abundance in the intertidal zone and eighth at the 3.7-meter stations 

 (Table 11). Maximum abundance was at the 3.7-meter depth where esti- 

 mated densities exceeded 1,200 per square meter [Table 14). Inter- 

 tidally, abundances reached 293 per square meter (Table 10) for survey 

 IV (postdisposal) and this was the only time they were not found at the 

 offshore stations. This correlates with a period of low wave energies 

 and possibly indicates an onshore movement of this species during 

 periods of calm weather (Fig. 7). There was no significant detectable 

 response of cumacean species to beach replenishment. 



(7) Decapods (Crabs) . Many of the nearshore decapods are 

 significant components of the nearshore biomass. Their densities were 

 generally low and they tended to be highly aggregated. 



(a) Ble-phar-ipoda oooidentalis (Spiny Sand Crab) . Adults 

 of this large crab were only found intertidally and their biomass ac- 

 counted for 45 to 78 percent of the station biomass (Table 16) . Less 

 than two per square meter were generally found. Juveniles were off- 

 shore and their densities were higher. This possibly indicates an 

 onshore migration with maturity. 



(b) Emerita anatoga (Sand Crab) . This sand crab ranked 

 fourth in abundance (Table 11) and was taken consistently in the inter- 

 tidal zone but never collected offshore. Estimated densities varied 

 from 2 to 142 per square meter with the highest densities occurring at 

 intertidal stations A and B for survey IV (postdredge disposal) . This 

 may have been due to seasonal recruitment at this time, but high numbers 

 were not observed at station C. However, at this time the upper inter- 

 tidal of station C had eroded to cobble and this probably lowered the 

 biological attractiveness of this station for Emerita (see Fig. 4). 



In survey V, abundances of Emerita were not significantly different 

 between stations. Beach replenishment may have had some positive effect 

 on Emerita densities, but at best this was a short-lived phenomena. 

 There appears to be no long-lasting adverse effects of beach replenish- 

 ment on this species. This species is noted for its longshore movement, 

 and patchy distribution and recruitment patterns (Barnes and Wenner, 

 1968). 



c. Polychaetes . The significant role that polychaetes play in 

 the dynamics of soft-bottom communities was reviewed by Knox (1977). 

 Five species of polychaetes that were numerically abundant are discussed 

 in relation to their response to beach replenishment. 



(1) Apopvionospio pygmaea . This polychaete worm ranked 

 second in abundance at the 3.7- and 6.1-meter stations and reached 

 densities estimated at 4,700 per square meter (Fig. 37, Table 11). On 

 the east coast, this species was a numerical dominant in the repopu- 

 lation of a protected intertidal area following defaunation of the 

 sediments (Dauer and Simon, 1976). However, in California the response 

 of this opportunistic species to disturbance gradients shows no consis- 

 tent trend (Oliver, 1977). Densities fluctuated over hundredfold 



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