EFFECTS OF DREDGING AND DISPOSAL ON SOME BENTHOS 

 AT MONTEREY BAY, CALIFORNIA 



hy 

 John S. Oliver and Peter N. Slattery 



I. INTRODUCTION 



There have been a number of large-scale surveys of the effects of 

 dredging and dredged material disposal on benthic communities. Most per- 

 tinent to this study were parts of multidisciplinary field studies on the 

 gross physical and biological effects of disposal of dredged material in 

 the Chesapeake Bay (Virginia Institute of Marine Science, 1967; 

 Pfitzenmeyer, 1970) and the Rhode Island Sound (Sailia, Pratt, and Polgar, 

 1972]. Additional reviews were presented by Sherk (1971), O'Neal and 

 Sceva (1971), and Thompson (1973). Sherk and Cronin (1970) published an 

 annotated bibliography of selected references on the same subject. 



Because of the shortcomings of some surveys, the practical problems 

 encountered, and the limitations of the local situation, a number of spec- 

 ific objectives and designed sampling procedures were established to 

 produce detailed answers. A minimum of laboratory work was planned so 

 that maximum effort could be devoted to field sampling and experimenta- 

 tion. The development of a quantitative sampling plan (App. A) and 

 exploration of sampling techniques preceded the study. 



The objectives of the study were to: 



(a) Document changes in benthic assemblages related to 

 sediment movement or substrate stability; 



(b) document natural temporal variations within a benthic 

 assemblage and investigate the biological and physical proc- 

 esses that might explain these variations; 



(c) document the initial effects of dredged material 

 disposal and subsequent recovery of the benthic fauna; 



(d) document the sequence of recolonization of a benthic 

 assemblage within a dredged bottom area; 



(e) study the mechanisms controlling benthic recovery and 

 recolonization, especially faunal distributions and reproduc- 

 tive abilities; 



(f) compare the effect of mass accumulation of sediment 



on benthic assemblages adapted to different levels of substrate 

 stability; and 



(g) provide additional information relevant to the planning 

 of local dredging operations. 



