6.0 SUBTIDAL BENTHOS 



by David J. Hartzband and Andrew J. McCusker 

 Normandeau Associates, Inc., Bedford, N. H. 



Richard McGrath and Allan B. Michael 

 Taxon, Inc., Salem, Mass. 



Donald A. Rhoads 

 Department of Geology and Geophysics, Yale University, New Haven, Conn, 



INTRODUCTION 



study of the population dynamics of benthic species can pro- 

 vide important insights into long-term disturbance history of the sea- 

 floor. Benthic species, especially infauna, are relatively immobile as 

 adults and therefore are exposed to changes in the ambient environment. 

 Changes in environmental quality are reflected both in selective mor- 

 tality of adults and also in the recruitment success of newly settled 

 larvae. 



The temporal and spatial persistence of the species composi- 

 tion at a particular location reflects the temporal and spatial sta- 

 bility of the habitat. In polluted, or otherwise dynamically changing 

 environments, the benthos are in a continual state of successional 

 change. The species composition of such a low-order successional stage 

 is very unpredictable. In less variable physical and chemical habitats, 

 the benthic fauna can maintain its structure for longer periods of time. 

 Biotic interactions can develop and the organisms can modify their 

 environment to some degree. This internal "stasis" is manifested in 

 persistent and predictable species associations. 



Long-term observations are necessary to document the dynamics 

 of benthic populations. Without the time perspective, it is presently 

 not possible to distinguish a pioneer benthic stage from a persistent 

 climax comm\inity. 



The purpose of this study was to detect any acute or long-term 

 changes in the New Haven Harbor benthos which might be attributable to 



6-1 



