10 to 30 cm in diameter with polyp-like protuberances evenly 

 spaced around its surface. There appeared to be no difference in 

 the assemblages living on the CaC0~ slabs versus the chimneys. 



The invertebrates associated with hard substrate are 

 suspension feeders and carnivores. The psolid sea cucumber 

 Psolus chitonoides uses branched, dendritic tentacles to capture 

 detrital particles from the water; these oral tentacles are 

 arrayed dorsally above the animal. The comatulid crinoid 

 Florometra serratissima suspension-feeds with highly pinnulated 

 arms projected into the overlying water layer ( Hyman 1955; Barnes 

 1980). There are also abundant unidentified small actiniarians 

 on the hard substrate surfaces. Photographs document that a 

 shrimp species utilizes rock overhangs for protection; they are, 

 therefore, associated with the rocky environment. Occasionally, 

 carnivorous asteroids (e.g. Luidia foliolata , Solaster sp. , 

 Pisaster sp. ) clung to the rock surface, presumably feeding 

 (Carey 1972). 



Several soft bottom invertebrates occurred in dense patches. 

 All box crabs seen ( Lopholithodes foraminatus ) occurred in large, 

 extremely dense patches (up to 25 individuals per m ); one patch 

 was at Station A on a broad stretch of sandy mud (Fig. 1). We 

 observed the other aggregation at Station C on mud in both 

 shallow depressions and on small ridge tops. The crabs were 

 facing in one direction and moving their mouthparts rapidly, 

 probably feeding. Though ophiuroids occurred over much of the 

 study area, an extensive, dense patch (up to 285 individuals per 

 m^ ) of at least two species was observed at Station B. Less 

 dense echinoid patches occurred on featureless stretches of 

 sediment (7 individuals per m ). 



Clear differences exist between fish species assemblages in 

 the different habitats. Many more species were identified from 

 all mud and mud near rock than from rock near mud and all rock 

 substrates (Table 2). Flatfishes, zoarcids, agonids, cottids, 

 skates, and thornyheads did not occur on rock. Both species 

 identified from all rock substrates ( sharpchin and rosethorn 

 rockfish) occurred over all mud. The greatest concentrations of 

 fish occurred on jumbled carbonate mounds, although a few 

 individual rockfish used small donut-shaped vent chimneys for 

 shelter. 



All rocky habitat fishes seen were Sebastes spp. Other 

 species probably occur also. The most common rockfish was the 

 sharpchin, S_;_ zacentrus . It occurred whenever rock was present, 

 often in substantial numbers. Unlike Heceta Bank rocky areas 

 ( Pearcy et al . in press), no small juvenile rockfishes were 

 present. Although it is not evident from the still photographs, 

 visual observational notes and video tapes suggest that neither 

 of the two rocky habitat species identified stray far from rock. 



144 



