FISHERY BULLETIN: VOL. 78, NO. 2 



brates along a subtidal high-energy beach; and to 

 examine the relationship between community zo- 

 nation and wave-induced bottom disturbance. 

 Understanding the role of this predominant 

 physical process is critical to subsequent studies of 

 biological phenomena and their interactions with 

 the physical sedimentary environment. 



METHODS 



The study area was in central Monterey Bay, 

 Calif, on the sandflats adjacent to the Monterey 

 Submarine Canyon and along a ridge in the can- 

 yon head (Figure 1). The southern sandflat 

 transect was the main study site (Figures 1, 2). 

 Stations in 6 (M-1), 9 (M-2), 14 (M-3), 18 (M-4), and 

 24 m (M-5) of water were sampled at approxi- 

 mately the same time from June 1971 to June 

 1974. Three stations (9, 18, 24 m) were sampled 



N3 ^• 



DEPTH CONTOURS IN METERS 



I2I°48' 



Figure l.— Southern ( M) and northern (N) sandflat stations and 

 the canyon transect (A-D) in central Monterey Bay, Calif. N-5 

 and N-6 were directly east of N-4, 0.5 and 1 km, respectively. 



along the northern sandflat from August 1974 to 

 June 1975 (Figure 1; N stations). The maximum 

 interval between sampling periods was 3 mo. 

 Therefore, samples were taken during at least the 

 four major seasons at each station. The two deep- 

 est stations along the northern sandflat (N-5, 30 

 m; N-6, 40 m) were only sampled in May 1975. 

 Samples were treated separately to document sea- 

 sonal patterns and were combined over the study 

 period for each station to examine general zonal 

 patterns. 



A third, but much shorter transect (40 m long) 

 was located along a flat ridge in the head of the 

 Monterey Submarine Canyon ( Figure 1 ) . Four sta- 

 tions were established at 10 m intervals and at a 

 constant water depth of 14 m. One end of the 

 transect (station D) was highly disturbed by the 

 slumping of sediment down an adjacent terrace 

 wall. No sediment slumping occurred along the 

 opposite end of the transect (station A) (see En- 

 vironmental Setting section). The movement of 

 sediment by slumping was measured by periodic 

 depth soundings along the terrace wall and by 

 diver observations and measurements at perma- 

 nent underwater stations. Divers measured the 

 distance from the bottom to the tops of the steel 

 station rods at monthly intervals from May to 

 November 1972. Periodic visual observations of 

 station migrations and algal accumulations pro- 

 ceeded until mid-1974. 



All samples and field observations were made by 

 divers using scuba. Routine samples were taken 

 with diver-held can corers (length = 17 cm; area = 

 0.018 m^) and were washed over a 0.5 mm screen 

 in the laboratory. Eight replicate can cores were 

 usually taken in a haphazard fashion (Fager 1968) 

 at each station on each sampling date. The can 

 corers were 3-lb coffee cans with both ends re- 

 moved. Animal and sediment loss were prevented 

 by water-tight snap-on plastic lids. Residues were 

 fixed in 4% formaldehyde and transferred to 70% 

 ethanol after sorting. The macrofaunal inverte- 

 brates were identified to species (i.e., nematodes, 

 foraminiferans, and copepods were excluded). 



A long, diver-operated corer (length = 60 cm; 

 area = 0.018 m^) was used to document the verti- 

 cal distribution of organisms within the sediment 

 at southern sandflat stations in 9, 18, and 30 m of 

 water during August 1972. To maintain the strata 

 and minimize animal movement through them, 

 the corers were held horizontally after sample pro- 

 curement. Some cores were sectioned immediately 

 in the boat and others were sectioned within an 



438 



