Native 
86.8 
77.0 
Pinnixa occidentalis 
Decapoda 
Native 
82.0 
27.3 
Spiophanes bombyx 
Polychaete 
Native 
81.2 
41.8 
Euphilomedes 
Ostracod 
Native 
73.6 
46.1 
carcharodonta 
Spiophanes duplex 
Polychaete 
Native 
73.2 
44.9 
Prionospio jubata 
Polychaete 
Native 
67.2 
71.9 
Chloeia pinnata 
Polychaete 
Native 
55.0 
40.2 
Owenia fusiformis 
Polychaete 
Crypto 
48.2 
10.9 
Myriochele striolata 
Polychaete 
Native 
47.7 
10.5 
Galathowenia oculata 
Polychaete 
Crypto 
45.1 
33.2 
Ampelisca agassizi 
Amphipod 
Native 
43.4 
30.5 
Decamastus gracilis 
Polychaete 
Native 
42.0 
46.1 
Paraprionospio pinnata 
Polychaete 
Native 
39.3 
70.7 
Scoletoma luti 
Polychaete 
Native 
38.6 
31.3 
Euclymeninae sp. A 
Polychaete 
Native 
37.2 
58.6 
Amphiodia spp. 
Ophiuroid 
Indeter 
34.7 
48.0 
Sternaspis fossor 
Polychaete 
Crypto 
34.7 
46.9 
Rochefortia tumida 
Bivalve 
Native 
33.4 
41.0 
Euclymeninae 
Polychaete 
Indeter 
29.7 
49.6 
Lumbrineris cruzensis 
Polychaete 
Native 
28.6 
45.7 
Levinsenia gracilis 
Polychaete 
Crypto 
28.5 
38.3 
Ampelisca careyi 
Amphipod 
Native 
28.0 
62.5 
Pholoe glabra 
Polychaete 
Native 
26.7 
44.9 
Phoronida 
Phoronid 
Indeter 
26.7 
28.1 
Aphelochaeta glandaria 
Polychaete 
Native 
25.8 
33.2 
Paradiopatra parva 
Polychaete 
Native 
25.6 
37.1 
Prionospio lighti 
Polychaete 
Native 
25.5 
34.4 
Monticellina cryptica 
Polychaete 
Native 
23.8 
29.3 
Edwardsiidae 
Actiniarian 
Indeter 
23.6 
10.9 
Aricidea catherinae 
Polychaete 
Crypto 
23.4 
36.3 
Pseudofabriciola 
Polychaete 
Native 
23.2 
2.3 
californica _ 
Photis spp. 
Amphipod 
Indeter 
21.1 
32.8 
85 
