Rocky Intertidal Studies 



Introduction 



Rocky shores, and the communities which de- 

 velop upon them, are important components of 

 the marine ecosystem. The intertidal community 

 is among the most productive of the world (Mann 

 1973). The plants and animals provide food di- 

 rectly and indirectly to fish, birds, invertebrates, 

 even man (Edwards et al. 1982; Mcnge 1982); 

 they are involved in complex patterns of energy 

 and nutrient transfer (Paine 1966, 1980). 



Rocky intertidal communities are particularly 

 suitable for environmental impact assessments. 

 The shores are biologically productive but phys- 

 ically stable; the same area, in many cases the 

 same individual plants and animals, may be sam- 

 pled over time. Perennial algae and sessile 

 invertebrates integrate the effects of long-term ex- 

 posure to potential impacts, while motile species 

 and ephemeral algae respond to quickly changing 

 conditions. These characteristics have led to the 

 use of intertidal communities throughout the 

 world for assessment of impacts associated with, 

 e.g., oil spills (Southward and Southward 1978), 

 sewage (Murray and Littler 1978), and thermal 

 pollution (Vadas et al. 1976). Specifically, eco- 

 logical monitoring programs at every ocean-sited 

 nuclear power plant in New England have in- 

 cluded rocky shore studies (MYAPCO 1978; 

 Wilce et al. 1978; NAI 1984). 



Rocky shores in the vicinity of MNPS have 

 been subjected to potential impacts resulting from 

 construction and operation of the power station 

 since 1965. To assess these impacts, the Rocky 

 Intertidal Studies were designed and implemented 

 with the following objectives: 



to identify the attached plant and animal spe- 

 cies found on nearby rocky shores. 



2. to identify and quantify temporal and spatial 

 patterns of occurrence and abundance of 

 these species, and 



3. to identify the physical and biological factors 

 that induce variability in local rocky intertidal 

 communities. 



To achieve these objectives, the rocky intertidal 

 studies include qualitative algal collections, abun- 

 dance measurements of intertidal organisms (per- 

 centage of substratum coverage), measurement of 

 rates and patterns of recolonization following 

 small-scale perturbation, and growth studies of 

 Ascophyllum nodosum. This report will discuss 

 results of studies performed during the Unit 3 

 operational period to date (March 1986-Septem- 

 ber 1987), and compare them to data collected 

 from March 1979 to February 1986 (i.e., the pre- 

 operational period, "pre-op") and summarized in 

 NUSCO (1987). We will assess whether differ- 

 ences exist among communities near MNPS and 

 those removed from potential impact, and whether 

 the magnitude of those differences has changed 

 since 3-unit operations began. 



Materials and Methods 



Qualitative Collections 



The benthic algal flora at nine rocky intertidal 

 stations (Eig. 1) was monitored qualitatively on 

 a monthly basis. These stations are, in order of 

 most to least exposed: Bay Point (BP), Fox 

 Island-Exposed (EE), Millstone Point (MP), 

 Twotree Island (TT), White Point (WP), Seaside 

 Exposed (SE), Seaside Sheltered (SS), Giants 

 Neck (GN), and Fox Island-Sheltered (FS). 



Qualitative collections were made over an area 

 sufficiently wide to characterize the flora at each 

 site. Samples were identified fresh or after short- 



Rocky Intertidal Studies 



