also differed from the control area. Species niamber and composition, 

 number of individuals, species diversity, evenness, and trophic dominance 

 all changed. 



The sequence of recolonization after dredging occurred in two parts: 

 First, two opportunistic species (worms Cccpitella sp. and Armondis sp.) 

 quickly occupied the newly exposed bottom. They are poor competitors, 

 and have a short reproductive cycle and high dispersal capabilities. 

 Second, the community dominant, Phoronopsis , became established and was 

 still dominant after 1.5 years. 



Temporal variations in bottom communities, the sequence and rate of 

 colonization, and the end state of recolonization can be predicted only 

 if the reproductive patterns of the local benthic fauna are known; e.g., 

 larvae settling jars and benthic samples. Data from the different sources 

 show that many of the benthic organisms spawn in the spring and fall sea- 

 sons although some animals reproduce throughout the year. 



Organisms adapted to unstable bottom conditions survive burial better 

 than others do; however, disposal caused about 60-percent reduction in the 

 number of individuals in the area. The number of different species drop- 

 ped slightly. During recovery the number of species increased for the 

 first year then decreased. Species composition was more stable than rela- 

 tive abundance. Many worm species were present throughout the study period 

 but mollusks and crustaceans occurred irregularly. The number of individ- 

 uals was still 60 percent lower 1.5 years after disposal, but the species 

 diversity and evenness were higher. 



The results of this study suggest: 



1. The ultimate recovery or recolonization of a dredged area or a 

 disposal area depends upon the timing of the action in relation to the 

 reproduction cycles and distributive abilities of the benthic organisms 

 present in and around the area. 



2. In Monterey Bay, spring and fall are the most active spawning 

 seasons for many benthic organisms; dredging or dumping should be avoided 

 at those times. 



3. Underwater disposal of dredged material should be made in unstable 

 areas if possible. 



4. Dredged areas or disposal areas may take more than 1.5 years to 

 return to the original conditions. 



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